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Versions: (draft-birkholz-sacm-coswid) 00 01 02 03 04 05 06 07 08

SACM Working Group                                           H. Birkholz
Internet-Draft                                            Fraunhofer SIT
Intended status: Standards Track                     J. Fitzgerald-McKay
Expires: May 12, 2019                              Department of Defense
                                                              C. Schmidt
                                                   The MITRE Corporation
                                                           D. Waltermire
                                                                    NIST
                                                       November 08, 2018


                      Concise Software Identifiers
                       draft-ietf-sacm-coswid-08

Abstract

   This document defines a concise representation of ISO/IEC
   19770-2:2015 Software Identification (SWID) tags that are
   interoperable with the XML schema definition of ISO/IEC 19770-2:2015
   and augmented for application in Constrained-Node Networks.  Next to
   the inherent capability of SWID tags to express arbitrary context
   information, Concise SWID (CoSWID) tags support the definition of
   additional semantics via well-defined data definitions incorporated
   by extension points.

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on May 12, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.





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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  The SWID Tag Lifecycle  . . . . . . . . . . . . . . . . .   4
     1.2.  Concise SWID Extensions . . . . . . . . . . . . . . . . .   6
     1.3.  Requirements Notation . . . . . . . . . . . . . . . . . .   7
   2.  Concise SWID Data Definition  . . . . . . . . . . . . . . . .   7
     2.1.  The concise-software-identity Object  . . . . . . . . . .   8
       2.1.1.  Determining the tag type  . . . . . . . . . . . . . .  12
       2.1.2.  concise-software-identity Co-constraints  . . . . . .  12
     2.2.  The global-attributes Group . . . . . . . . . . . . . . .  13
     2.3.  The media Object  . . . . . . . . . . . . . . . . . . . .  13
     2.4.  The entity Object . . . . . . . . . . . . . . . . . . . .  14
     2.5.  The link Object . . . . . . . . . . . . . . . . . . . . .  15
     2.6.  The software-meta Object  . . . . . . . . . . . . . . . .  17
     2.7.  The Resource Collection Definition  . . . . . . . . . . .  19
       2.7.1.  The hash-entry Array  . . . . . . . . . . . . . . . .  19
       2.7.2.  The resource-collection Group . . . . . . . . . . . .  20
       2.7.3.  The payload Object  . . . . . . . . . . . . . . . . .  23
       2.7.4.  The evidence Object . . . . . . . . . . . . . . . . .  23
     2.8.  Full CDDL Definition  . . . . . . . . . . . . . . . . . .  24
   3.  CoSWID Indexed Label Values . . . . . . . . . . . . . . . . .  29
     3.1.  Version Scheme  . . . . . . . . . . . . . . . . . . . . .  29
     3.2.  Entity Role Values  . . . . . . . . . . . . . . . . . . .  30
     3.3.  Use Values  . . . . . . . . . . . . . . . . . . . . . . .  30
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  31
     4.1.  SWID/CoSWID Version Schema Values Registry  . . . . . . .  31
     4.2.  SWID/CoSWID Entity Role Values Registry . . . . . . . . .  32
     4.3.  SWID/CoSWID Link Use Values Registry  . . . . . . . . . .  33
     4.4.  Media Type Registration . . . . . . . . . . . . . . . . .  34
       4.4.1.  swid+cbor Media Type Registration . . . . . . . . . .  34
     4.5.  CoAP Content-Format Registration  . . . . . . . . . . . .  35
     4.6.  CBOR Tag Registration . . . . . . . . . . . . . . . . . .  36
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  36
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  38
   7.  Change Log  . . . . . . . . . . . . . . . . . . . . . . . . .  38
   8.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  41
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  41



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     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  41
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  42
   Appendix A.  CoSWID Attributes for Firmware (label 60)  . . . . .  43
   Appendix B.  Signed Concise SWID Tags using COSE  . . . . . . . .  46
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  47

1.  Introduction

   SWID tags have several use-applications including but not limited to:

   o  Software Inventory Management, a part of a Software Asset
      Management [SAM] process, which requires an accurate list of
      discernible deployed software components.

   o  Vulnerability Assessment, which requires a semantic link between
      standardized vulnerability descriptions and software components
      installed on IT-assets [X.1520].

   o  Remote Attestation, which requires a link between reference
      integrity measurements (RIM) and security logs of measured
      software components [I-D.birkholz-tuda].

   SWID tags, as defined in ISO-19770-2:2015 [SWID], provide a
   standardized XML-based record format that identifies and describes a
   specific release of a software component.  Different software
   components, and even different releases of a particular software
   component, each have a different SWID tag record associated with
   them.  SWID tags are meant to be flexible and able to express a broad
   set of metadata about a software component.

   While there are very few required fields in SWID tags, there are many
   optional fields that support different use scenarios.  While a SWID
   tag consisting of only required fields might be a few hundred bytes
   in size, a tag containing many of the optional fields can be many
   orders of magnitude larger.  Thus, real-world instances of SWID tags
   can be fairly large, and the communication of SWID tags in use-
   applications such as those described earlier can cause a large amount
   of data to be transported.  This can be larger than acceptable for
   constrained devices and networks.  Concise SWID (CoSWID) tags
   significantly reduce the amount of data transported as compared to a
   typical SWID tag.  This reduction is enabled through the use of CