SUIT                                                            B. Moran
Internet-Draft                                             H. Tschofenig
Intended status: Standards Track                             Arm Limited
Expires: 29 April 2022                                       H. Birkholz
                                                          Fraunhofer SIT
                                                             K. Zandberg
                                                                   Inria
                                                         26 October 2021

A Concise Binary Object Representation (CBOR)-based Serialization Format
    for the Software Updates for Internet of Things (SUIT) Manifest
                      draft-ietf-suit-manifest-15
                      draft-ietf-suit-manifest-16

Abstract

   This specification describes the format of a manifest.  A manifest is
   a bundle of metadata about code/data obtained by a recipient (chiefly
   the firmware for an IoT device), where to find the that code/data,
   the devices to which it applies, and cryptographic information
   protecting the manifest.  Software updates and Trusted Invocation
   both tend to use sequences of common operations, so the manifest
   encodes those sequences of operations, rather than declaring the
   metadata.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on 29 April 2022.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Conventions and Terminology . . . . . . . . . . . . . . . . .   6
   3.  How to use this Document  . . . . . . . . . . . . . . . . . .   8
   4.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     4.1.  IoT Firmware Update Constraints . . . . . . . . . . . . .   9
     4.2.  SUIT Workflow Model . . . . . . . . . . . . . . . . . . .  10
   5.  Metadata Structure Overview . . . . . . . . . . . . . . . . .  11
     5.1.  Envelope  . . . . . . . . . . . . . . . . . . . . . . . .  12
     5.2.  Authentication Block  . . . . . . . . . . . . . . . . . .  12
     5.3.  Manifest  . . . . . . . . . . . . . . . . . . . . . . . .  13
       5.3.1.  Critical Metadata . . . . . . . . . . . . . . . . . .  13
       5.3.2.  Common  . . . . . . . . . . . . . . . . . . . . . . .  13
       5.3.3.  Command Sequences . . . . . . . . . . . . . . . . . .  14
       5.3.4.  Integrity Check Values  . . . . . . . . . . . . . . .  14
       5.3.5.  Human-Readable Text . . . . . . . . . . . . . . . . .  14
     5.4.   Severable Elements . . . . . . . . . . . . . . . . . . .  15
     5.5.  Integrated Payloads . . . . . . . . . . . . . . . . . . .  15
   6.  Manifest Processor Behavior . . . . . . . . . . . . . . . . .  15
     6.1.  Manifest Processor Setup  . . . . . . . . . . . . . . . .  16
     6.2.   Required Checks  . . . . . . . . . . . . . . . . . . . .  17
       6.2.1.  Minimizing Signature Verifications  . . . . . . . . .  18
     6.3.  Interpreter Fundamental Properties  . . . . . . . . . . .  18
     6.4.  Abstract Machine Description  . . . . . . . . . . . . . .  19
     6.5.  Special Cases of Component Index  . . . . . . . . . . . .  21
     6.6.  Serialized Processing Interpreter . . . . . . . . . . . .  22
     6.7.  Parallel Processing Interpreter . . . . . . . . . . . . .  22
   7.  Creating Manifests  . . . . . . . . . . . . . . . . . . . . .  23
     7.1.  Compatibility Check Template  . . . . . . . . . . . . . .  23
     7.2.  Trusted Invocation Template . . . . . . . . . . . . . . .  24
     7.3.  Component Download Template . . . . . . . . . . . . . . .  24
     7.4.  Install Template  . . . . . . . . . . . . . . . . . . . .  25
     7.5.  Integrated Payload Template . . . . . . . . . . . . . . .  25
     7.6.  Load from Nonvolatile Storage Template  . . . . . . . . .  26
     7.7.  A/B Image Template  . . . . . . . . . . . . . . . . . . .  26
   8.  Metadata Structure  . . . . . . . . . . . . . . . . . . . . .  28
     8.1.  Encoding Considerations . . . . . . . . . . . . . . . . .  28
     8.2.  Envelope  . . . . . . . . . . . . . . . . . . . . . . . .  28
     8.3.  Authenticated Manifests . . . . . . . . . . . . . . . . .  29
     8.4.  Manifest  . . . . . . . . . . . . . . . . . . . . . . . .  29
       8.4.1.  suit-manifest-version . . . . . . . . . . . . . . . .  30
       8.4.2.  suit-manifest-sequence-number . . . . . . . . . . . .  30
       8.4.3.  suit-reference-uri  . . . . . . . . . . . . . . . . .  30
       8.4.4.  suit-text . . . . . . . . . . . . . . . . . . . . . .  30
       8.4.5.  suit-common . . . . . . . . . . . . . . . . . . . . .  32
       8.4.6.  SUIT_Command_Sequence . . . . . . . . . . . . . . . .  33
       8.4.7.  Reporting Policy  . . . . . . . . . . . . . . . . . .  35
       8.4.8.  SUIT_Parameters . . . . . . . . . . . . . . . . . . .  36
       8.4.9.  SUIT_Condition  . . . . . . . . . . . . . . . . . . .  42
       8.4.10. SUIT_Directive  . . . . . . . . . . . . . . . . . . .  45
       8.4.11. Integrity Check Values  . . . . . . . . . . . . . . .  50
     8.5.  Severable Elements  . . . . . . . . . . . . . . . . . . .  50
   9.  Access Control Lists  . . . . . . . . . . . . . . . . . . . .  50
   10. SUIT Digest Container . . . . . . . . . . . . . . . . . . . .  51
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  51
     11.1.  SUIT Commands  . . . . . . . . . . . . . . . . . . . . .  52
     11.2.  SUIT Parameters  . . . . . . . . . . . . . . . . . . . .  53
     11.3.  SUIT Text Values . . . . . . . . . . . . . . . . . . . .  54
     11.4.   SUIT Component Text Values  . . . . . . . . . . . . . .  55
   12. Security Considerations . . . . . . . . . . . . . . . . . . .  55
   13. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  55
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . .  56
     14.1.  Normative References . . . . . . . . . . . . . . . . . .  56
     14.2.  Informative References . . . . . . . . . . . . . . . . .  57
   Appendix A.  A.  Full CDDL  . . . . . . . . . . . . . . . . . . .  58
   Appendix B.  B.  Examples . . . . . . . . . . . . . . . . . . . .  64
     B.1.  Example 0: Secure Boot  . . . . . . . . . . . . . . . . .  65
     B.2.  Example 1: Simultaneous Download and Installation of
           Payload . . . . . . . . . . . . . . . . . . . . . . . . .  67
     B.3.  Example 2: Simultaneous Download, Installation, Secure
           Boot, Severed Fields  . . . . . . . . . . . . . . . . . .  69
     B.4.  Example 3: A/B images . . . . . . . . . . . . . . . . . .  73
     B.5.  Example 4: Load from External Storage . . . . . . . . . .  76
     B.6.  Example 5: Two Images . . . . . . . . . . . . . . . . . .  79
   Appendix C.  C.  Design Rational  . . . . . . . . . . . . . . . .  82
     C.1.  C.1 Design Rationale: Envelope  . . . . . . . . . . . . .  83
     C.2.  C.2 Byte String Wrappers  . . . . . . . . . . . . . . . .  84
   Appendix D.  D.  Implementation Conformance Matrix  . . . . . . .  84
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  86

1.  Introduction

   A firmware update mechanism is an essential security feature for IoT
   devices to deal with vulnerabilities.  While the transport of
   firmware images to the devices themselves is important there are
   already various techniques available.  Equally important is the
   inclusion of metadata about the conveyed firmware image (in the form
   of a manifest) and the use of a security wrapper to provide end-to-
   end security protection to detect modifications and (optionally) to
   make reverse engineering more difficult.  End-to-end security allows
   the author, who builds the firmware image, to be sure that no other
   party (including potential adversaries) can install firmware updates
   on IoT devices without adequate privileges.  For confidentiality
   protected firmware images it is additionally required to encrypt the
   firmware image.  Starting security protection at the author is a risk
   mitigation technique so firmware images and manifests can be stored
   on untrusted repositories; it also reduces the scope of a compromise
   of any repository or intermediate system to be no worse than a denial
   of service.

   A manifest is a bundle of metadata describing one or more code or
   data payloads and how to:

   *  Obtain any dependencies

   *  Obtain the payload(s)

   *  Install them

   *  Verify them

   *  Load them into memory

   *  Invoke them

   This specification defines the SUIT manifest format and it is
   intended to meet several goals:

   *  Meet the requirements defined in
      [I-D.ietf-suit-information-model].

   *  Simple to parse on a constrained node

   *  Simple to process on a constrained node

   *  Compact encoding

   *  Comprehensible by an intermediate system
   *  Expressive enough to enable advanced use cases on advanced nodes

   *  Extensible

   The SUIT manifest can be used for a variety of purposes throughout
   its lifecycle, such as:

   *  a Firmware Author to reason about releasing a firmware.

   *  a Network Operator to reason about compatibility of a firmware.

   *  a Device Operator to reason about the impact of a firmware.

   *  the Device Operator to manage distribution of firmware to devices.

   *  a Plant Manager to reason about timing and acceptance of firmware
      updates.

   *  a device to reason about the authority & authenticity of a
      firmware prior to installation.

   *  a device to reason about the applicability of a firmware.

   *  a device to reason about the installation of a firmware.

   *  a device to reason about the authenticity & encoding of a firmware
      at boot.

   Each of these uses happens at a different stage of the manifest
   lifecycle, so each has different requirements.

   It is assumed that the reader is familiar with the high-level
   firmware update architecture [RFC9019] and the threats, requirements,
   and user stories in [I-D.ietf-suit-information-model].

   The design of this specification is based on an observation that the
   vast majority of operations that a device can perform during an
   update or Trusted Invocation are composed of a small group of
   operations:

   *  Copy some data from one place to another

   *  Transform some data

   *  Digest some data and compare to an expected value

   *  Compare some system parameters to an expected value
   *  Run some code

   In this document, these operations are called commands.  Commands are
   classed as either conditions or directives.  Conditions have no side-
   effects, while directives do have side-effects.  Conceptually, a
   sequence of commands is like a script but the language is tailored to
   software updates and Trusted Invocation.

   The available commands support simple steps, such as copying a
   firmware image from one place to another, checking that a firmware
   image is correct, verifying that the specified firmware is the
   correct firmware for the device, or unpacking a firmware.  By using
   these steps in different orders and changing the parameters they use,
   a broad range of use cases can be supported.  The SUIT manifest uses
   this observation to optimize metadata for consumption by constrained
   devices.

   While the SUIT manifest is informed by and optimized for firmware
   update and Trusted Invocation use cases, there is nothing in the SUIT
   Information Model ([I-D.ietf-suit-information-model]) that restricts
   its use to only those use cases.  Other use cases include the
   management of trusted applications (TAs) in a Trusted Execution
   Environment (TEE), as discussed in [I-D.ietf-teep-architecture].

2.  Conventions and Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   Additionally, the following terminology is used throughout this
   document:

   *  SUIT: Software Update for the Internet of Things, also the IETF
      working group for this standard.

   *  Payload: A piece of information to be delivered.  Typically
      Firmware for the purposes of SUIT.

   *  Resource: A piece of information that is used to construct a
      payload.

   *  Manifest: A manifest is a bundle of metadata about the firmware
      for an IoT device, where to find the firmware, and the devices to
      which it applies.

   *  Envelope: A container with the manifest, an authentication wrapper
      with cryptographic information protecting the manifest,
      authorization information, and severable elements (see: TBD).

   *  Update: One or more manifests that describe one or more payloads.

   *  Update Authority: The owner of a cryptographic key used to sign
      updates, trusted by Recipients.

   *  Recipient: The system, typically an IoT device, that receives and
      processes a manifest.

   *  Manifest Processor: A component of the Recipient that consumes
      Manifests and executes the commands in the Manifest.

   *  Component: An updatable logical block of the Firmware, Software,
      configuration, or data of the Recipient.

   *  Component Set: A group of interdependent Components that must be
      updated simultaneously.

   *  Command: A Condition or a Directive.

   *  Condition: A test for a property of the Recipient or its
      Components.

   *  Directive: An action for the Recipient to perform.

   *  Trusted Invocation: A process by which a system ensures that only
      trusted code is executed, for example secure boot or launching a
      Trusted Application.

   *  A/B images: Dividing a Recipient's storage into two or more
      bootable images, at different offsets, such that the active image
      can write to the inactive image(s).

   *  Record: The result of a Command and any metadata about it.

   *  Report: A list of Records.

   *  Procedure: The process of invoking one or more sequences of
      commands.

   *  Update Procedure: A procedure that updates a Recipient by fetching
      dependencies and images, and installing them.

   *  Invocation Procedure: A procedure in which a Recipient verifies
      dependencies and images, loading images, and invokes one or more
      image.

   *  Software: Instructions and data that allow a Recipient to perform
      a useful function.

   *  Firmware: Software that is typically changed infrequently, stored
      in nonvolatile memory, and small enough to apply to [RFC7228]
      Class 0-2 devices.

   *  Image: Information that a Recipient uses to perform its function,
      typically firmware/software, configuration, or resource data such
      as text or images.  Also, a Payload, once installed is an Image.

   *  Slot: One of several possible storage locations for a given
      Component, typically used in A/B image systems

   *  Abort: An event in which the Manifest Processor immediately halts
      execution of the current Procedure.  It creates a Record of an
      error condition.

3.  How to use this Document

   This specification covers five aspects of firmware update:

   *  Section 4 describes the device constraints, use cases, and design
      principles that informed the structure of the manifest.

   *  Section 5 gives a general overview of the metadata structure to
      inform the following sections

   *  Section 6 describes what actions a Manifest processor should take.

   *  Section 7 describes the process of creating a Manifest.

   *  Section 8 specifies the content of the Envelope and the Manifest.

   To implement an updatable device, see Section 6 and Section 8.  To
   implement a tool that generates updates, see Section 7 and Section 8.

   The IANA consideration section, see Section 11, provides instructions
   to IANA to create several registries.  This section also provides the
   CBOR labels for the structures defined in this document.

   The complete CDDL description is provided in Appendix A, examples are
   given in Appendix B and a design rational is offered in Appendix C.
   Finally, Appendix D gives a summarize of the mandatory-to-implement
   features of this specification.

   This specification covers the core features of SUIT.  Additional
   specifications will cover advanced use cases and update management
   needs:

   *  Firmware Encryption is covered in
      [I-D.ietf-suit-firmware-encryption]

   *  Update Management is covered in (TBD)

   *  Multiple Trust Domains (dependencies, key delegation, multiple
      processors, TEEs, etc.) are covered in (TBD)

   *  Update Compression is covered in (TBD)

4.  Background

   Distributing software updates to diverse devices with diverse trust
   anchors in a coordinated system presents unique challenges.  Devices
   have a broad set of constraints, requiring different metadata to make
   appropriate decisions.  There may be many actors in production IoT
   systems, each of whom has some authority.  Distributing firmware in
   such a multi-party environment presents additional challenges.  Each
   party requires a different subset of data.  Some data may not be
   accessible to all parties.  Multiple signatures may be required from
   parties with different authorities.  This topic is covered in more
   depth in [RFC9019].  The security aspects are described in
   [I-D.ietf-suit-information-model].

4.1.  IoT Firmware Update Constraints

   The various constraints of IoT devices and the range of use cases
   that need to be supported create a broad set of requirements.  For
   example, devices with:

   *  limited processing power and storage may require a simple
      representation of metadata.

   *  bandwidth constraints may require firmware compression or partial
      update support.

   *  bootloader complexity constraints may require simple selection
      between two bootable images.

   *  small internal storage may require external storage support.

   *  multiple microcontrollers may require coordinated update of all
      applications.

   *  large storage and complex functionality may require parallel
      update of many software components.

   *  extra information may need to be conveyed in the manifest in the
      earlier stages of the device lifecycle before those data items are
      stripped when the manifest is delivered to a constrained device.

   Supporting the requirements introduced by the constraints on IoT
   devices requires the flexibility to represent a diverse set of
   possible metadata, but also requires that the encoding is kept
   simple.

4.2.  SUIT Workflow Model

   There are several fundamental assumptions that inform the model of
   Update Procedure workflow:

   *  Compatibility must be checked before any other operation is
      performed.

   *  In some applications, payloads must be fetched and validated prior
      to installation.

   There are several fundamental assumptions that inform the model of
   the Invocation Procedure workflow:

   *  Compatibility must be checked before any other operation is
      performed.

   *  All payloads must be validated prior to loading.

   *  All loaded images must be validated prior to execution.

   Based on these assumptions, the manifest is structured to work with a
   pull parser, where each section of the manifest is used in sequence.
   The expected workflow for a Recipient installing an update can be
   broken down into five steps:

   1.  Verify the signature of the manifest.

   2.  Verify the applicability of the manifest.

   3.  Fetch payload(s).

   4.  Install payload(s).

   When installation is complete, similar information can be used for
   validating and running images in a further three steps:

   1.  Verify image(s).

   2.  Load image(s).

   3.  Run image(s).

   If verification and running is implemented in a bootloader, then the
   bootloader MUST also verify the signature of the manifest and the
   applicability of the manifest in order to implement secure boot
   workflows.  The bootloader may add its own authentication, e.g. a
   Message Authentication Code (MAC), to the manifest in order to
   prevent further verifications.

5.  Metadata Structure Overview

   This section provides a high level overview of the manifest
   structure.  The full description of the manifest structure is in
   Section 8.4

   The manifest is structured from several key components:

   1.  The Envelope (see Section 5.1) contains the Authentication Block,
       the Manifest, any Severable Elements, and any Integrated
       Payloads.

   2.  The Authentication Block (see Section 5.2) contains a list of
       signatures or MACs of the manifest..

   3.  The Manifest (see Section 5.3) contains all critical, non-
       severable metadata that the Recipient requires.  It is further
       broken down into:

       1.  Critical metadata, such as sequence number.

       2.  Common metadata, such as affected components.

       3.  Command sequences, directing the Recipient how to install and
           use the payload(s).

       4.  Integrity check values for severable elements.

   4.  Severable elements (see Section 5.4).

   5.  Integrated payloads (see Section 5.5).

   The diagram below illustrates the hierarchy of the Envelope.

   +-------------------------+
   | Envelope                |
   +-------------------------+
   | Authentication Block    |
   | Manifest           --------------> +------------------------------+
   | Severable Elements      |          | Manifest                     |
   | Human-Readable Text     |          +------------------------------+
   | COSWID Integrated Payloads     |          | Structure Version            |
   | Integrated Payloads     |
   +-------------------------+          | Sequence Number              |
   +-------------------------+
                                        | Reference to Full Manifest   |
                                  +------ Common Structure             |
                                  | +---- Command Sequences            |
   +-------------------------+    | |   | Digests of Envelope Elements |
   | Common Structure        | <--+ |   +------------------------------+
   +-------------------------+      |
   | Components IDs          |      +-> +-----------------------+
   | Common Command Sequence ---------> | Command Sequence      |
   +-------------------------+          +-----------------------+
                                        | List of ( pairs of (  |
                                        |   * command code      |
                                        |   * argument /        |
                                        |      reporting policy |
                                        | ))                    |
                                        +-----------------------+

5.1.  Envelope

   The SUIT Envelope is a container that encloses the Authentication
   Block, the Manifest, any Severable Elements, and any integrated
   payloads.  The Envelope is used instead of conventional cryptographic
   envelopes, such as COSE_Envelope because it allows modular
   processing, severing of elements, and integrated payloads in a way
   that would add substantial complexity with existing solutions.  See
   Appendix C.1 for a description of the reasoning for this.

   See Section 8.2 for more detail.

5.2.  Authentication Block

   The Authentication Block contains a bstr-wrapped SUIT Digest
   Container, see Section 10, and one or more [RFC8152] CBOR Object
   Signing and Encryption (COSE) authentication blocks.  These blocks
   are one of:

   *  COSE_Sign_Tagged

   *  COSE_Sign1_Tagged

   *  COSE_Mac_Tagged

   *  COSE_Mac0_Tagged

   Each of these objects is used in detached payload mode.  The payload
   is the bstr-wrapped SUIT_Digest.

   See Section 8.3 for more detail.

5.3.  Manifest

   The Manifest contains most metadata about one or more images.  The
   Manifest is divided into Critical Metadata, Common Metadata, Command
   Sequences, and Integrity Check Values.

   See Section 8.4 for more detail.

5.3.1.  Critical Metadata

   Some metadata needs to be accessed before the manifest is processed.
   This metadata can be used to determine which manifest is newest and
   whether the structure version is supported.  It also MAY provide a
   URI for obtaining a canonical copy of the manifest and Envelope.

   See Section 8.4.1, Section 8.4.2, and Section 8.4.3 for more detail.

5.3.2.  Common

   Some metadata is used repeatedly and in more than one command
   sequence.  In order to reduce the size of the manifest, this metadata
   is collected into the Common section.  Common is composed of two
   parts: a list of components referenced by the manifest, and a command
   sequence to execute prior to each other command sequence.  The common
   command sequence is typically used to set commonly used values and
   perform compatibility checks.  The common command sequence MUST NOT
   have any side-effects outside of setting parameter values.

   See Section 8.4.5 for more detail.

5.3.3.  Command Sequences

   Command sequences provide the instructions that a Recipient requires
   in order to install or use an image.  These sequences tell a device
   to set parameter values, test system parameters, copy data from one
   place to another, transform data, digest data, and run code.

   Command sequences are broken up into three groups: Common Command
   Sequence (see Section 5.3.2), update commands, and secure boot
   commands.

   Update Command Sequences are: Payload Fetch, and Payload
   Installation.  An Update Procedure is the complete set of each Update
   Command Sequence, each preceded by the Common Command Sequence.

   Invocation Command Sequences are: System Validation, Image Loading,
   and Image Invocation.  An Invocation Procedure is the complete set of
   each Invocation Command Sequence, each preceded by the Common Command
   Sequence.

   Command Sequences are grouped into these sets to ensure that there is
   common coordination between dependencies and dependents on when to
   execute each command (dependencies are not defined in this
   specification).

   See Section 8.4.6 for more detail.

5.3.4.  Integrity Check Values

   To enable Section 5.4, there needs to be a mechanism to verify
   integrity of any metadata outside the manifest.  Integrity Check
   Values are used to verify the integrity of metadata that is not
   contained in the manifest.  This MAY include Severable Command
   Sequences, or Text data.  Integrated Payloads are integrity-checked
   using Command Sequences, so they do not have Integrity Check Values
   present in the Manifest.

   See Section 8.4.11 for more detail.

5.3.5.  Human-Readable Text

   Text is typically a Severable Element (Section 5.4).  It contains all
   the text that describes the update.  Because text is explicitly for
   human consumption, it is all grouped together so that it can be
   Severed easily.  The text section has space both for describing the
   manifest as a whole and for describing each individual component.

   See Section 8.4.4 for more detail.

5.4.   Severable Elements

   Severable Elements are elements of the Envelope (Section 5.1) that
   have Integrity Check Values (Section 5.3.4) in the Manifest
   (Section 5.3).

   Because of this organisation, these elements can be discarded or
   "Severed" from the Envelope without changing the signature of the
   Manifest.  This allows savings based on the size of the Envelope in
   several scenarios, for example:

   *  A management system severs the Text sections before sending an
      Envelope to a constrained Recipient, which saves Recipient
      bandwidth.

   *  A Recipient severs the Installation section after installing the
      Update, which saves storage space.

   See Section 8.5 for more detail.

5.5.  Integrated Payloads

   In some cases, it is beneficial to include a payload in the Envelope
   of a manifest.  For example:

   *  When an update is delivered via a comparatively unconstrained
      medium, such as a removable mass storage device, it may be
      beneficial to bundle updates into single files.

   *  When a manifest transports a small payload, such as an encrypted
      key, that payload may be placed in the manifest's envelope.

   See Section 7.5 for more detail.

6.  Manifest Processor Behavior

   This section describes the behavior of the manifest processor and
   focuses primarily on interpreting commands in the manifest.  However,
   there are several other important behaviors of the manifest
   processor: encoding version detection, rollback protection, and
   authenticity verification are chief among these.

6.1.  Manifest Processor Setup

   Prior to executing any command sequence, the manifest processor or
   its host application MUST inspect the manifest version field and fail
   when it encounters an unsupported encoding version.  Next, the
   manifest processor or its host application MUST extract the manifest
   sequence number and perform a rollback check using this sequence
   number.  The exact logic of rollback protection may vary by
   application, but it has the following properties:

   *  Whenever the manifest processor can choose between several
      manifests, it MUST select the latest valid, authentic manifest.

   *  If the latest valid, authentic manifest fails, it MAY select the
      next latest valid, authentic manifest, according to application-
      specific policy.

   Here, valid means that a manifest has a supported encoding version
   and it has not been excluded for other reasons.  Reasons for
   excluding typically involve first executing the manifest and may
   include:

   *  Test failed (e.g.  Vendor ID/Class ID).

   *  Unsupported command encountered.

   *  Unsupported parameter encountered.

   *  Unsupported Component Identifier encountered.

   *  Payload not available.

   *  Application crashed when executed.

   *  Watchdog timeout occurred.

   *  Payload verification failed.

   *  Missing required component from a Component Set.

   *  Required parameter not supplied.

   These failure reasons MAY be combined with retry mechanisms prior to
   marking a manifest as invalid.

   Selecting an older manifest in the event of failure of the latest
   valid manifest is a robustness mechanism that is necessary for
   supporting the requirements in [RFC9019], section 3.5.  It may not be
   appropriate for all applications.  In particular Trusted Execution
   Environments MAY require a failure to invoke a new installation,
   rather than a rollback approach.  See
   [I-D.ietf-suit-information-model], Section 4.2.1 for more discussion
   on the security considerations that apply to rollback.

   Following these initial tests, the manifest processor clears all
   parameter storage.  This ensures that the manifest processor begins
   without any leaked data.

6.2.   Required Checks

   The RECOMMENDED process is to verify the signature of the manifest
   prior to parsing/executing any section of the manifest.  This guards
   the parser against arbitrary input by unauthenticated third parties,
   but it costs extra energy when a Recipient receives an incompatible
   manifest.

   When validating authenticity of manifests, the manifest processor MAY
   use an ACL (see Section 9) to determine the extent of the rights
   conferred by that authenticity.

   Once a valid, authentic manifest has been selected, the manifest
   processor MUST examine the component list and verify that its maximum
   number of components is not exceeded and that each listed component
   is supported.

   For each listed component, the manifest processor MUST provide
   storage for the supported parameters.  If the manifest processor does
   not have sufficient temporary storage to process the parameters for
   all components, it MAY process components serially for each command
   sequence.  See Section 6.6 for more details.

   The manifest processor SHOULD check that the common sequence contains
   at least Check Vendor Identifier command and at least one Check Class
   Identifier command.

   Because the common sequence contains Check Vendor Identifier and
   Check Class Identifier command(s), no custom commands are permitted
   in the common sequence.  This ensures that any custom commands are
   only executed by devices that understand them.

   If the manifest contains more than one component, each command
   sequence MUST begin with a Set Component Index.

   If a Recipient supports groups of interdependent components (a
   Component Set), then it SHOULD verify that all Components in the
   Component Set are specified by one update, that is the manifest:

   1.  has sufficient permissions imparted by its signatures

   2.  specifies a digest and a payload for every Component in the
       Component Set.

6.2.1.  Minimizing Signature Verifications

   Signature verification can be energy and time expensive on a
   constrained device.  MAC verification is typically unaffected by
   these concerns.  A Recipient MAY choose to parse and execute only the
   SUIT_Common section of the manifest prior to signature verification,
   if all of the below apply:

   *  The Authentication Block contains a COSE_Sign_Tagged or
      COSE_Sign1_Tagged

   *  The Recipient receives manifests over an unauthenticated channel,
      exposing it to more inauthentic or incompatible manifests, and

   *  The Recipient has a power budget that makes signature verification
      undesirable

   When executing Common prior to authenticity validation, the Manifest
   Processor MUST first evaluate the integrity of the manifest using the
   SUIT_Digest present in the authentication block.

   The guidelines in Creating Manifests (Section 7) require that the
   common section contains the applicability checks, so this section is
   sufficient for applicability verification.  The parser MUST restrict
   acceptable commands to conditions and the following directives:
   Override Parameters, Set Parameters, Try Each, and Run Sequence ONLY.
   The manifest parser MUST NOT execute any command with side-effects
   outside the parser (for example, Run, Copy, Swap, or Fetch commands)
   prior to authentication and any such command MUST Abort.  The Common
   Sequence MUST be executed again, in its entirety, after authenticity
   validation.

   A Recipient MAY rely on network infrastructure to filter inapplicable
   manifests.

6.3.  Interpreter Fundamental Properties

   The interpreter has a small set of design goals:

   1.  Executing an update MUST either result in an error, or a
       verifiably correct system state.

   2.  Executing a Trusted Invocation MUST either result in an error, or
       an invoked image.

   3.  Executing the same manifest on multiple Recipients MUST result in
       the same system state.

   NOTE: when using A/B images, the manifest functions as two (or more)
   logical manifests, each of which applies to a system in a particular
   starting state.  With that provision, design goal 3 holds.

6.4.  Abstract Machine Description

   The heart of the manifest is the list of commands, which are
   processed by a Manifest Processor--a form of interpreter.  This
   Manifest Processor can be modeled as a simple abstract machine.  This
   machine consists of several data storage locations that are modified
   by commands.

   There are two types of commands, namely those that modify state
   (directives) and those that perform tests (conditions).  Parameters
   are used as the inputs to commands.  Some directives offer control
   flow operations.  Directives target a specific component.  A
   component is a unit of code or data that can be targeted by an
   update.  Components are identified by Component Identifiers, but
   referenced in commands by Component Index; Component Identifiers are
   arrays of binary strings and a Component Index is an index into the
   array of Component Identifiers.

   Conditions MUST NOT have any side-effects other than informing the
   interpreter of success or failure.  The Interpreter does not Abort if
   the Soft Failure flag (Section 8.4.8.14) is set when a Condition
   reports failure.

   Directives MAY have side-effects in the parameter table, the
   interpreter state, or the current component.  The Interpreter MUST
   Abort if a Directive reports failure regardless of the Soft Failure
   flag.

   To simplify the logic describing the command semantics, the object
   "current" is used.  It represents the component identified by the
   Component Index:

   current := components\[component-index\]

   As a result, Set Component Index is described as current :=
   components[arg].

   The following table describes the behavior of each command. "params"
   represents the parameters for the current component.  Most commands
   operate on a component.

    +=========================+======================================+
    | Command Name            | Semantic of the Operation            |
    +=========================+======================================+
    | Check Vendor Identifier | assert(binary-match(current,         |
    |                         | current.params[vendor-id]))          |
    +-------------------------+--------------------------------------+
    | Check Class Identifier  | assert(binary-match(current,         |
    |                         | current.params[class-id]))           |
    +-------------------------+--------------------------------------+
    | Verify Image            | assert(binary-match(digest(current), |
    |                         | current.params[digest]))             |
    +-------------------------+--------------------------------------+
    | Set Component Index     | current := components[arg]           |
    +-------------------------+--------------------------------------+
    | Override Parameters     | current.params[k] := v for-each k,v  |
    |                         | in arg                               |
    +-------------------------+--------------------------------------+
    | Set Parameters          | current.params[k] := v if not k in   |
    |                         | params for-each k,v in arg           |
    +-------------------------+--------------------------------------+
    | Run                     | run(current)                         |
    +-------------------------+--------------------------------------+
    | Fetch                   | store(current,                       |
    |                         | fetch(current.params[uri]))          |
    +-------------------------+--------------------------------------+
    | Use Before              | assert(now() < arg)                  |
    +-------------------------+--------------------------------------+
    | Check Component Slot    | assert(current.slot-index == arg)    |
    +-------------------------+--------------------------------------+
    | Check Device Identifier | assert(binary-match(current,         |
    |                         | current.params[device-id]))          |
    +-------------------------+--------------------------------------+
    | Abort                   | assert(0)                            |
    +-------------------------+--------------------------------------+
    | Try Each                | try-each-done if exec(seq) is not    |
    |                         | error for-each seq in arg            |
    +-------------------------+--------------------------------------+
    | Copy                    | store(current, current.params[src-   |
    |                         | component])                          |
    +-------------------------+--------------------------------------+
    | Swap                    | swap(current, current.params[src-    |
    |                         | component])                          |
    +-------------------------+--------------------------------------+
    | Run Sequence            | exec(arg)                            |
    +-------------------------+--------------------------------------+
    | Run with Arguments      | run(current, arg)                    |
    +-------------------------+--------------------------------------+

                                 Table 1

6.5.  Special Cases of Component Index

   Component Index can take on one of three types:

   1.  Integer

   2.  Array of integers

   3.  True

   Integers MUST always be supported by Set Component Index.  Arrays of
   integers MUST be supported by Set Component Index if the Recipient
   supports 3 or more components.  True MUST be supported by Set
   Component Index if the Recipient supports 2 or more components.  Each
   of these operates on the list of components declared in the manifest.

   Integer indices are the default case as described in the previous
   section.  An array of integers represents a list of the components
   (Set Component Index) to which each subsequent command applies.  The
   value True replaces the list of component indices with the full list
   of components, as defined in the manifest.

   When a command is executed, it either 1. operates on the component
   identified by the component index if that index is an integer, or 2.
   it operates on each component identified by an array of indicies, or
   3. it operates on every component if the index is the boolean True.
   This is described by the following pseudocode:

   if component-index is true:
       current-list = components
   else if component-index is array:
       current-list = [ components[idx] for idx in component-index ]
   else:
       current-list = [ components[component-index] ]
   for current in current-list:
       cmd(current)

   Try Each and Run Sequence are affected in the same way as other
   commands: they are invoked once for each possible Component.  This
   means that the sequences that are arguments to Try Each and Run
   Sequence are NOT invoked with Component Index = True, nor are they
   invoked with array indices.  They are only invoked with integer
   indices.  The interpreter loops over the whole sequence, setting the
   Component Index to each index in turn.

6.6.  Serialized Processing Interpreter

   In highly constrained devices, where storage for parameters is
   limited, the manifest processor MAY handle one component at a time,
   traversing the manifest tree once for each listed component.  In this
   mode, the interpreter ignores any commands executed while the
   component index is not the current component.  This reduces the
   overall volatile storage required to process the update so that the
   only limit on number of components is the size of the manifest.
   However, this approach requires additional processing power.

   In order to operate in this mode, the manifest processor loops on
   each section for every supported component, simply ignoring commands
   when the current component is not selected.

   When a serialized Manifest Processor encounters a component index of
   True, it does not ignore any commands.  It applies them to the
   current component on each iteration.

6.7.  Parallel Processing Interpreter

   Advanced Recipients MAY make use of the Strict Order parameter and
   enable parallel processing of some Command Sequences, or it may
   reorder some Command Sequences.  To perform parallel processing, once
   the Strict Order parameter is set to False, the Recipient may issue
   each or every command concurrently until the Strict Order parameter
   is returned to True or the Command Sequence ends.  Then, it waits for
   all issued commands to complete before continuing processing of
   commands.  To perform out-of-order processing, a similar approach is
   used, except the Recipient consumes all commands after the Strict
   Order parameter is set to False, then it sorts these commands into
   its preferred order, invokes them all, then continues processing.

   When the manifest processor encounters any of these scenarios the
   parallel processing MUST halt until all issued commands have
   completed:

   *  Set Parameters.

   *  Override Parameters.

   *  Set Strict Order = True.

   *  Set Component Index.

   To perform more useful parallel operations, a manifest author may
   collect sequences of commands in a Run Sequence command.  Then, each
   of these sequences MAY be run in parallel.  Each sequence defaults to
   Strict Order = True.  To isolate each sequence from each other
   sequence, each sequence MUST begin with a Set Component Index
   directive with the following exception: when the index is either True
   or an array of indices, the Set Component Index is implied.  Any
   further Set Component Index directives MUST cause an Abort.  This
   allows the interpreter that issues Run Sequence commands to check
   that the first element is correct, then issue the sequence to a
   parallel execution context to handle the remainder of the sequence.

7.  Creating Manifests

   Manifests are created using tools for constructing COSE structures,
   calculating cryptographic values and compiling desired system state
   into a sequence of operations required to achieve that state.  The
   process of constructing COSE structures and the calculation of
   cryptographic values is covered in [RFC8152].

   Compiling desired system state into a sequence of operations can be
   accomplished in many ways.  Several templates are provided below to
   cover common use-cases.  These templates can be combined to produce
   more complex behavior.

   The author MUST ensure that all parameters consumed by a command are
   set prior to invoking that command.  Where Component Index = True,
   this means that the parameters consumed by each command MUST have
   been set for each Component.

   This section details a set of templates for creating manifests.
   These templates explain which parameters, commands, and orders of
   commands are necessary to achieve a stated goal.

   NOTE: On systems that support only a single component, Set Component
   Index has no effect and can be omitted.

   NOTE: *A digest MUST always be set using Override Parameters.*

7.1.  Compatibility Check Template

   The goal of the compatibility check template ensure that Recipients
   only install compatible images.

   In this template all information is contained in the common sequence
   and the following sequence of commands is used:

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Override Parameters directive (see Section 8.4.10.3) for Vendor ID
      and Class ID (see Section 8.4.8)

   *  Check Vendor Identifier condition (see Section 8.4.8.2)

   *  Check Class Identifier condition (see Section 8.4.8.2)

7.2.  Trusted Invocation Template

   The goal of the Trusted Invocation template is to ensure that only
   authorized code is invoked; such as in Secure Boot or when a Trusted
   Application is loaded into a TEE.

   The following commands are placed into the common sequence:

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Override Parameters directive (see Section 8.4.10.3) for Image
      Digest and Image Size (see Section 8.4.8)

   The system validation sequence contains the following commands:

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Check Image Match condition (see Section 8.4.9.2)

   Then, the run sequence contains the following commands:

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Run directive (see Section 8.4.10.7)

7.3.  Component Download Template

   The goal of the Component Download template is to acquire and store
   an image.

   The following commands are placed into the common sequence:

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Override Parameters directive (see Section 8.4.10.3) for Image
      Digest and Image Size (see Section 8.4.8)

   Then, the install sequence contains the following commands:

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Override Parameters directive (see Section 8.4.10.3) for URI (see
      Section 8.4.8.9)

   *  Fetch directive (see Section 8.4.10.4)

   *  Check Image Match condition (see Section 8.4.9.2)

   The Fetch directive needs the URI parameter to be set to determine
   where the image is retrieved from.  Additionally, the destination of
   where the component shall be stored has to be configured.  The URI is
   configured via the Set Parameters directive while the destination is
   configured via the Set Component Index directive.

7.4.  Install Template

   The goal of the Install template is to use an image already stored in
   an identified component to copy into a second component.

   This template is typically used with the Component Download template,
   however a modification to that template is required: the Component
   Download operations are moved from the Payload Install sequence to
   the Payload Fetch sequence.

   Then, the install sequence contains the following commands:

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Override Parameters directive (see Section 8.4.10.3) for Source
      Component (see Section 8.4.8.10)

   *  Copy directive (see Section 8.4.10.5)

   *  Check Image Match condition (see Section 8.4.9.2)

7.5.  Integrated Payload Template

   The goal of the Integrated Payload template is to install a payload
   that is included in the manifest envelope.  It is identical to the
   Component Download template (Section 7.3).

   An implementer MAY choose to place a payload in the envelope of a
   manifest.  The payload envelope key MUST be a string.  The payload
   MUST be serialized in a bstr element.

   The URI for a payload enclosed in this way MAY be expressed as a
   fragment-only reference, as defined in [RFC3986], Section 4.4.

   A distributor MAY choose to pre-fetch a payload and add it to the
   manifest envelope, using the URI as the key.

7.6.  Load from Nonvolatile Storage Template

   The goal of the Load from Nonvolatile Storage template is to load an
   image from a non-volatile component into a volatile component, for
   example loading a firmware image from external Flash into RAM.

   The following commands are placed into the load sequence:

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Override Parameters directive (see Section 8.4.10.3) for Source
      Component (see Section 8.4.8)

   *  Copy directive (see Section 8.4.10.5)

   As outlined in Section 6.4, the Copy directive needs a source and a
   destination to be configured.  The source is configured via Component
   Index (with the Set Parameters directive) and the destination is
   configured via the Set Component Index directive.

7.7.  A/B Image Template

   The goal of the A/B Image Template is to acquire, validate, and
   invoke one of two images, based on a test.

   The following commands are placed in the common block:

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Try Each

      -  First Sequence:

         o  Override Parameters directive (see Section 8.4.10.3,
            Section 8.4.8) for Slot A

         o  Check Slot Condition (see Section 8.4.9.3)

         o  Override Parameters directive (see Section 8.4.10.3) for
            Image Digest A and Image Size A (see Section 8.4.8)

      -  Second Sequence:

         o  Override Parameters directive (see Section 8.4.10.3,
            Section 8.4.8) for Slot B

         o  Check Slot Condition (see Section 8.4.9.3)

         o  Override Parameters directive (see Section 8.4.10.3) for
            Image Digest B and Image Size B (see Section 8.4.8)

   The following commands are placed in the fetch block or install block

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Try Each

      -  First Sequence:

         o  Override Parameters directive (see Section 8.4.10.3,
            Section 8.4.8) for Slot A

         o  Check Slot Condition (see Section 8.4.9.3)

         o  Set Parameters directive (see Section 8.4.10.3) for URI A
            (see Section 8.4.8)

      -  Second Sequence:

         o  Override Parameters directive (see Section 8.4.10.3,
            Section 8.4.8) for Slot B

         o  Check Slot Condition (see Section 8.4.9.3)

         o  Set Parameters directive (see Section 8.4.10.3) for URI B
            (see Section 8.4.8)

   *  Fetch

   If Trusted Invocation (Section 7.2) is used, only the run sequence is
   added to this template, since the common sequence is populated by
   this template:

   *  Set Component Index directive (see Section 8.4.10.1)

   *  Try Each

      -  First Sequence:

         o  Override Parameters directive (see Section 8.4.10.3,
            Section 8.4.8) for Slot A

         o  Check Slot Condition (see Section 8.4.9.3)

      -  Second Sequence:

         o  Override Parameters directive (see Section 8.4.10.3,
            Section 8.4.8) for Slot B

         o  Check Slot Condition (see Section 8.4.9.3)

   *  Run

   NOTE: Any test can be used to select between images, Check Slot
   Condition is used in this template because it is a typical test for
   execute-in-place devices.

8.  Metadata Structure

   The metadata for SUIT updates is composed of several primary
   constituent parts: the Envelope, Authentication Information,
   Manifest, and Severable Elements.

   For a diagram of the metadata structure, see Section 5.

8.1.  Encoding Considerations

   The map indices in the envelope encoding are reset to 1 for each map
   within the structure.  This is to keep the indices as small as
   possible.  The goal is to keep the index objects to single bytes
   (CBOR positive integers 1-23).

   Wherever enumerations are used, they are started at 1.  This allows
   detection of several common software errors that are caused by
   uninitialized variables.  Positive numbers in enumerations are
   reserved for IANA registration.  Negative numbers are used to
   identify application-specific values, as described in Section 11.

   All elements of the envelope must be wrapped in a bstr to minimize
   the complexity of the code that evaluates the cryptographic integrity
   of the element and to ensure correct serialization for integrity and
   authenticity checks.

8.2.  Envelope

   The Envelope contains each of the other primary constituent parts of
   the SUIT metadata.  It allows for modular processing of the manifest
   by ordering components in the expected order of processing.

   The Envelope is encoded as a CBOR Map. Each element of the Envelope
   is enclosed in a bstr, which allows computation of a message digest
   against known bounds.

8.3.  Authenticated Manifests

   The suit-authentication-wrapper contains a list containing a SUIT
   Digest Container (see Section 10) and one or more cryptographic
   authentication wrappers for the Manifest.  These blocks are
   implemented as COSE_Mac_Tagged or COSE_Sign_Tagged structures with
   null payloads, indicating that the payload to be used is the SUIT
   Digest Container.  This enables modular processing of the manifest.
   The COSE_Mac_Tagged and COSE_Sign_Tagged blocks are described in RFC
   8152 [RFC8152].  The suit-authentication-wrapper MUST come before any
   element in the SUIT_Envelope, regardless of canonical encoding of
   CBOR.  All validators MUST reject any SUIT_Envelope that begins with
   any element other than a suit-authentication-wrapper (NOTE: key
   delegation MAY relax this requirement to include a delegation
   structure as well).

   A SUIT_Envelope that has not had authentication information added
   MUST still contain the suit-authentication-wrapper element, but the
   content MUST be a list containing only the SUIT_Digest.

   A signing application MUST verify the suit-manifest element against
   the SUIT_Digest prior to signing.

8.4.  Manifest

   The manifest contains:

   *  a version number (see Section 8.4.1)

   *  a sequence number (see Section 8.4.2)

   *  a reference URI (see Section 8.4.3)

   *  a common structure with information that is shared between command
      sequences (see Section 8.4.5)

   *  one or more lists of commands that the Recipient should perform
      (see Section 8.4.6)

   *  a reference to the full manifest (see Section 8.4.3)

   *  human-readable text describing the manifest found in the
      SUIT_Envelope (see Section 8.4.4)

   The Text section, or any Command Sequence of the Update Procedure
   (Image Fetch, Image Installation) can be either a CBOR structure or a
   SUIT_Digest.  In each of these cases, the SUIT_Digest provides for a
   severable element.  Severable elements are RECOMMENDED to implement.
   In particular, the human-readable text SHOULD be severable, since
   most useful text elements occupy more space than a SUIT_Digest, but
   are not needed by the Recipient.  Because SUIT_Digest is a CBOR Array
   and each severable element is a CBOR bstr, it is straight-forward for
   a Recipient to determine whether an element has been severed.  The
   key used for a severable element is the same in the SUIT_Manifest and
   in the SUIT_Envelope so that a Recipient can easily identify the
   correct data in the envelope.  See Section 8.4.11 for more detail.

8.4.1.  suit-manifest-version

   The suit-manifest-version indicates the version of serialization used
   to encode the manifest.  Version 1 is the version described in this
   document. suit-manifest-version is REQUIRED to implement.

8.4.2.  suit-manifest-sequence-number

   The suit-manifest-sequence-number is a monotonically increasing anti-
   rollback counter.  Each Recipient MUST reject any manifest that has a
   sequence number lower than its current sequence number.  For
   convenience, an implementer MAY use a UTC timestamp in seconds as the
   sequence number. suit-manifest-sequence-number is REQUIRED to
   implement.

8.4.3.  suit-reference-uri

   suit-reference-uri is a text string that encodes a URI where a full
   version of this manifest can be found.  This is convenient for
   allowing management systems to show the severed elements of a
   manifest when this URI is reported by a Recipient after installation.

8.4.4.  suit-text

   suit-text SHOULD be a severable element. suit-text is a map
   containing two different types of pair:

   *  integer => text

   *  SUIT_Component_Identifier => map

   Each SUIT_Component_Identifier => map entry contains a map of integer
   => text values.  All SUIT_Component_Identifiers present in suit-text
   MUST also be present in suit-common (Section 8.4.5).

   suit-text contains all the human-readable information that describes
   any and all parts of the manifest, its payload(s) and its
   resource(s).  The text section is typically severable, allowing
   manifests to be distributed without the text, since end-nodes do not
   require text.  The meaning of each field is described below.

   Each section MAY be present.  If present, each section MUST be as
   described.  Negative integer IDs are reserved for application-
   specific text values.

   The following table describes the text fields available in suit-text:

   +================================+==================================+
   | CDDL Structure                 | Description                      |
   +================================+==================================+
   | suit-text-manifest-description | Free text description of         |
   |                                | the manifest                     |
   +--------------------------------+----------------------------------+
   | suit-text-update-description   | Free text description of         |
   |                                | the update                       |
   +--------------------------------+----------------------------------+
   | suit-text-manifest-json-source | The JSON-formatted document      |
   |                                | that was used to create the      |
   |                                | manifest                         |
   +--------------------------------+----------------------------------+
   | suit-text-manifest-yaml-source | The YAML ([YAML])-formatted      |
   |                                | document that was used to        |
   |                                | create the manifest              |
   +--------------------------------+----------------------------------+

                                  Table 2

   The following table describes the text fields available in each map
   identified by a SUIT_Component_Identifier.

    +=================================+===============================+
    | CDDL Structure                  | Description                   |
    +=================================+===============================+
    | suit-text-vendor-name           | Free text vendor name         |
    +---------------------------------+-------------------------------+
    | suit-text-model-name            | Free text model name          |
    +---------------------------------+-------------------------------+
    | suit-text-vendor-domain         | The domain used to create the |
    |                                 | vendor-id condition           |
    +---------------------------------+-------------------------------+
    | suit-text-model-info            | The information used to       |
    |                                 | create the class-id condition |
    +---------------------------------+-------------------------------+
    | suit-text-component-description | Free text description of each |
    |                                 | component in the manifest     |
    +---------------------------------+-------------------------------+
    | suit-text-component-version     | A free text representation of |
    |                                 | the component version         |
    +---------------------------------+-------------------------------+

                                  Table 3

   suit-text is OPTIONAL to implement.

8.4.5.  suit-common

   suit-common encodes all the information that is shared between each
   of the command sequences, including: suit-components, and suit-
   common-sequence. suit-common is REQUIRED to implement.

   suit-components is a list of SUIT_Component_Identifier
   (Section 8.4.5.1) blocks that specify the component identifiers that
   will be affected by the content of the current manifest. suit-
   components is REQUIRED to implement.

   suit-common-sequence is a SUIT_Command_Sequence to execute prior to
   executing any other command sequence.  Typical actions in suit-
   common-sequence include setting expected Recipient identity and image
   digests when they are conditional (see Section 8.4.10.2 and
   Section 7.7 for more information on conditional sequences). suit-
   common-sequence is RECOMMENDED to implement.  It is REQUIRED if the
   optimizations described in Section 6.2.1 will be used.  Whenever a
   parameter or Try Each command is required by more than one Command
   Sequence, placing that parameter or command in suit-common-sequence
   results in a smaller encoding.

8.4.5.1.  SUIT_Component_Identifier

   A component is a unit of code or data that can be targeted by an
   update.  To facilitate composite devices, components are identified
   by a list of CBOR byte strings, which allows construction of
   hierarchical component structures.  Components are identified by
   Component Identifiers, but referenced in commands by Component Index;
   Component Identifiers are arrays of binary strings and a Component
   Index is an index into the array of Component Identifiers.

   A Component Identifier can be trivial, such as the simple array
   [h'00'].  It can also represent a filesystem path by encoding each
   segment of the path as an element in the list.  For example, the path
   "/usr/bin/env" would encode to ['usr','bin','env'].

   This hierarchical construction allows a component identifier to
   identify any part of a complex, multi-component system.

8.4.6.  SUIT_Command_Sequence

   A SUIT_Command_Sequence defines a series of actions that the
   Recipient MUST take to accomplish a particular goal.  These goals are
   defined in the manifest and include:

   1.  Payload Fetch: suit-payload-fetch is a SUIT_Command_Sequence to
       execute in order to obtain a payload.  Some manifests may include
       these actions in the suit-install section instead if they operate
       in a streaming installation mode.  This is particularly relevant
       for constrained devices without any temporary storage for staging
       the update. suit-payload-fetch is OPTIONAL to implement.

   2.  Payload Installation: suit-install is a SUIT_Command_Sequence to
       execute in order to install a payload.  Typical actions include
       verifying a payload stored in temporary storage, copying a staged
       payload from temporary storage, and unpacking a payload. suit-
       install is OPTIONAL to implement.

   3.  Image Validation: suit-validate is a SUIT_Command_Sequence to
       execute in order to validate that the result of applying the
       update is correct.  Typical actions involve image validation.
       suit-validate is REQUIRED to implement.

   4.  Image Loading: suit-load is a SUIT_Command_Sequence to execute in
       order to prepare a payload for execution.  Typical actions
       include copying an image from permanent storage into RAM,
       optionally including actions such as decryption or decompression.
       suit-load is OPTIONAL to implement.

   5.  Run or Boot: suit-run is a SUIT_Command_Sequence to execute in
       order to run an image. suit-run typically contains a single
       instruction: the "run" directive. suit-run is OPTIONAL to
       implement.

   Goals 1,2 form the Update Procedure.  Goals 4,5,6 form the Invocation
   Procedure.

   Each Command Sequence follows exactly the same structure to ensure
   that the parser is as simple as possible.

   Lists of commands are constructed from two kinds of element:

   1.  Conditions that MUST be true and any failure is treated as a
       failure of the update/load/invocation

   2.  Directives that MUST be executed.

   Each condition is composed of:

   1.  A command code identifier

   2.  A SUIT_Reporting_Policy (Section 8.4.7)

   Each directive is composed of:

   1.  A command code identifier

   2.  An argument block or a SUIT_Reporting_Policy (Section 8.4.7)

   Argument blocks are consumed only by flow-control directives:

   *  Set Component Index

   *  Set/Override Parameters

   *  Try Each

   *  Run Sequence

   Reporting policies provide a hint to the manifest processor of
   whether to add the success or failure of a command to any report that
   it generates.

   Many conditions and directives apply to a given component, and these
   generally grouped together.  Therefore, a special command to set the
   current component index is provided.  This index is a numeric index
   into the Component Identifier table defined at the beginning of the
   manifest.

   To facilitate optional conditions, a special directive, suit-
   directive-try-each (Section 8.4.10.2), is provided.  It runs several
   new lists of conditions/directives, one after another, that are
   contained as an argument to the directive.  By default, it assumes
   that a failure of a condition should not indicate a failure of the
   update/invocation, but a parameter is provided to override this
   behavior.  See suit-parameter-soft-failure (Section 8.4.8.14).

8.4.7.  Reporting Policy

   To facilitate construction of Reports that describe the success or
   failure of a given Procedure, each command is given a Reporting
   Policy.  This is an integer bitfield that follows the command and
   indicates what the Recipient should do with the Record of executing
   the command.  The options are summarized in the table below.

    +=============================+==================================+
    | Policy                      | Description                      |
    +=============================+==================================+
    | suit-send-record-on-success | Record when the command succeeds |
    +-----------------------------+----------------------------------+
    | suit-send-record-on-failure | Record when the command fails    |
    +-----------------------------+----------------------------------+
    | suit-send-sysinfo-success   | Add system information when the  |
    |                             | command succeeds                 |
    +-----------------------------+----------------------------------+
    | suit-send-sysinfo-failure   | Add system information when the  |
    |                             | command fails                    |
    +-----------------------------+----------------------------------+

                                 Table 4

   Any or all of these policies may be enabled at once.

   At the completion of each command, a Manifest Processor MAY forward
   information about the command to a Reporting Engine, which is
   responsible for reporting boot or update status to a third party.
   The Reporting Engine is entirely implementation-defined, the
   reporting policy simply facilitates the Reporting Engine's interface
   to the SUIT Manifest Processor.

   The information elements provided to the Reporting Engine are:

   *  The reporting policy

   *  The result of the command

   *  The values of parameters consumed by the command

   *  The system information consumed by the command

   Together, these elements are called a Record.  A group of Records is
   a Report.

   If the component index is set to True or an array when a command is
   executed with a non-zero reporting policy, then the Reporting Engine
   MUST receive one Record for each Component, in the order expressed in
   the Components list or the component index array.

   This specification does not define a particular format of Records or
   Reports.  This specification only defines hints to the Reporting
   Engine for which Records it should aggregate into the Report.  The
   Reporting Engine MAY choose to ignore these hints and apply its own
   policy instead.

   When used in a Invocation Procedure, the report MAY form the basis of
   an attestation report.  When used in an Update Process, the report
   MAY form the basis for one or more log entries.

8.4.8.  SUIT_Parameters

   Many conditions and directives require additional information.  That
   information is contained within parameters that can be set in a
   consistent way.  This allows reuse of parameters between commands,
   thus reducing manifest size.

   Most parameters are scoped to a specific component.  This means that
   setting a parameter for one component has no effect on the parameters
   of any other component.  The only exceptions to this are two Manifest
   Processor parameters: Strict Order and Soft Failure.

   The defined manifest parameters are described below.

   +==============+==================================+=================+
   | Name         | CDDL Structure                   | Reference       |
   +==============+==================================+=================+
   | Vendor ID    | suit-parameter-vendor-identifier | Section 8.4.8.3 |
   +--------------+----------------------------------+-----------------+
   | Class ID     | suit-parameter-class-identifier  | Section 8.4.8.4 |
   +--------------+----------------------------------+-----------------+
   | Device ID    | suit-parameter-device-identifier | Section 8.4.8.5 |
   +--------------+----------------------------------+-----------------+
   | Image        | suit-parameter-image-digest      | Section 8.4.8.6 |
   | Digest       |                                  |                 |
   +--------------+----------------------------------+-----------------+
   | Image        | suit-parameter-image-size        | Section 8.4.8.7 |
   | Size         |                                  |                 |
   +--------------+----------------------------------+-----------------+
   | Component    | suit-parameter-component-slot    | Section 8.4.8.8 |
   | Slot         |                                  |                 |
   +--------------+----------------------------------+-----------------+
   | URI          | suit-parameter-uri               | Section 8.4.8.9 |
   +--------------+----------------------------------+-----------------+
   | Source       | suit-parameter-source-component  | Section         |
   | Component    |                                  | 8.4.8.10        |
   +--------------+----------------------------------+-----------------+
   | Run Args     | suit-parameter-run-args          | Section         |
   |              |                                  | 8.4.8.11        |
   +--------------+----------------------------------+-----------------+
   | Fetch        | suit-parameter-fetch-arguments   | Section         |
   | Arguments    |                                  | 8.4.8.12        |
   +--------------+----------------------------------+-----------------+
   | Strict       | suit-parameter-strict-order      | Section         |
   | Order        |                                  | 8.4.8.13        |
   +--------------+----------------------------------+-----------------+
   | Soft         | suit-parameter-soft-failure      | Section         |
   | Failure      |                                  | 8.4.8.14        |
   +--------------+----------------------------------+-----------------+
   | Custom       | suit-parameter-custom            | Section         |
   |              |                                  | 8.4.8.15        |
   +--------------+----------------------------------+-----------------+

                                  Table 5

   CBOR-encoded object parameters are still wrapped in a bstr.  This is
   because it allows a parser that is aggregating parameters to
   reference the object with a single pointer and traverse it without
   understanding the contents.  This is important for modularization and
   division of responsibility within a pull parser.  The same
   consideration does not apply to Directives because those elements are
   invoked with their arguments immediately.

8.4.8.1.  CBOR PEN UUID Namespace Identifier

   The CBOR PEN UUID Namespace Identifier is constructed as follows:

   It uses the OID Namespace as a starting point, then uses the CBOR OID
   encoding for the IANA PEN OID (1.3.6.1.4.1):

   D8 6F                # tag(111)
      45                # bytes(5)
   # Absolute OID encoding of IANA Private Enterprise Number:
   #    1.3. 6. 1. 4. 1
         2B 06 01 04 01 # X.690 Clause 8.19

   Computing a type 5 UUID from these produces:

   NAMESPACE_CBOR_PEN = UUID5(NAMESPACE_OID, h'D86F452B06010401')
   NAMESPACE_CBOR_PEN = 47fbdabb-f2e4-55f0-bb39-3620c2f6df4e

8.4.8.2.  Constructing UUIDs

   Several conditions use identifiers to determine whether a manifest
   matches a given Recipient or not.  These identifiers are defined to
   be RFC 4122 [RFC4122] UUIDs.  These UUIDs are not human-readable and
   are therefore used for machine-based processing only.

   A Recipient MAY match any number of UUIDs for vendor or class
   identifier.  This may be relevant to physical or software modules.
   For example, a Recipient that has an OS and one or more applications
   might list one Vendor ID for the OS and one or more additional Vendor
   IDs for the applications.  This Recipient might also have a Class ID
   that must be matched for the OS and one or more Class IDs for the
   applications.

   Identifiers are used for compatibility checks.  They MUST NOT be used
   as assertions of identity.  They are evaluated by identifier
   conditions (Section 8.4.9.1).

   A more complete example: Imagine a device has the following physical
   components: 1.  A host MCU 2.  A WiFi module

   This same device has three software modules: 1.  An operating system
   2.  A WiFi module interface driver 3.  An application

   Suppose that the WiFi module's firmware has a proprietary update
   mechanism and doesn't support manifest processing.  This device can
   report four class IDs:

   1.  Hardware model/revision
   2.  OS

   3.  WiFi module model/revision

   4.  Application

   This allows the OS, WiFi module, and application to be updated
   independently.  To combat possible incompatibilities, the OS class ID
   can be changed each time the OS has a change to its API.

   This approach allows a vendor to target, for example, all devices
   with a particular WiFi module with an update, which is a very
   powerful mechanism, particularly when used for security updates.

   UUIDs MUST be created according to RFC 4122 [RFC4122].  UUIDs SHOULD
   use versions 3, 4, or 5, as described in RFC4122.  Versions 1 and 2
   do not provide a tangible benefit over version 4 for this
   application.

   The RECOMMENDED method to create a vendor ID is:

   Vendor ID = UUID5(DNS_PREFIX, vendor domain name)

   If the Vendor ID is a UUID, the RECOMMENDED method to create a Class
   ID is:

   Class ID = UUID5(Vendor ID, Class-Specific-Information)

   If the Vendor ID is a CBOR PEN (see Section 8.4.8.3), the RECOMMENDED
   method to create a Class ID is:

   Class ID = UUID5(
       UUID5(NAMESPACE_CBOR_PEN, CBOR_PEN),
       Class-Specific-Information)

   Class-specific-information is composed of a variety of data, for
   example:

   *  Model number.

   *  Hardware revision.

   *  Bootloader version (for immutable bootloaders).

8.4.8.3.  suit-parameter-vendor-identifier

   suit-parameter-vendor-identifier may be presented in one of two ways:

   *  A Private Enterprise Number

   *  A byte string containing a UUID ([RFC4122])

   Private Enterprise Numbers are encoded as a relative OID, according
   to the definition in [I-D.ietf-cbor-tags-oid].  All PENs are relative
   to the IANA PEN: 1.3.6.1.4.1.

8.4.8.4.  suit-parameter-class-identifier

   A RFC 4122 UUID representing the class of the device or component.
   The UUID is encoded as a 16 byte bstr, containing the raw bytes of
   the UUID.  It MUST be constructed as described in Section 8.4.8.2

8.4.8.5.  suit-parameter-device-identifier

   A RFC 4122 UUID representing the specific device or component.  The
   UUID is encoded as a 16 byte bstr, containing the raw bytes of the
   UUID.  It MUST be constructed as described in Section 8.4.8.2

8.4.8.6.  suit-parameter-image-digest

   A fingerprint computed over the component itself, encoded in the
   SUIT_Digest Section 10 structure.  The SUIT_Digest is wrapped in a
   bstr, as required in Section 8.4.8.

8.4.8.7.  suit-parameter-image-size

   The size of the firmware image in bytes.  This size is encoded as a
   positive integer.

8.4.8.8.  suit-parameter-component-slot

   This parameter sets the slot index of a component.  Some components
   support multiple possible Slots (offsets into a storage area).  This
   parameter describes the intended Slot to use, identified by its index
   into the component's storage area.  This slot MUST be encoded as a
   positive integer.

8.4.8.9.  suit-parameter-uri

   A URI Reference ([RFC3986]) from which to fetch a resource, encoded
   as a text string.  CBOR Tag 32 is not used because the meaning of the
   text string is unambiguous in this context.

8.4.8.10.  suit-parameter-source-component

   This parameter sets the source component to be used with either suit-
   directive-copy (Section 8.4.10.5) or with suit-directive-swap
   (Section 8.4.10.8).  The current Component, as set by suit-directive-
   set-component-index defines the destination, and suit-parameter-
   source-component defines the source.

8.4.8.11.  suit-parameter-run-args

   This parameter contains an encoded set of arguments for suit-
   directive-run (Section 8.4.10.6).  The arguments MUST be provided as
   an implementation-defined bstr.

8.4.8.12.  suit-parameter-fetch-arguments

   An implementation-defined set of arguments to suit-directive-fetch
   (Section 8.4.10.4).  Arguments are encoded in a bstr.

8.4.8.13.  suit-parameter-strict-order

   The Strict Order Parameter allows a manifest to govern when
   directives can be executed out-of-order.  This allows for systems
   that have a sensitivity to order of updates to choose the order in
   which they are executed.  It also allows for more advanced systems to
   parallelize their handling of updates.  Strict Order defaults to
   True.  It MAY be set to False when the order of operations does not
   matter.  When arriving at the end of a command sequence, ALL commands
   MUST have completed, regardless of the state of
   SUIT_Parameter_Strict_Order.  If SUIT_Parameter_Strict_Order is
   returned to True, ALL preceding commands MUST complete before the
   next command is executed.

   See Section 6.7 for behavioral description of Strict Order.

8.4.8.14.  suit-parameter-soft-failure

   When executing a command sequence inside suit-directive-try-each
   (Section 8.4.10.2) or suit-directive-run-sequence (Section 8.4.10.7)
   and a condition failure occurs, the manifest processor aborts the
   sequence.  For suit-directive-try-each, if Soft Failure is True, the
   next sequence in Try Each is invoked, otherwise suit-directive-try-
   each fails with the condition failure code.  In suit-directive-run-
   sequence, if Soft Failure is True the suit-directive-run-sequence
   simply halts with no side-effects and the Manifest Processor
   continues with the following command, otherwise, the suit-directive-
   run-sequence fails with the condition failure code.

   suit-parameter-soft-failure is scoped to the enclosing
   SUIT_Command_Sequence.  Its value is discarded when
   SUIT_Command_Sequence terminates.  It MUST NOT be set outside of
   suit-directive-try-each or suit-directive-run-sequence.

   When suit-directive-try-each is invoked, Soft Failure defaults to
   True.  An Update Author may choose to set Soft Failure to False if
   they require a failed condition in a sequence to force an Abort.

   When suit-directive-run-sequence is invoked, Soft Failure defaults to
   False.  An Update Author may choose to make failures soft within a
   suit-directive-run-sequence.

8.4.8.15.  suit-parameter-custom

   This parameter is an extension point for any proprietary, application
   specific conditions and directives.  It MUST NOT be used in the
   common sequence.  This effectively scopes each custom command to a
   particular Vendor Identifier/Class Identifier pair.

8.4.9.  SUIT_Condition

   Conditions are used to define mandatory properties of a system in
   order for an update to be applied.  They can be pre-conditions or
   post-conditions of any directive or series of directives, depending
   on where they are placed in the list.  All Conditions specify a
   Reporting Policy as described Section 8.4.7.  Conditions include:

   +===================+==================================+===========+
   | Name              | CDDL Structure                   | Reference |
   +===================+==================================+===========+
   | Vendor Identifier | suit-condition-vendor-identifier | Section   |
   |                   |                                  | 8.4.9.1   |
   +-------------------+----------------------------------+-----------+
   | Class Identifier  | suit-condition-class-identifier  | Section   |
   |                   |                                  | 8.4.9.1   |
   +-------------------+----------------------------------+-----------+
   | Device Identifier | suit-condition-device-identifier | Section   |
   |                   |                                  | 8.4.9.1   |
   +-------------------+----------------------------------+-----------+
   | Image Match       | suit-condition-image-match       | Section   |
   |                   |                                  | 8.4.9.2   |
   +-------------------+----------------------------------+-----------+
   | Component Slot    | suit-condition-component-slot    | Section   |
   |                   |                                  | 8.4.9.3   |
   +-------------------+----------------------------------+-----------+
   | Abort             | suit-condition-abort             | Section   |
   |                   |                                  | 8.4.9.4   |
   +-------------------+----------------------------------+-----------+
   | Custom Condition  | suit-condition-custom            | Section   |
   |                   |                                  | 8.4.9.5   |
   +-------------------+----------------------------------+-----------+

                                 Table 6

   The abstract description of these conditions is defined in
   Section 6.4.

   Conditions compare parameters against properties of the system.
   These properties may be asserted in many different ways, including:
   calculation on-demand, volatile definition in memory, static
   definition within the manifest processor, storage in known location
   within an image, storage within a key storage system, storage in One-
   Time-Programmable memory, inclusion in mask ROM, or inclusion as a
   register in hardware.  Some of these assertion methods are global in
   scope, such as a hardware register, some are scoped to an individual
   component, such as storage at a known location in an image, and some
   assertion methods can be either global or component-scope, based on
   implementation.

   Each condition MUST report a result code on completion.  If a
   condition reports failure, then the current sequence of commands MUST
   terminate.  A subsequent command or command sequence MAY continue
   executing if suit-parameter-soft-failure (Section 8.4.8.14) is set.
   If a condition requires additional information, this MUST be
   specified in one or more parameters before the condition is executed.

   If a Recipient attempts to process a condition that expects
   additional information and that information has not been set, it MUST
   report a failure.  If a Recipient encounters an unknown condition, it
   MUST report a failure.

   Condition labels in the positive number range are reserved for IANA
   registration while those in the negative range are custom conditions
   reserved for proprietary definition by the author of a manifest
   processor.  See Section 11 for more details.

8.4.9.1.  suit-condition-vendor-identifier, suit-condition-class-
          identifier, and suit-condition-device-identifier

   There are three identifier-based conditions: suit-condition-vendor-
   identifier, suit-condition-class-identifier, and suit-condition-
   device-identifier.  Each of these conditions match a RFC 4122
   [RFC4122] UUID that MUST have already been set as a parameter.  The
   installing Recipient MUST match the specified UUID in order to
   consider the manifest valid.  These identifiers are scoped by
   component in the manifest.  Each component MAY match more than one
   identifier.  Care is needed to ensure that manifests correctly
   identify their targets using these conditions.  Using only a generic
   class ID for a device-specific firmware could result in matching
   devices that are not compatible.

   The Recipient uses the ID parameter that has already been set using
   the Set Parameters directive.  If no ID has been set, this condition
   fails. suit-condition-class-identifier and suit-condition-vendor-
   identifier are REQUIRED to implement. suit-condition-device-
   identifier is OPTIONAL to implement.

   Each identifier condition compares the corresponding identifier
   parameter to a parameter asserted to the Manifest Processor by the
   Recipient.  Identifiers MUST be known to the Manifest Processor in
   order to evaluate compatibility.

8.4.9.2.  suit-condition-image-match

   Verify that the current component matches the suit-parameter-image-
   digest (Section 8.4.8.6) for the current component.  The digest is
   verified against the digest specified in the Component's parameters
   list.  If no digest is specified, the condition fails. suit-
   condition-image-match is REQUIRED to implement.

8.4.9.3.  suit-condition-component-slot

   Verify that the slot index of the current component matches the slot
   index set in suit-parameter-component-slot (Section 8.4.8.8).  This
   condition allows a manifest to select between several images to match
   a target slot.

8.4.9.4.  suit-condition-abort

   Unconditionally fail.  This operation is typically used in
   conjunction with suit-directive-try-each (Section 8.4.10.2).

8.4.9.5.  suit-condition-custom

   suit-condition-custom describes any proprietary, application specific
   condition.  This is encoded as a negative integer, chosen by the
   firmware developer.  If additional information must be provided to
   the condition, it should be encoded in a custom parameter (a nint) as
   described in Section 8.4.8.  SUIT_Condition_Custom is OPTIONAL to
   implement.

8.4.10.  SUIT_Directive

   Directives are used to define the behavior of the recipient.
   Directives include:

    +===============+====================================+===========+
    | Name          | CDDL Structure                     | Reference |
    +===============+====================================+===========+
    | Set Component | suit-directive-set-component-index | Section   |
    | Index         |                                    | 8.4.10.1  |
    +---------------+------------------------------------+-----------+
    | Try Each      | suit-directive-try-each            | Section   |
    |               |                                    | 8.4.10.2  |
    +---------------+------------------------------------+-----------+
    | Override      | suit-directive-override-parameters | Section   |
    | Parameters    |                                    | 8.4.10.3  |
    +---------------+------------------------------------+-----------+
    | Fetch         | suit-directive-fetch               | Section   |
    |               |                                    | 8.4.10.4  |
    +---------------+------------------------------------+-----------+
    | Copy          | suit-directive-copy                | Section   |
    |               |                                    | 8.4.10.5  |
    +---------------+------------------------------------+-----------+
    | Run           | suit-directive-run                 | Section   |
    |               |                                    | 8.4.10.6  |
    +---------------+------------------------------------+-----------+
    | Run Sequence  | suit-directive-run-sequence        | Section   |
    |               |                                    | 8.4.10.7  |
    +---------------+------------------------------------+-----------+
    | Swap          | suit-directive-swap                | Section   |
    |               |                                    | 8.4.10.8  |
    +---------------+------------------------------------+-----------+

                                 Table 7

   The abstract description of these commands is defined in Section 6.4.

   When a Recipient executes a Directive, it MUST report a result code.
   If the Directive reports failure, then the current Command Sequence
   MUST be terminated.

8.4.10.1.  suit-directive-set-component-index

   Set Component Index defines the component to which successive
   directives and conditions will apply.  The supplied argument MUST be
   one of three types:

   1.  An unsigned integer (REQUIRED to implement in parser)

   2.  A boolean (REQUIRED to implement in parser ONLY IF 2 or more
       components supported)

   3.  An array of unsigned integers (REQUIRED to implement in parser
       ONLY IF 3 or more components supported)

   If the following commands apply to ONE component, an unsigned integer
   index into the component list is used.  If the following commands
   apply to ALL components, then the boolean value "True" is used
   instead of an index.  If the following commands apply to more than
   one, but not all components, then an array of unsigned integer
   indices into the component list is used.  See Section 6.5 for more
   details.

   If component index is set to True when a command is invoked, then the
   command applies to all components, in the order they appear in suit-
   common-components.  When the Manifest Processor invokes a command
   while the component index is set to True, it must execute the command
   once for each possible component index, ensuring that the command
   receives the parameters corresponding to that component index.

8.4.10.2.  suit-directive-try-each

   This command runs several SUIT_Command_Sequence instances, one after
   another, in a strict order.  Use this command to implement a "try/
   catch-try/catch" sequence.  Manifest processors MAY implement this
   command.

   suit-parameter-soft-failure (Section 8.4.8.14) is initialized to True
   at the beginning of each sequence.  If one sequence aborts due to a
   condition failure, the next is started.  If no sequence completes
   without condition failure, then suit-directive-try-each returns an
   error.  If a particular application calls for all sequences to fail
   and still continue, then an empty sequence (nil) can be added to the
   Try Each Argument.

   The argument to suit-directive-try-each is a list of
   SUIT_Command_Sequence. suit-directive-try-each does not specify a
   reporting policy.

8.4.10.3.  suit-directive-override-parameters

   suit-directive-override-parameters replaces any listed parameters
   that are already set with the values that are provided in its
   argument.  This allows a manifest to prevent replacement of critical
   parameters.

   Available parameters are defined in Section 8.4.8.

   suit-directive-override-parameters does not specify a reporting
   policy.

8.4.10.4.  suit-directive-fetch

   suit-directive-fetch instructs the manifest processor to obtain one
   or more manifests or payloads, as specified by the manifest index and
   component index, respectively.

   suit-directive-fetch can target one or more payloads. suit-directive-
   fetch retrieves each component listed in component-index.  If
   component-index is True, instead of an integer, then all current
   manifest components are fetched.  If component-index is an array,
   then all listed components are fetched.

   suit-directive-fetch typically takes no arguments unless one is
   needed to modify fetch behavior.  If an argument is needed, it must
   be wrapped in a bstr and set in suit-parameter-fetch-arguments.

   suit-directive-fetch reads the URI parameter to find the source of
   the fetch it performs.

8.4.10.5.  suit-directive-copy

   suit-directive-copy instructs the manifest processor to obtain one or
   more payloads, as specified by the component index.  As described in
   Section 6.5 component index may be a single integer, a list of
   integers, or True. suit-directive-copy retrieves each component
   specified by the current component-index, respectively.

   suit-directive-copy reads its source from suit-parameter-source-
   component (Section 8.4.8.10).

   If either the source component parameter or the source component
   itself is absent, this command fails.

8.4.10.6.  suit-directive-run

   suit-directive-run directs the manifest processor to transfer
   execution to the current Component Index.  When this is invoked, the
   manifest processor MAY be unloaded and execution continues in the
   Component Index.  Arguments are provided to suit-directive-run
   through suit-parameter-run-arguments (Section 8.4.8.11) and are
   forwarded to the executable code located in Component Index in an
   application-specific way.  For example, this could form the Linux
   Kernel Command Line if booting a Linux device.

   If the executable code at Component Index is constructed in such a
   way that it does not unload the manifest processor, then the manifest
   processor may resume execution after the executable completes.  This
   allows the manifest processor to invoke suitable helpers and to
   verify them with image conditions.

8.4.10.7.  suit-directive-run-sequence

   To enable conditional commands, and to allow several strictly ordered
   sequences to be executed out-of-order, suit-directive-run-sequence
   allows the manifest processor to execute its argument as a
   SUIT_Command_Sequence.  The argument must be wrapped in a bstr.

   When a sequence is executed, any failure of a condition causes
   immediate termination of the sequence.

   When suit-directive-run-sequence completes, it forwards the last
   status code that occurred in the sequence.  If the Soft Failure
   parameter is true, then suit-directive-run-sequence only fails when a
   directive in the argument sequence fails.

   suit-parameter-soft-failure (Section 8.4.8.14) defaults to False when
   suit-directive-run-sequence begins.  Its value is discarded when
   suit-directive-run-sequence terminates.

8.4.10.8.  suit-directive-swap

   suit-directive-swap instructs the manifest processor to move the
   source to the destination and the destination to the source
   simultaneously.  Swap has nearly identical semantics to suit-
   directive-copy except that suit-directive-swap replaces the source
   with the current contents of the destination in an application-
   defined way.  As with suit-directive-copy, if the source component is
   missing, this command fails.

   If SUIT_Parameter_Compression_Info or SUIT_Parameter_Encryption_Info
   are present, they MUST be handled in a symmetric way, so that the
   source is decompressed into the destination and the destination is
   compressed into the source.  The source is decrypted into the
   destination and the destination is encrypted into the source. suit-
   directive-swap is OPTIONAL to implement.

8.4.11.  Integrity Check Values

   When the Text section or any Command Sequence of the Update Procedure
   is made severable, it is moved to the Envelope and replaced with a
   SUIT_Digest.  The SUIT_Digest is computed over the entire bstr
   enclosing the Manifest element that has been moved to the Envelope.
   Each element that is made severable from the Manifest is placed in
   the Envelope.  The keys for the envelope elements have the same
   values as the keys for the manifest elements.

   Each Integrity Check Value covers the corresponding Envelope Element
   as described in Section 8.5.

8.5.  Severable Elements

   Because the manifest can be used by different actors at different
   times, some parts of the manifest can be removed or "Severed" without
   affecting later stages of the lifecycle.  Severing of information is
   achieved by separating that information from the signed container so
   that removing it does not affect the signature.  This means that
   ensuring integrity of severable parts of the manifest is a
   requirement for the signed portion of the manifest.  Severing some
   parts makes it possible to discard parts of the manifest that are no
   longer necessary.  This is important because it allows the storage
   used by the manifest to be greatly reduced.  For example, no text
   size limits are needed if text is removed from the manifest prior to
   delivery to a constrained device.

   Elements are made severable by removing them from the manifest,
   encoding them in a bstr, and placing a SUIT_Digest of the bstr in the
   manifest so that they can still be authenticated.  The SUIT_Digest
   typically consumes 4 bytes more than the size of the raw digest,
   therefore elements smaller than (Digest Bits)/8 + 4 SHOULD NOT be
   severable.  Elements larger than (Digest Bits)/8 + 4 MAY be
   severable, while elements that are much larger than (Digest Bits)/8 +
   4 SHOULD be severable.

   Because of this, all command sequences in the manifest are encoded in
   a bstr so that there is a single code path needed for all command
   sequences.

9.  Access Control Lists

   To manage permissions in the manifest, there are three models that
   can be used.

   First, the simplest model requires that all manifests are
   authenticated by a single trusted key.  This mode has the advantage
   that only a root manifest needs to be authenticated, since all of its
   dependencies have digests included in the root manifest.

   This simplest model can be extended by adding key delegation without
   much increase in complexity.

   A second model requires an ACL to be presented to the Recipient,
   authenticated by a trusted party or stored on the Recipient.  This
   ACL grants access rights for specific component IDs or Component
   Identifier prefixes to the listed identities or identity groups.  Any
   identity can verify an image digest, but fetching into or fetching
   from a Component Identifier requires approval from the ACL.

   A third model allows a Recipient to provide even more fine-grained
   controls: The ACL lists the Component Identifier or Component
   Identifier prefix that an identity can use, and also lists the
   commands and parameters that the identity can use in combination with
   that Component Identifier.

10.  SUIT Digest Container

   The SUIT digest is a CBOR List containing two elements: an algorithm
   identifier and a bstr containing the bytes of the digest.  Some forms
   of digest may require additional parameters.  These can be added
   following the digest.

   The values of the algorithm identifier are defined by
   [I-D.ietf-cose-hash-algs].  The following algorithms MUST be
   implemented by all Manifest Processors:

   *  SHA-256 (-16)

   The following algorithms MAY be implemented in a Manifest Processor:

   *  SHAKE128 (-18)

   *  SHA-384 (-43)

   *  SHA-512 (-44)

   *  SHAKE256 (-45)

11.  IANA Considerations

   IANA is requested to:

   *  allocate CBOR tag 107 in the CBOR Tags registry for the SUIT
      Envelope.

   *  allocate CBOR tag 1070 in the CBOR Tags registry for the SUIT
      Manifest.

   *  allocate media type application/suit-envelope in the Media Types
      registry.

   *  setup several registries as described below.

   IANA is requested to setup a registry for SUIT manifests.  Several
   registries defined in the subsections below need to be created.

   For each registry, values 0-23 are Standards Action, 24-255 are IETF
   Review, 256-65535 are Expert Review, and 65536 or greater are First
   Come First Served.

   Negative values -23 to 0 are Experimental Use, -24 and lower are
   Private Use.

11.1.  SUIT Commands

            +=======+=====================+==================+
            | Label | Name                | Reference        |
            +=======+=====================+==================+
            | 1     | Vendor Identifier   | Section 8.4.9.1  |
            +-------+---------------------+------------------+
            | 2     | Class Identifier    | Section 8.4.9.1  |
            +-------+---------------------+------------------+
            | 3     | Image Match         | Section 8.4.9.2  |
            +-------+---------------------+------------------+
            | 4     | Reserved            |                  |
            +-------+---------------------+------------------+
            | 5     | Component Slot      | Section 8.4.9.3  |
            +-------+---------------------+------------------+
            | 12    | Set Component Index | Section 8.4.10.1 |
            +-------+---------------------+------------------+
            | 13    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 14    | Abort               |                  |
            +-------+---------------------+------------------+
            | 15    | Try Each            | Section 8.4.10.2 |
            +-------+---------------------+------------------+
            | 16    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 17    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 18    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 19    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 20    | Override Parameters | Section 8.4.10.3 |
            +-------+---------------------+------------------+
            | 21    | Fetch               | Section 8.4.10.4 |
            +-------+---------------------+------------------+
            | 22    | Copy                | Section 8.4.10.5 |
            +-------+---------------------+------------------+
            | 23    | Run                 | Section 8.4.10.6 |
            +-------+---------------------+------------------+
            | 24    | Device Identifier   | Section 8.4.9.1  |
            +-------+---------------------+------------------+
            | 25    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 26    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 27    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 28    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 29    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 30    | Reserved            |                  |
            +-------+---------------------+------------------+
            | 31    | Swap                | Section 8.4.10.8 |
            +-------+---------------------+------------------+
            | 32    | Run Sequence        | Section 8.4.10.7 |
            +-------+---------------------+------------------+
            | 33    | Reserved            |                  |
            +-------+---------------------+------------------+
            | nint  | Custom Condition    | Section 8.4.9.5  |
            +-------+---------------------+------------------+

                                 Table 8

11.2.  SUIT Parameters

              +=======+==================+==================+
              | Label | Name             | Reference        |
              +=======+==================+==================+
              | 1     | Vendor ID        | Section 8.4.8.3  |
              +-------+------------------+------------------+
              | 2     | Class ID         | Section 8.4.8.4  |
              +-------+------------------+------------------+
              | 3     | Image Digest     | Section 8.4.8.6  |
              +-------+------------------+------------------+
              | 4     | Reserved         |                  |
              +-------+------------------+------------------+
              | 5     | Component Slot   | Section 8.4.8.8  |
              +-------+------------------+------------------+
              | 12    | Strict Order     | Section 8.4.8.13 |
              +-------+------------------+------------------+
              | 13    | Soft Failure     | Section 8.4.8.14 |
              +-------+------------------+------------------+
              | 14    | Image Size       | Section 8.4.8.7  |
              +-------+------------------+------------------+
              | 18    | Reserved         |                  |
              +-------+------------------+------------------+
              | 19    | Reserved         |                  |
              +-------+------------------+------------------+
              | 20    | Reserved         |                  |
              +-------+------------------+------------------+
              | 21    | URI              | Section 8.4.8.9  |
              +-------+------------------+------------------+
              | 22    | Source Component | Section 8.4.8.10 |
              +-------+------------------+------------------+
              | 23    | Run Args         | Section 8.4.8.11 |
              +-------+------------------+------------------+
              | 24    | Device ID        | Section 8.4.8.5  |
              +-------+------------------+------------------+
              | 26    | Reserved         |                  |
              +-------+------------------+------------------+
              | 27    | Reserved         |                  |
              +-------+------------------+------------------+
              | 28    | Reserved         |                  |
              +-------+------------------+------------------+
              | 29    | Reserved         |                  |
              +-------+------------------+------------------+
              | 30    | Reserved         |                  |
              +-------+------------------+------------------+
              | nint  | Custom           | Section 8.4.8.15 |
              +-------+------------------+------------------+

                                  Table 9

11.3.  SUIT Text Values

             +=======+======================+===============+
             | Label | Name                 | Reference     |
             +=======+======================+===============+
             | 1     | Manifest Description | Section 8.4.4 |
             +-------+----------------------+---------------+
             | 2     | Update Description   | Section 8.4.4 |
             +-------+----------------------+---------------+
             | 3     | Manifest JSON Source | Section 8.4.4 |
             +-------+----------------------+---------------+
             | 4     | Manifest YAML Source | Section 8.4.4 |
             +-------+----------------------+---------------+
             | nint  | Custom               | Section 8.4.4 |
             +-------+----------------------+---------------+

                                 Table 10

11.4.   SUIT Component Text Values

          +=======+============================+===============+
          | Label | Name                       | Reference     |
          +=======+============================+===============+
          | 1     | Vendor Name                | Section 8.4.4 |
          +-------+----------------------------+---------------+
          | 2     | Model Name                 | Section 8.4.4 |
          +-------+----------------------------+---------------+
          | 3     | Vendor Domain              | Section 8.4.4 |
          +-------+----------------------------+---------------+
          | 4     | Model Info                 | Section 8.4.4 |
          +-------+----------------------------+---------------+
          | 5     | Component Description      | Section 8.4.4 |
          +-------+----------------------------+---------------+
          | 6     | Component Version          | Section 8.4.4 |
          +-------+----------------------------+---------------+
          | 7     | Component Version Required | Section 8.4.4 |
          +-------+----------------------------+---------------+
          | nint  | Custom                     | Section 8.4.4 |
          +-------+----------------------------+---------------+

                                 Table 11

12.  Security Considerations

   This document is about a manifest format protecting and describing
   how to retrieve, install, and invoke firmware images and as such it
   is part of a larger solution for delivering firmware updates to IoT
   devices.  A detailed security treatment can be found in the
   architecture [RFC9019] and in the information model
   [I-D.ietf-suit-information-model] documents.

13.  Acknowledgements

   We would like to thank the following persons for their support in
   designing this mechanism:

   *  Milosch Meriac
   *  Geraint Luff

   *  Dan Ros

   *  John-Paul Stanford

   *  Hugo Vincent

   *  Carsten Bormann

   *  Oeyvind Roenningstad

   *  Frank Audun Kvamtroe

   *  Krzysztof Chru&#347;ci&#324;ski

   *  Andrzej Puzdrowski

   *  Michael Richardson

   *  David Brown

   *  Emmanuel Baccelli

14.  References

14.1.  Normative References

   [I-D.ietf-suit-information-model]
              Moran, B., Tschofenig, H., and H. Birkholz, "A Manifest
              Information Model for Firmware Updates in IoT Devices",
              Work in Progress, Internet-Draft, draft-ietf-suit-
              information-model-13, 8 July 2021,
              <https://www.ietf.org/archive/id/draft-ietf-suit-
              information-model-13.txt>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC4122]  Leach, P., Mealling, M., and R. Salz, "A Universally
              Unique IDentifier (UUID) URN Namespace", RFC 4122,
              DOI 10.17487/RFC4122, July 2005,
              <https://www.rfc-editor.org/info/rfc4122>.

   [RFC8152]  Schaad, J., "CBOR Object Signing and Encryption (COSE)",
              RFC 8152, DOI 10.17487/RFC8152, July 2017,
              <https://www.rfc-editor.org/info/rfc8152>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC9019]  Moran, B., Tschofenig, H., Brown, D., and M. Meriac, "A
              Firmware Update Architecture for Internet of Things",
              RFC 9019, DOI 10.17487/RFC9019, April 2021,
              <https://www.rfc-editor.org/info/rfc9019>.

14.2.  Informative References

   [I-D.ietf-cbor-tags-oid]
              Bormann, C., "Concise Binary Object Representation (CBOR)
              Tags for Object Identifiers", Work in Progress, Internet-
              Draft, draft-ietf-cbor-tags-oid-08, 21 May 2021,
              <https://www.ietf.org/archive/id/draft-ietf-cbor-tags-oid-
              08.txt>.

   [I-D.ietf-cose-hash-algs]
              Schaad, J., "CBOR Object Signing and Encryption (COSE):
              Hash Algorithms", Work in Progress, Internet-Draft, draft-
              ietf-cose-hash-algs-09, 14 September 2020,
              <https://www.ietf.org/archive/id/draft-ietf-cose-hash-
              algs-09.txt>.

   [I-D.ietf-suit-firmware-encryption]
              Tschofenig, H., Housley, R., and B. Moran, "Firmware
              Encryption with SUIT Manifests", Work in Progress,
              Internet-Draft, draft-ietf-suit-firmware-encryption-02, 25
              October 2021, <https://www.ietf.org/archive/id/draft-ietf-
              suit-firmware-encryption-02.txt>.

   [I-D.ietf-teep-architecture]
              Pei, M., Tschofenig, H., Thaler, D., and D. Wheeler,
              "Trusted Execution Environment Provisioning (TEEP)
              Architecture", Work in Progress, Internet-Draft, draft-
              ietf-teep-architecture-15, 12 July 2021,
              <https://www.ietf.org/archive/id/draft-ietf-teep-
              architecture-15.txt>.

   [RFC7228]  Bormann, C., Ersue, M., and A. Keranen, "Terminology for
              Constrained-Node Networks", RFC 7228,
              DOI 10.17487/RFC7228, May 2014,
              <https://www.rfc-editor.org/info/rfc7228>.

   [YAML]     "YAML Ain't Markup Language", 2020, <https://yaml.org/>.

Appendix A.  A.  Full CDDL

   In order to create a valid SUIT Manifest document the structure of
   the corresponding CBOR message MUST adhere to the following CDDL data
   definition.

   To be valid, the following CDDL MUST have the COSE CDDL appended to
   it.  The COSE CDDL can be obtained by following the directions in
   [RFC8152], section 1.4.

   SUIT_Envelope_Tagged = #6.107(SUIT_Envelope)
   SUIT_Envelope = {
     ? suit-delegation => bstr .cbor SUIT_Delegation,
     suit-authentication-wrapper => bstr .cbor SUIT_Authentication,
     suit-manifest  => bstr .cbor SUIT_Manifest,
     SUIT_Severable_Manifest_Members,
     * SUIT_Integrated_Payload,
     * $$SUIT_Envelope_Extensions,
     * (int => bstr)
   }

   SUIT_Authentication = [
       bstr .cbor SUIT_Digest,
       * bstr .cbor SUIT_Authentication_Block
   ]

   SUIT_Digest = [
     suit-digest-algorithm-id : suit-cose-hash-algs,
     suit-digest-bytes : bstr,
     * $$SUIT_Digest-extensions
   ]

   SUIT_Authentication_Block /= COSE_Mac_Tagged
   SUIT_Authentication_Block /= COSE_Sign_Tagged
   SUIT_Authentication_Block /= COSE_Mac0_Tagged
   SUIT_Authentication_Block /= COSE_Sign1_Tagged

   SUIT_Severable_Manifest_Members = (
     ? suit-payload-fetch => bstr .cbor SUIT_Command_Sequence,
     ? suit-install => bstr .cbor SUIT_Command_Sequence,
     ? suit-text => bstr .cbor SUIT_Text_Map,
     ? suit-coswid => bstr .cbor concise-software-identity,
     * $$SUIT_severable-members-extensions,
   )

   SUIT_Integrated_Payload = (suit-integrated-payload-key => bstr)
   suit-integrated-payload-key = tstr

   SUIT_Manifest_Tagged = #6.1070(SUIT_Manifest)

   SUIT_Manifest = {
       suit-manifest-version         => 1,
       suit-manifest-sequence-number => uint,
       suit-common                   => bstr .cbor SUIT_Common,
       ? suit-reference-uri          => tstr,
       SUIT_Severable_Members_Choice,
       SUIT_Unseverable_Members,
       * $$SUIT_Manifest_Extensions,
   }

   SUIT_Unseverable_Members = (
     ? suit-validate => bstr .cbor SUIT_Command_Sequence,
     ? suit-load => bstr .cbor SUIT_Command_Sequence,
     ? suit-run => bstr .cbor SUIT_Command_Sequence,
     * $$unseverable-manifest-member-extensions,
   )

   SUIT_Severable_Members_Choice = (
     ? suit-payload-fetch => \
       bstr .cbor SUIT_Command_Sequence / SUIT_Digest,
     ? suit-install => bstr .cbor SUIT_Command_Sequence / SUIT_Digest,
     ? suit-text => bstr .cbor SUIT_Command_Sequence / SUIT_Digest,
     * $$severable-manifest-members-choice-extensions
   )

   SUIT_Common = {
       ? suit-components             => SUIT_Components,
       ? suit-common-sequence        => bstr .cbor SUIT_Common_Sequence,
       * $$SUIT_Common-extensions,
   }

   SUIT_Components           = [ + SUIT_Component_Identifier ]

   SUIT_Dependency = {
       suit-dependency-digest => SUIT_Digest,
       ? suit-dependency-prefix => SUIT_Component_Identifier,
       * $$SUIT_Dependency-extensions,
   }

   ;REQUIRED to implement:

   suit-cose-hash-algs /= cose-alg-sha-256

   ;OPTIONAL to implement:
   suit-cose-hash-algs /= cose-alg-shake128
   suit-cose-hash-algs /= cose-alg-sha-384
   suit-cose-hash-algs /= cose-alg-sha-512
   suit-cose-hash-algs /= cose-alg-shake256

   SUIT_Component_Identifier =  [* bstr]

   SUIT_Common_Sequence = [
       + ( SUIT_Condition // SUIT_Common_Commands )
   ]

   SUIT_Common_Commands //= (suit-directive-set-component-index,  IndexArg)
   SUIT_Common_Commands //= (suit-directive-run-sequence,
       bstr .cbor SUIT_Command_Sequence)
   SUIT_Common_Commands //= (suit-directive-try-each,
       SUIT_Directive_Try_Each_Argument)
   SUIT_Common_Commands //= (suit-directive-override-parameters,
       {+ SUIT_Parameters})

   IndexArg /= uint
   IndexArg /= bool
   IndexArg /= [+uint]

   SUIT_Command_Sequence = [ + (
       SUIT_Condition // SUIT_Directive // SUIT_Command_Custom
   ) ]

   SUIT_Command_Custom = (suit-command-custom, bstr/tstr/int/nil)
   SUIT_Condition //= (suit-condition-vendor-identifier, SUIT_Rep_Policy)
   SUIT_Condition //= (suit-condition-class-identifier,  SUIT_Rep_Policy)
   SUIT_Condition //= (suit-condition-device-identifier, SUIT_Rep_Policy)
   SUIT_Condition //= (suit-condition-image-match,       SUIT_Rep_Policy)
   SUIT_Condition //= (suit-condition-component-slot,    SUIT_Rep_Policy)
   SUIT_Condition //= (suit-condition-abort,             SUIT_Rep_Policy)

   SUIT_Directive //= (suit-directive-set-component-index,  IndexArg)
   SUIT_Directive //= (suit-directive-run-sequence,
       bstr .cbor SUIT_Command_Sequence)
   SUIT_Directive //= (suit-directive-try-each,
       SUIT_Directive_Try_Each_Argument)
   SUIT_Directive //= (suit-directive-process-dependency, SUIT_Rep_Policy)
   SUIT_Directive //= (suit-directive-override-parameters,
       {+ SUIT_Parameters})
   SUIT_Directive //= (suit-directive-fetch,             SUIT_Rep_Policy)
   SUIT_Directive //= (suit-directive-copy,              SUIT_Rep_Policy)
   SUIT_Directive //= (suit-directive-swap,              SUIT_Rep_Policy)
   SUIT_Directive //= (suit-directive-run,               SUIT_Rep_Policy)

   SUIT_Directive_Try_Each_Argument = [
       2* bstr .cbor SUIT_Command_Sequence,
       ?nil
   ]

   SUIT_Rep_Policy = uint .bits suit-reporting-bits

   suit-reporting-bits = &(
       suit-send-record-success : 0,
       suit-send-record-failure : 1,
       suit-send-sysinfo-success : 2,
       suit-send-sysinfo-failure : 3
   )

   SUIT_Parameters //= (suit-parameter-vendor-identifier =>
       (RFC4122_UUID / cbor-pen))
   cbor-pen = #6.112(bstr)

   SUIT_Parameters //= (suit-parameter-class-identifier => RFC4122_UUID)
   SUIT_Parameters //= (suit-parameter-image-digest
       => bstr .cbor SUIT_Digest)
   SUIT_Parameters //= (suit-parameter-image-size => uint)
   SUIT_Parameters //= (suit-parameter-component-slot => uint)

   SUIT_Parameters //= (suit-parameter-uri => tstr)
   SUIT_Parameters //= (suit-parameter-source-component => uint)
   SUIT_Parameters //= (suit-parameter-run-args => bstr)

   SUIT_Parameters //= (suit-parameter-device-identifier => RFC4122_UUID)

   SUIT_Parameters //= (suit-parameter-custom => int/bool/tstr/bstr)

   SUIT_Parameters //= (suit-parameter-strict-order => bool)
   SUIT_Parameters //= (suit-parameter-soft-failure => bool)

   RFC4122_UUID = bstr .size 16

   SUIT_Text_Map = {
       SUIT_Text_Keys,
       * SUIT_Component_Identifier => {
           SUIT_Text_Component_Keys
       }
   }

   SUIT_Text_Component_Keys = (
       ? suit-text-vendor-name           => tstr,
       ? suit-text-model-name            => tstr,
       ? suit-text-vendor-domain         => tstr,
       ? suit-text-model-info            => tstr,
       ? suit-text-component-description => tstr,
       ? suit-text-component-version     => tstr,
       * $$suit-text-component-key-extensions
   )

   SUIT_Text_Keys = (
       ? suit-text-manifest-description => tstr,
       ? suit-text-update-description   => tstr,
       ? suit-text-manifest-json-source => tstr,
       ? suit-text-manifest-yaml-source => tstr,
       * $$suit-text-key-extensions
   )

   suit-authentication-wrapper = 2
   suit-manifest = 3

   ;REQUIRED to implement:
   cose-alg-sha-256 = -16

   ;OPTIONAL to implement:
   cose-alg-shake128 = -18
   cose-alg-sha-384 = -43
   cose-alg-sha-512 = -44
   cose-alg-shake256 = -45

   suit-manifest-version = 1
   suit-manifest-sequence-number = 2
   suit-common = 3
   suit-reference-uri = 4
   suit-payload-fetch = 8
   suit-install = 9
   suit-validate = 10
   suit-load = 11
   suit-run = 12
   suit-text = 13

   suit-components = 2
   suit-common-sequence = 4

   suit-command-custom = nint

   suit-condition-vendor-identifier = 1
   suit-condition-class-identifier  = 2
   suit-condition-image-match       = 3
   suit-condition-component-slot    = 5

   suit-condition-abort                    = 14
   suit-condition-device-identifier        = 24

   suit-directive-set-component-index      = 12
   suit-directive-try-each                 = 15
   suit-directive-override-parameters      = 20
   suit-directive-fetch                    = 21
   suit-directive-copy                     = 22
   suit-directive-run                      = 23

   suit-directive-swap                     = 31
   suit-directive-run-sequence             = 32

   suit-parameter-vendor-identifier = 1
   suit-parameter-class-identifier  = 2
   suit-parameter-image-digest      = 3
   suit-parameter-component-slot    = 5

   suit-parameter-strict-order      = 12
   suit-parameter-soft-failure      = 13
   suit-parameter-image-size        = 14

   suit-parameter-uri               = 21
   suit-parameter-source-component  = 22
   suit-parameter-run-args          = 23

   suit-parameter-device-identifier = 24

   suit-parameter-custom = nint

   suit-text-manifest-description  = 1
   suit-text-update-description    = 2
   suit-text-manifest-json-source  = 3
   suit-text-manifest-yaml-source  = 4

   suit-text-vendor-name           = 1
   suit-text-model-name            = 2
   suit-text-vendor-domain         = 3
   suit-text-model-info            = 4
   suit-text-component-description = 5
   suit-text-component-version     = 6

Appendix B.  B.  Examples

   The following examples demonstrate a small subset of the
   functionality of the manifest.  Even a simple manifest processor can
   execute most of these manifests.

   The examples are signed using the following ECDSA secp256r1 key:

   -----BEGIN PRIVATE KEY-----
   MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgApZYjZCUGLM50VBC
   CjYStX+09jGmnyJPrpDLTz/hiXOhRANCAASEloEarguqq9JhVxie7NomvqqL8Rtv
   P+bitWWchdvArTsfKktsCYExwKNtrNHXi9OB3N+wnAUtszmR23M4tKiW
   -----END PRIVATE KEY-----

   The corresponding public key can be used to verify these examples:

   -----BEGIN PUBLIC KEY-----
   MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEhJaBGq4LqqvSYVcYnuzaJr6qi/Eb
   bz/m4rVlnIXbwK07HypLbAmBMcCjbazR14vTgdzfsJwFLbM5kdtzOLSolg==
   -----END PUBLIC KEY-----

   Each example uses SHA256 as the digest function.

   Note that reporting policies are declared for each non-flow-control
   command in these examples.  The reporting policies used in the
   examples are described in the following tables.

                +=============================+==========+
                | Policy                      | Label    |
                +=============================+==========+
                | suit-send-record-on-success | Rec-Pass |
                +-----------------------------+----------+
                | suit-send-record-on-failure | Rec-Fail |
                +-----------------------------+----------+
                | suit-send-sysinfo-success   | Sys-Pass |
                +-----------------------------+----------+
                | suit-send-sysinfo-failure   | Sys-Fail |
                +-----------------------------+----------+

                                 Table 12

     +===================+==========+==========+==========+==========+
     | Command           | Sys-Fail | Sys-Pass | Rec-Fail | Rec-Pass |
     +===================+==========+==========+==========+==========+
     | suit-condition-   | 1        | 1        | 1        | 1        |
     | vendor-identifier |          |          |          |          |
     +-------------------+----------+----------+----------+----------+
     | suit-condition-   | 1        | 1        | 1        | 1        |
     | class-identifier  |          |          |          |          |
     +-------------------+----------+----------+----------+----------+
     | suit-condition-   | 1        | 1        | 1        | 1        |
     | image-match       |          |          |          |          |
     +-------------------+----------+----------+----------+----------+
     | suit-condition-   | 0        | 1        | 0        | 1        |
     | component-slot    |          |          |          |          |
     +-------------------+----------+----------+----------+----------+
     | suit-directive-   | 0        | 0        | 1        | 0        |
     | fetch             |          |          |          |          |
     +-------------------+----------+----------+----------+----------+
     | suit-directive-   | 0        | 0        | 1        | 0        |
     | copy              |          |          |          |          |
     +-------------------+----------+----------+----------+----------+
     | suit-directive-   | 0        | 0        | 1        | 0        |
     | run               |          |          |          |          |
     +-------------------+----------+----------+----------+----------+

                                  Table 13

B.1.  Example 0: Secure Boot

   This example covers the following templates:

   *  Compatibility Check (Section 7.1)

   *  Secure Boot (Section 7.2)

   It also serves as the minimum example.

  107({
          / authentication-wrapper / 2:<<[
              digest: <<[
                  / algorithm-id / -16 / "sha256" /,
                  / digest-bytes /
  h'a6c4590ac53043a98e8c4106e1e31b305516d7cf0a655eddfac6d45c810e036a'
              ]>>,
              signature: <<18([
                      / protected / <<{
                          / alg / 1:-7 / "ES256" /,
                      }>>,
                      / unprotected / {
                      },
                      / payload / F6 / nil /,
                      / signature / h'd11a2dd9610fb62a707335f58407922570
  9f96e8117e7eeed98a2f207d05c8ecfba1755208f6abea977b8a6efe3bc2ca3215e119
  3be201467d052b42db6b7287'
                  ])>>
              ]
          ]>>,
          / manifest / 3:<<{
              / manifest-version / 1:1,
              / manifest-sequence-number / 2:0,
              / common / 3:<<{
                  / components / 2:[
                      [h'00']
                  ],
                  / common-sequence / 4:<<[
                      / directive-override-parameters / 20,{
                          / vendor-id /
  1:h'fa6b4a53d5ad5fdfbe9de663e4d41ffe' / fa6b4a53-d5ad-5fdf-
  be9d-e663e4d41ffe /,
                          / class-id /
  2:h'1492af1425695e48bf429b2d51f2ab45' /
  1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
                          / image-digest / 3:<<[
                              / algorithm-id / -16 / "sha256" /,
                              / digest-bytes /
  h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
                          ]>>,
                          / image-size / 14:34768,
                      } ,
                      / condition-vendor-identifier / 1,15 ,
                      / condition-class-identifier / 2,15
                  ]>>,
              }>>,
              / validate / 10:<<[
                  / condition-image-match / 3,15
              ]>>,
              / run / 12:<<[
                  / directive-run / 23,2
              ]>>,
          }>>,
      })

   Total size of Envelope without COSE authentication object: 161

   Envelope:

   d86ba2025827815824822f5820a6c4590ac53043a98e8c4106e1e31b3055
   16d7cf0a655eddfac6d45c810e036a035871a50101020003585fa2028181
   41000458568614a40150fa6b4a53d5ad5fdfbe9de663e4d41ffe02501492
   af1425695e48bf429b2d51f2ab45035824822f5820001122334455667788
   99aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f02
   0f0a4382030f0c43821702

   Total size of Envelope with COSE authentication object: 237

   Envelope with COSE authentication object:

   d86ba2025873825824822f5820a6c4590ac53043a98e8c4106e1e31b3055
   16d7cf0a655eddfac6d45c810e036a584ad28443a10126a0f65840d11a2d
   d9610fb62a707335f584079225709f96e8117e7eeed98a2f207d05c8ecfb
   a1755208f6abea977b8a6efe3bc2ca3215e1193be201467d052b42db6b72
   87035871a50101020003585fa202818141000458568614a40150fa6b4a53
   d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab45
   035824822f582000112233445566778899aabbccddeeff0123456789abcd
   effedcba98765432100e1987d0010f020f0a4382030f0c43821702

B.2.  Example 1: Simultaneous Download and Installation of Payload

   This example covers the following templates:

   *  Compatibility Check (Section 7.1)

   *  Firmware Download (Section 7.3)

   Simultaneous download and installation of payload.  No secure boot is
   present in this example to demonstrate a download-only manifest.

  107({
          / authentication-wrapper / 2:<<[
              digest: <<[
                  / algorithm-id / -16 / "sha256" /,
                  / digest-bytes /
  h'60c61d6eb7a1aaeddc49ce8157a55cff0821537eeee77a4ded44155b03045132'
              ]>>,
              signature: <<18([
                      / protected / <<{
                          / alg / 1:-7 / "ES256" /,
                      }>>,
                      / unprotected / {
                      },
                      / payload / F6 / nil /,
                      / signature / h'5249dacaf0ffc8326931b09586eb7e3769
  e71a0e6a40ad8153db4980db9b05bd1742ddb46085fa11e62b65a79895c12ac7abe266
  8ccc5afdd74466aed7bca389'
                  ])>>
              ]
          ]>>,
          / manifest / 3:<<{
              / manifest-version / 1:1,
              / manifest-sequence-number / 2:1,
              / common / 3:<<{
                  / components / 2:[
                      [h'00']
                  ],
                  / common-sequence / 4:<<[
                      / directive-override-parameters / 20,{
                          / vendor-id /
  1:h'fa6b4a53d5ad5fdfbe9de663e4d41ffe' / fa6b4a53-d5ad-5fdf-
  be9d-e663e4d41ffe /,
                          / class-id /
  2:h'1492af1425695e48bf429b2d51f2ab45' /
  1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
                          / image-digest / 3:<<[
                              / algorithm-id / -16 / "sha256" /,
                              / digest-bytes /
  h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
                          ]>>,
                          / image-size / 14:34768,
                      } ,
                      / condition-vendor-identifier / 1,15 ,
                      / condition-class-identifier / 2,15
                  ]>>,
              }>>,
              / install / 9:<<[
                  / directive-set-parameters / 19,{
                      / uri / 21:'http://example.com/file.bin',
                  } ,
                  / directive-fetch / 21,2 ,
                  / condition-image-match / 3,15
              ]>>,
              / validate / 10:<<[
                  / condition-image-match / 3,15
              ]>>,
          }>>,
      })

   Total size of Envelope without COSE authentication object: 196

   Envelope:

   d86ba2025827815824822f582060c61d6eb7a1aaeddc49ce8157a55cff08
   21537eeee77a4ded44155b03045132035894a50101020103585fa2028181
   41000458568614a40150fa6b4a53d5ad5fdfbe9de663e4d41ffe02501492
   af1425695e48bf429b2d51f2ab45035824822f5820001122334455667788
   99aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f02
   0f0958258613a115781b687474703a2f2f6578616d706c652e636f6d2f66
   696c652e62696e1502030f0a4382030f

   Total size of Envelope with COSE authentication object: 272

   Envelope with COSE authentication object:

   d86ba2025873825824822f582060c61d6eb7a1aaeddc49ce8157a55cff08
   21537eeee77a4ded44155b03045132584ad28443a10126a0f658405249da
   caf0ffc8326931b09586eb7e3769e71a0e6a40ad8153db4980db9b05bd17
   42ddb46085fa11e62b65a79895c12ac7abe2668ccc5afdd74466aed7bca3
   89035894a50101020103585fa202818141000458568614a40150fa6b4a53
   d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab45
   035824822f582000112233445566778899aabbccddeeff0123456789abcd
   effedcba98765432100e1987d0010f020f0958258613a115781b68747470
   3a2f2f6578616d706c652e636f6d2f66696c652e62696e1502030f0a4382
   030f

B.3.  Example 2: Simultaneous Download, Installation, Secure Boot,
      Severed Fields

   This example covers the following templates:

   *  Compatibility Check (Section 7.1)

   *  Secure Boot (Section 7.2)

   *  Firmware Download (Section 7.3)

   This example also demonstrates severable elements (Section 5.4), and
   text (Section 8.4.4).

  107({
          / authentication-wrapper / 2:<<[
              digest: <<[
                  / algorithm-id / -16 / "sha256" /,
                  / digest-bytes /
  h'e45dcdb2074b951f1c88b866469939c2a83ed433a31fc7dfcb3f63955bd943ec'
              ]>>,
              signature: <<18([
                      / protected / <<{
                          / alg / 1:-7 / "ES256" /,
                      }>>,
                      / unprotected / {
                      },
                      / payload / F6 / nil /,
                      / signature / h'b4fd3a6a18fe1062573488cf24ac96ef9f
  30ac746696e50be96533b356b8156e4332587fe6f4e8743ae525d72005fddd4c1213d5
  5a8061b2ce67b83640f4777c'
                  ])>>
              ]
          ]>>,
          / manifest / 3:<<{
              / manifest-version / 1:1,
              / manifest-sequence-number / 2:2,
              / common / 3:<<{
                  / components / 2:[
                      [h'00']
                  ],
                  / common-sequence / 4:<<[
                      / directive-override-parameters / 20,{
                          / vendor-id /
  1:h'fa6b4a53d5ad5fdfbe9de663e4d41ffe' / fa6b4a53-d5ad-5fdf-
  be9d-e663e4d41ffe /,
                          / class-id /
  2:h'1492af1425695e48bf429b2d51f2ab45' /
  1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
                          / image-digest / 3:<<[
                              / algorithm-id / -16 / "sha256" /,
                              / digest-bytes /
  h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
                          ]>>,
                          / image-size / 14:34768,
                      } ,
                      / condition-vendor-identifier / 1,15 ,
                      / condition-class-identifier / 2,15
                  ]>>,
              }>>,
              / install / 9:[
                  / algorithm-id / -16 / "sha256" /,
                  / digest-bytes /
  h'3ee96dc79641970ae46b929ccf0b72ba9536dd846020dbdc9f949d84ea0e18d2'
              ],
              / validate / 10:<<[
                  / condition-image-match / 3,15
              ]>>,
              / run / 12:<<[
                  / directive-run / 23,2
              ]>>,
              / text / 13:[
                  / algorithm-id / -16 / "sha256" /,
                  / digest-bytes /
  h'2bfc4d0cc6680be7dd9f5ca30aa2bb5d1998145de33d54101b80e2ca49faf918'
              ],
          }>>,
          / install / 9:<<[
              / directive-set-parameters / 19,{
                  / uri /
  21:'http://example.com/very/long/path/to/file/file.bin',
              } ,
              / directive-fetch / 21,2 ,
              / condition-image-match / 3,15
          ]>>,
          / text / 13:<<{
              [h'00']:{
                      / vendor-domain / 3:'arm.com',
                      / component-description / 5:'This component is a
  demonstration. The digest is a sample pattern, not a real one.',
                  }
          }>>,
      })

   Total size of the Envelope without COSE authentication object or
   Severable Elements: 235

   Envelope:

   d86ba2025827815824822f5820e45dcdb2074b951f1c88b866469939c2a8
   3ed433a31fc7dfcb3f63955bd943ec0358bba70101020203585fa2028181
   41000458568614a40150fa6b4a53d5ad5fdfbe9de663e4d41ffe02501492
   af1425695e48bf429b2d51f2ab45035824822f5820001122334455667788
   99aabbccddeeff0123456789abcdeffedcba98765432100e1987d0010f02
   0f09822f58203ee96dc79641970ae46b929ccf0b72ba9536dd846020dbdc
   9f949d84ea0e18d20a4382030f0c438217020d822f58202bfc4d0cc6680b
   e7dd9f5ca30aa2bb5d1998145de33d54101b80e2ca49faf918

   Total size of the Envelope with COSE authentication object but
   without Severable Elements: 311

   Envelope:

   d86ba2025873825824822f5820e45dcdb2074b951f1c88b866469939c2a8
   3ed433a31fc7dfcb3f63955bd943ec584ad28443a10126a0f65840b4fd3a
   6a18fe1062573488cf24ac96ef9f30ac746696e50be96533b356b8156e43
   32587fe6f4e8743ae525d72005fddd4c1213d55a8061b2ce67b83640f477
   7c0358bba70101020203585fa202818141000458568614a40150fa6b4a53
   d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab45
   035824822f582000112233445566778899aabbccddeeff0123456789abcd
   effedcba98765432100e1987d0010f020f09822f58203ee96dc79641970a
   e46b929ccf0b72ba9536dd846020dbdc9f949d84ea0e18d20a4382030f0c
   438217020d822f58202bfc4d0cc6680be7dd9f5ca30aa2bb5d1998145de3
   3d54101b80e2ca49faf918

   Total size of Envelope with COSE authentication object and Severable
   Elements: 894

   Envelope with COSE authentication object:

   d86ba4025873825824822f5820e45dcdb2074b951f1c88b866469939c2a8
   3ed433a31fc7dfcb3f63955bd943ec584ad28443a10126a0f65840b4fd3a
   6a18fe1062573488cf24ac96ef9f30ac746696e50be96533b356b8156e43
   32587fe6f4e8743ae525d72005fddd4c1213d55a8061b2ce67b83640f477
   7c0358bba70101020203585fa202818141000458568614a40150fa6b4a53
   d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab45
   035824822f582000112233445566778899aabbccddeeff0123456789abcd
   effedcba98765432100e1987d0010f020f09822f58203ee96dc79641970a
   e46b929ccf0b72ba9536dd846020dbdc9f949d84ea0e18d20a4382030f0c
   438217020d822f58202bfc4d0cc6680be7dd9f5ca30aa2bb5d1998145de3
   3d54101b80e2ca49faf91809583c8613a1157832687474703a2f2f657861
   6d706c652e636f6d2f766572792f6c6f6e672f706174682f746f2f66696c
   652f66696c652e62696e1502030f0d590204a20179019d2323204578616d
   706c6520323a2053696d756c74616e656f757320446f776e6c6f61642c20
   496e7374616c6c6174696f6e2c2053656375726520426f6f742c20536576
   65726564204669656c64730a0a2020202054686973206578616d706c6520
   636f766572732074686520666f6c6c6f77696e672074656d706c61746573
   3a0a202020200a202020202a20436f6d7061746962696c69747920436865
   636b20287b7b74656d706c6174652d636f6d7061746962696c6974792d63
   6865636b7d7d290a202020202a2053656375726520426f6f7420287b7b74
   656d706c6174652d7365637572652d626f6f747d7d290a202020202a2046
   69726d7761726520446f776e6c6f616420287b7b6669726d776172652d64
   6f776e6c6f61642d74656d706c6174657d7d290a202020200a2020202054
   686973206578616d706c6520616c736f2064656d6f6e7374726174657320
   736576657261626c6520656c656d656e747320287b7b6f76722d73657665
   7261626c657d7d292c20616e64207465787420287b7b6d616e6966657374
   2d6469676573742d746578747d7d292e814100a2036761726d2e636f6d05
   78525468697320636f6d706f6e656e7420697320612064656d6f6e737472
   6174696f6e2e205468652064696765737420697320612073616d706c6520
   7061747465726e2c206e6f742061207265616c206f6e652e

B.4.  Example 3: A/B images

   This example covers the following templates:

   *  Compatibility Check (Section 7.1)

   *  Secure Boot (Section 7.2)

   *  Firmware Download (Section 7.3)

   *  A/B Image Template (Section 7.7)

  107({
          / authentication-wrapper / 2:<<[
              digest: <<[
                  / algorithm-id / -16 / "sha256" /,
                  / digest-bytes /
  h'7c9b3cb72c262608a42f944d59d659ff2b801c78af44def51b8ff51e9f45721b'
              ]>>,
              signature: <<18([
                      / protected / <<{
                          / alg / 1:-7 / "ES256" /,
                      }>>,
                      / unprotected / {
                      },
                      / payload / F6 / nil /,
                      / signature / h'e33d618df0ad21e609529ab1a876afb231
  faff1d6a3189b5360324c2794250b87cf00cf83be50ea17dc721ca85393cd8e839a066
  d5dec0ad87a903ab31ea9afa'
                  ])>>
              ]
          ]>>,
          / manifest / 3:<<{
              / manifest-version / 1:1,
              / manifest-sequence-number / 2:3,
              / common / 3:<<{
                  / components / 2:[
                      [h'00']
                  ],
                  / common-sequence / 4:<<[
                      / directive-override-parameters / 20,{
                          / vendor-id /
  1:h'fa6b4a53d5ad5fdfbe9de663e4d41ffe' / fa6b4a53-d5ad-5fdf-
  be9d-e663e4d41ffe /,
                          / class-id /
  2:h'1492af1425695e48bf429b2d51f2ab45' /
  1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
                      } ,
                      / directive-try-each / 15,[
                          <<[
                              / directive-override-parameters / 20,{
                                  / offset / 5:33792,
                              } ,
                              / condition-component-offset / 5,5 ,
                              / directive-override-parameters / 20,{
                                  / image-digest / 3:<<[
                                      / algorithm-id / -16 / "sha256" /,
                                      / digest-bytes /
  h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
                                  ]>>,
                                  / image-size / 14:34768,
                              }
                          ]>> ,
                          <<[
                              / directive-override-parameters / 20,{
                                  / offset / 5:541696,
                              } ,
                              / condition-component-offset / 5,5 ,
                              / directive-override-parameters / 20,{
                                  / image-digest / 3:<<[
                                      / algorithm-id / -16 / "sha256" /,
                                      / digest-bytes /
  h'0123456789abcdeffedcba987654321000112233445566778899aabbccddeeff'
                                  ]>>,
                                  / image-size / 14:76834,
                              }
                          ]>>
                      ] ,
                      / condition-vendor-identifier / 1,15 ,
                      / condition-class-identifier / 2,15
                  ]>>,
              }>>,
              / install / 9:<<[
                  / directive-try-each / 15,[
                      <<[
                          / directive-set-parameters / 19,{
                              / offset / 5:33792,
                          } ,
                          / condition-component-offset / 5,5 ,
                          / directive-set-parameters / 19,{
                              / uri / 21:'http://example.com/file1.bin',
                          }
                      ]>> ,
                      <<[
                          / directive-set-parameters / 19,{
                              / offset / 5:541696,

                          } ,
                          / condition-component-offset / 5,5 ,
                          / directive-set-parameters / 19,{
                              / uri / 21:'http://example.com/file2.bin',
                          }
                      ]>>
                  ] ,
                  / directive-fetch / 21,2 ,
                  / condition-image-match / 3,15
              ]>>,
              / validate / 10:<<[
                  / condition-image-match / 3,15
              ]>>,
          }>>,
      })

   Total size of Envelope without COSE authentication object: 332

   Envelope:

   d86ba2025827815824822f58207c9b3cb72c262608a42f944d59d659ff2b
   801c78af44def51b8ff51e9f45721b0359011ba5010102030358aaa20281
   8141000458a18814a20150fa6b4a53d5ad5fdfbe9de663e4d41ffe025014
   92af1425695e48bf429b2d51f2ab450f8258368614a105198400050514a2
   035824822f582000112233445566778899aabbccddeeff0123456789abcd
   effedcba98765432100e1987d0583a8614a1051a00084400050514a20358
   24822f58200123456789abcdeffedcba9876543210001122334455667788
   99aabbccddeeff0e1a00012c22010f020f095861860f82582a8613a10519
   8400050513a115781c687474703a2f2f6578616d706c652e636f6d2f6669
   6c65312e62696e582c8613a1051a00084400050513a115781c687474703a
   2f2f6578616d706c652e636f6d2f66696c65322e62696e1502030f0a4382
   030f

   Total size of Envelope with COSE authentication object: 408

   Envelope with COSE authentication object:

   d86ba2025873825824822f58207c9b3cb72c262608a42f944d59d659ff2b
   801c78af44def51b8ff51e9f45721b584ad28443a10126a0f65840e33d61
   8df0ad21e609529ab1a876afb231faff1d6a3189b5360324c2794250b87c
   f00cf83be50ea17dc721ca85393cd8e839a066d5dec0ad87a903ab31ea9a
   fa0359011ba5010102030358aaa202818141000458a18814a20150fa6b4a
   53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf429b2d51f2ab
   450f8258368614a105198400050514a2035824822f582000112233445566
   778899aabbccddeeff0123456789abcdeffedcba98765432100e1987d058
   3a8614a1051a00084400050514a2035824822f58200123456789abcdeffe
   dcba987654321000112233445566778899aabbccddeeff0e1a00012c2201
   0f020f095861860f82582a8613a105198400050513a115781c687474703a
   2f2f6578616d706c652e636f6d2f66696c65312e62696e582c8613a1051a
   00084400050513a115781c687474703a2f2f6578616d706c652e636f6d2f
   66696c65322e62696e1502030f0a4382030f

B.5.  Example 4: Load from External Storage

   This example covers the following templates:

   *  Compatibility Check (Section 7.1)

   *  Secure Boot (Section 7.2)

   *  Firmware Download (Section 7.3)

   *  Install (Section 7.4)

   *  Load (Section 7.6)

  107({
          / authentication-wrapper / 2:<<[
              digest: <<[
                  / algorithm-id / -16 / "sha256" /,
                  / digest-bytes /
  h'15736702a00f510805dcf89d6913a2cfb417ed414faa760f974d6755c68ba70a'
              ]>>,
              signature: <<18([
                      / protected / <<{
                          / alg / 1:-7 / "ES256" /,
                      }>>,
                      / unprotected / {
                      },
                      / payload / F6 / nil /,
                      / signature / h'3ada2532326d512132c388677798c24ffd
  cc979bfae2a26b19c8c8bbf511fd7dd85f1501662c1a9e1976b759c4019bab44ba5434
  efb45d3868aedbca593671f3'
                  ])>>
              ]

          ]>>,
          / manifest / 3:<<{
              / manifest-version / 1:1,
              / manifest-sequence-number / 2:4,
              / common / 3:<<{
                  / components / 2:[
                      [h'00'] ,
                      [h'02'] ,
                      [h'01']
                  ],
                  / common-sequence / 4:<<[
                      / directive-set-component-index / 12,0 ,
                      / directive-override-parameters / 20,{
                          / vendor-id /
  1:h'fa6b4a53d5ad5fdfbe9de663e4d41ffe' / fa6b4a53-d5ad-5fdf-
  be9d-e663e4d41ffe /,
                          / class-id /
  2:h'1492af1425695e48bf429b2d51f2ab45' /
  1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
                          / image-digest / 3:<<[
                              / algorithm-id / -16 / "sha256" /,
                              / digest-bytes /
  h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
                          ]>>,
                          / image-size / 14:34768,
                      } ,
                      / condition-vendor-identifier / 1,15 ,
                      / condition-class-identifier / 2,15
                  ]>>,
              }>>,
              / payload-fetch / 8:<<[
                  / directive-set-component-index / 12,1 ,
                  / directive-set-parameters / 19,{
                      / uri / 21:'http://example.com/file.bin',
                  } ,
                  / directive-fetch / 21,2 ,
                  / condition-image-match / 3,15
              ]>>,
              / install / 9:<<[
                  / directive-set-component-index / 12,0 ,
                  / directive-set-parameters / 19,{
                      / source-component / 22:1 / [h'02'] /,
                  } ,
                  / directive-copy / 22,2 ,
                  / condition-image-match / 3,15
              ]>>,
              / validate / 10:<<[
                  / directive-set-component-index / 12,0 ,
                  / condition-image-match / 3,15
              ]>>,
              / load / 11:<<[
                  / directive-set-component-index / 12,2 ,
                  / directive-set-parameters / 19,{
                      / image-digest / 3:<<[
                          / algorithm-id / -16 / "sha256" /,
                          / digest-bytes /
  h'0123456789abcdeffedcba987654321000112233445566778899aabbccddeeff'
                      ]>>,
                      / image-size / 14:76834,
                      / source-component / 22:0 / [h'00'] /,
                      / compression-info / 19:<<{
                          / compression-algorithm / 1:1 / "gzip" /,
                      }>>,
                  } ,
                  / directive-copy / 22,2 ,
                  / condition-image-match / 3,15
              ]>>,
              / run / 12:<<[
                  / directive-set-component-index / 12,2 ,
                  / directive-run / 23,2
              ]>>,
          }>>,
      })

   Total size of Envelope without COSE authentication object: 292

   Envelope:

   d86ba2025827815824822f582015736702a00f510805dcf89d6913a2cfb4
   17ed414faa760f974d6755c68ba70a0358f4a801010204035867a2028381
   4100814102814101045858880c0014a40150fa6b4a53d5ad5fdfbe9de663
   e4d41ffe02501492af1425695e48bf429b2d51f2ab45035824822f582000
   112233445566778899aabbccddeeff0123456789abcdeffedcba98765432
   100e1987d0010f020f085827880c0113a115781b687474703a2f2f657861
   6d706c652e636f6d2f66696c652e62696e1502030f094b880c0013a11601
   1602030f0a45840c00030f0b583d880c0213a4035824822f582001234567
   89abcdeffedcba987654321000112233445566778899aabbccddeeff0e1a
   00012c221343a1010116001602030f0c45840c021702

   Total size of Envelope with COSE authentication object: 368

   Envelope with COSE authentication object:

   d86ba2025873825824822f582015736702a00f510805dcf89d6913a2cfb4
   17ed414faa760f974d6755c68ba70a584ad28443a10126a0f658403ada25
   32326d512132c388677798c24ffdcc979bfae2a26b19c8c8bbf511fd7dd8
   5f1501662c1a9e1976b759c4019bab44ba5434efb45d3868aedbca593671
   f30358f4a801010204035867a20283814100814102814101045858880c00
   14a40150fa6b4a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48
   bf429b2d51f2ab45035824822f582000112233445566778899aabbccddee
   ff0123456789abcdeffedcba98765432100e1987d0010f020f085827880c
   0113a115781b687474703a2f2f6578616d706c652e636f6d2f66696c652e
   62696e1502030f094b880c0013a116011602030f0a45840c00030f0b583d
   880c0213a4035824822f58200123456789abcdeffedcba98765432100011
   2233445566778899aabbccddeeff0e1a00012c221343a101011600160203
   0f0c45840c021702

B.6.  Example 5: Two Images

   This example covers the following templates:

   *  Compatibility Check (Section 7.1)

   *  Secure Boot (Section 7.2)

   *  Firmware Download (Section 7.3)

   Furthermore, it shows using these templates with two images.

  107({
          / authentication-wrapper / 2:<<[
              digest: <<[
                  / algorithm-id / -16 / "sha256" /,
                  / digest-bytes /
  h'd1e73f16e4126007bc4d804cd33b0209fbab34728e60ee8c00f3387126748dd2'
              ]>>,
              signature: <<18([
                      / protected / <<{
                          / alg / 1:-7 / "ES256" /,
                      }>>,
                      / unprotected / {
                      },
                      / payload / F6 / nil /,
                      / signature / h'b7ae0a46a28f02e25cda6d9a255bbaf863
  30141831fae5a78012d648bc6cee55102e0f1890bdeacc3adaa4fae0560f83a45eecae
  65cabce642f56d84ab97ef8d'
                  ])>>
              ]
          ]>>,
          / manifest / 3:<<{
              / manifest-version / 1:1,
              / manifest-sequence-number / 2:5,
              / common / 3:<<{
                  / components / 2:[
                      [h'00'] ,
                      [h'01']
                  ],
                  / common-sequence / 4:<<[
                      / directive-set-component-index / 12,0 ,
                      / directive-override-parameters / 20,{
                          / vendor-id /
  1:h'fa6b4a53d5ad5fdfbe9de663e4d41ffe' / fa6b4a53-d5ad-5fdf-
  be9d-e663e4d41ffe /,
                          / class-id /
  2:h'1492af1425695e48bf429b2d51f2ab45' /
  1492af14-2569-5e48-bf42-9b2d51f2ab45 /,
                          / image-digest / 3:<<[
                              / algorithm-id / -16 / "sha256" /,
                              / digest-bytes /
  h'00112233445566778899aabbccddeeff0123456789abcdeffedcba9876543210'
                          ]>>,
                          / image-size / 14:34768,
                      } ,
                      / condition-vendor-identifier / 1,15 ,
                      / condition-class-identifier / 2,15 ,
                      / directive-set-component-index / 12,1 ,
                      / directive-override-parameters / 20,{
                          / image-digest / 3:<<[
                              / algorithm-id / -16 / "sha256" /,
                              / digest-bytes /
  h'0123456789abcdeffedcba987654321000112233445566778899aabbccddeeff'
                          ]>>,
                          / image-size / 14:76834,
                      }
                  ]>>,
              }>>,
              / install / 9:<<[
                  / directive-set-component-index / 12,0 ,
                  / directive-set-parameters / 19,{
                      / uri / 21:'http://example.com/file1.bin',
                  } ,
                  / directive-fetch / 21,2 ,
                  / condition-image-match / 3,15 ,
                  / directive-set-component-index / 12,1 ,
                  / directive-set-parameters / 19,{
                      / uri / 21:'http://example.com/file2.bin',
                  } ,
                  / directive-fetch / 21,2 ,
                  / condition-image-match / 3,15

              ]>>,
              / validate / 10:<<[
                  / directive-set-component-index / 12,0 ,
                  / condition-image-match / 3,15 ,
                  / directive-set-component-index / 12,1 ,
                  / condition-image-match / 3,15
              ]>>,
              / run / 12:<<[
                  / directive-set-component-index / 12,0 ,
                  / directive-run / 23,2
              ]>>,
          }>>,
      })

   Total size of Envelope without COSE authentication object: 306

   Envelope:

   d86ba2025827815824822f5820d1e73f16e4126007bc4d804cd33b0209fb
   ab34728e60ee8c00f3387126748dd203590101a601010205035895a20282
   8141008141010458898c0c0014a40150fa6b4a53d5ad5fdfbe9de663e4d4
   1ffe02501492af1425695e48bf429b2d51f2ab45035824822f5820001122
   33445566778899aabbccddeeff0123456789abcdeffedcba98765432100e
   1987d0010f020f0c0114a2035824822f58200123456789abcdeffedcba98
   7654321000112233445566778899aabbccddeeff0e1a00012c2209584f90
   0c0013a115781c687474703a2f2f6578616d706c652e636f6d2f66696c65
   312e62696e1502030f0c0113a115781c687474703a2f2f6578616d706c65
   2e636f6d2f66696c65322e62696e1502030f0a49880c00030f0c01030f0c
   45840c001702

   Total size of Envelope with COSE authentication object: 382

   Envelope with COSE authentication object:

   d86ba2025873825824822f5820d1e73f16e4126007bc4d804cd33b0209fb
   ab34728e60ee8c00f3387126748dd2584ad28443a10126a0f65840b7ae0a
   46a28f02e25cda6d9a255bbaf86330141831fae5a78012d648bc6cee5510
   2e0f1890bdeacc3adaa4fae0560f83a45eecae65cabce642f56d84ab97ef
   8d03590101a601010205035895a202828141008141010458898c0c0014a4
   0150fa6b4a53d5ad5fdfbe9de663e4d41ffe02501492af1425695e48bf42
   9b2d51f2ab45035824822f582000112233445566778899aabbccddeeff01
   23456789abcdeffedcba98765432100e1987d0010f020f0c0114a2035824
   822f58200123456789abcdeffedcba987654321000112233445566778899
   aabbccddeeff0e1a00012c2209584f900c0013a115781c687474703a2f2f
   6578616d706c652e636f6d2f66696c65312e62696e1502030f0c0113a115
   781c687474703a2f2f6578616d706c652e636f6d2f66696c65322e62696e
   1502030f0a49880c00030f0c01030f0c45840c001702

Appendix C.  C.  Design Rational

   In order to provide flexible behavior to constrained devices, while
   still allowing more powerful devices to use their full capabilities,
   the SUIT manifest encodes the required behavior of a Recipient
   device.  Behavior is encoded as a specialized byte code, contained in
   a CBOR list.  This promotes a flat encoding, which simplifies the
   parser.  The information encoded by this byte code closely matches
   the operations that a device will perform, which promotes ease of
   processing.  The core operations used by most update and trusted
   invocation operations are represented in the byte code.  The byte
   code can be extended by registering new operations.

   The specialized byte code approach gives benefits equivalent to those
   provided by a scripting language or conventional byte code, with two
   substantial differences.  First, the language is extremely high
   level, consisting of only the operations that a device may perform
   during update and trusted invocation of a firmware image.  Second,
   the language specifies linear behavior, without reverse branches.
   Conditional processing is supported, and parallel and out-of-order
   processing may be performed by sufficiently capable devices.

   By structuring the data in this way, the manifest processor becomes a
   very simple engine that uses a pull parser to interpret the manifest.
   This pull parser invokes a series of command handlers that evaluate a
   Condition or execute a Directive.  Most data is structured in a
   highly regular pattern, which simplifies the parser.

   The results of this allow a Recipient to implement a very small
   parser for constrained applications.  If needed, such a parser also
   allows the Recipient to perform complex updates with reduced
   overhead.  Conditional execution of commands allows a simple device
   to perform important decisions at validation-time.

   Dependency handling is vastly simplified as well.  Dependencies
   function like subroutines of the language.  When a manifest has a
   dependency, it can invoke that dependency's commands and modify their
   behavior by setting parameters.  Because some parameters come with
   security implications, the dependencies also have a mechanism to
   reject modifications to parameters on a fine-grained level.

   Developing a robust permissions system works in this model too.  The
   Recipient can use a simple ACL that is a table of Identities and
   Component Identifier permissions to ensure that operations on
   components fail unless they are permitted by the ACL.  This table can
   be further refined with individual parameters and commands.

   Capability reporting is similarly simplified.  A Recipient can report
   the Commands, Parameters, Algorithms, and Component Identifiers that
   it supports.  This is sufficiently precise for a manifest author to
   create a manifest that the Recipient can accept.

   The simplicity of design in the Recipient due to all of these
   benefits allows even a highly constrained platform to use advanced
   update capabilities.

C.1.  C.1 Design Rationale: Envelope

   The Envelope is used instead of a COSE structure for several reasons:

   1.  This enables the use of Severable Elements (Section 8.5)

   2.  This enables modular processing of manifests, particularly with
       large signatures.

   3.  This enables multiple authentication schemes.

   4.  This allows integrity verification by a dependent to be
       unaffected by adding or removing authentication structures.

   Modular processing is important because it allows a Manifest
   Processor to iterate forward over an Envelope, processing Delegation
   Chains and Authentication Blocks, retaining only intermediate values,
   without any need to seek forward and backwards in a stream until it
   gets to the Manifest itself.  This allows the use of large, Post-
   Quantum signatures without requiring retention of the signature
   itself, or seeking forward and back.

   Four authentication objects are supported by the Envelope:

   *  COSE_Sign_Tagged

   *  COSE_Sign1_Tagged

   *  COSE_Mac_Tagged

   *  COSE_Mac0_Tagged

   The SUIT Envelope allows an Update Authority or intermediary to mix
   and match any number of different authentication blocks it wants
   without any concern for modifying the integrity of another
   authentication block.  This also allows the addition or removal of an
   authentication blocks without changing the integrity check of the
   Manifest, which is important for dependency handling.  See
   Section 6.2

C.2.  C.2 Byte String Wrappers

   Byte string wrappers are used in several places in the suit manifest.
   The primary reason for wrappers it to limit the parser extent when
   invoked at different times, with a possible loss of context.

   The elements of the suit envelope are wrapped both to set the extents
   used by the parser and to simplify integrity checks by clearly
   defining the length of each element.

   The common block is re-parsed in order to find components identifiers
   from their indices, to find dependency prefixes and digests from
   their identifiers, and to find the common sequence.  The common
   sequence is wrapped so that it matches other sequences, simplifying
   the code path.

   A severed SUIT command sequence will appear in the envelope, so it
   must be wrapped as with all envelope elements.  For consistency,
   command sequences are also wrapped in the manifest.  This also allows
   the parser to discern the difference between a command sequence and a
   SUIT_Digest.

   Parameters that are structured types (arrays and maps) are also
   wrapped in a bstr.  This is so that parser extents can be set
   correctly using only a reference to the beginning of the parameter.
   This enables a parser to store a simple list of references to
   parameters that can be retrieved when needed.

Appendix D.  D.  Implementation Conformance Matrix

   This section summarizes the functionality a minimal manifest
   processor implementation needs to offer to claim conformance to this
   specification, in the absence of an application profile standard
   specifying otherwise.

   The subsequent table shows the conditions.

         +===================+=================+================+
         | Name              | Reference       | Implementation |
         +===================+=================+================+
         | Vendor Identifier | Section 8.4.8.2 | REQUIRED       |
         +-------------------+-----------------+----------------+
         | Class Identifier  | Section 8.4.8.2 | REQUIRED       |
         +-------------------+-----------------+----------------+
         | Device Identifier | Section 8.4.8.2 | OPTIONAL       |
         +-------------------+-----------------+----------------+
         | Image Match       | Section 8.4.9.2 | REQUIRED       |
         +-------------------+-----------------+----------------+
         | Component Slot    | Section 8.4.9.3 | OPTIONAL       |
         +-------------------+-----------------+----------------+
         | Abort             | Section 8.4.9.4 | OPTIONAL       |
         +-------------------+-----------------+----------------+
         | Custom Condition  | Section 8.4.9.5 | OPTIONAL       |
         +-------------------+-----------------+----------------+

                                 Table 14

   The subsequent table shows the directives.

      +=====================+==================+====================+
      | Name                | Reference        | Implementation     |
      +=====================+==================+====================+
      | Set Component Index | Section 8.4.10.1 | REQUIRED if more   |
      |                     |                  | than one component |
      +---------------------+------------------+--------------------+
      | Try Each            | Section 8.4.10.2 | OPTIONAL           |
      +---------------------+------------------+--------------------+
      | Override Parameters | Section 8.4.10.3 | REQUIRED           |
      +---------------------+------------------+--------------------+
      | Fetch               | Section 8.4.10.4 | REQUIRED for       |
      |                     |                  | Updater            |
      +---------------------+------------------+--------------------+
      | Copy                | Section 8.4.10.5 | OPTIONAL           |
      +---------------------+------------------+--------------------+
      | Run                 | Section 8.4.10.6 | REQUIRED for       |
      |                     |                  | Bootloader         |
      +---------------------+------------------+--------------------+
      | Run Sequence        | Section 8.4.10.7 | OPTIONAL           |
      +---------------------+------------------+--------------------+
      | Swap                | Section 8.4.10.8 | OPTIONAL           |
      +---------------------+------------------+--------------------+

                                  Table 15

   The subsequent table shows the parameters.

      +==================+==================+======================+
      | Name             | Reference        | Implementation       |
      +==================+==================+======================+
      | Vendor ID        | Section 8.4.8.3  | REQUIRED             |
      +------------------+------------------+----------------------+
      | Class ID         | Section 8.4.8.4  | REQUIRED             |
      +------------------+------------------+----------------------+
      | Image Digest     | Section 8.4.8.6  | REQUIRED             |
      +------------------+------------------+----------------------+
      | Image Size       | Section 8.4.8.7  | REQUIRED             |
      +------------------+------------------+----------------------+
      | Component Slot   | Section 8.4.8.8  | OPTIONAL             |
      +------------------+------------------+----------------------+
      | URI              | Section 8.4.8.9  | REQUIRED for Updater |
      +------------------+------------------+----------------------+
      | Source Component | Section 8.4.8.10 | OPTIONAL             |
      +------------------+------------------+----------------------+
      | Run Args         | Section 8.4.8.11 | OPTIONAL             |
      +------------------+------------------+----------------------+
      | Device ID        | Section 8.4.8.5  | OPTIONAL             |
      +------------------+------------------+----------------------+
      | Strict Order     | Section 8.4.8.13 | OPTIONAL             |
      +------------------+------------------+----------------------+
      | Soft Failure     | Section 8.4.8.14 | OPTIONAL             |
      +------------------+------------------+----------------------+
      | Custom           | Section 8.4.8.15 | OPTIONAL             |
      +------------------+------------------+----------------------+

                                 Table 16

Authors' Addresses

   Brendan Moran
   Arm Limited

   Email: Brendan.Moran@arm.com

   Hannes Tschofenig
   Arm Limited

   Email: hannes.tschofenig@arm.com

   Henk Birkholz
   Fraunhofer SIT

   Email: henk.birkholz@sit.fraunhofer.de
   Koen Zandberg
   Inria

   Email: koen.zandberg@inria.fr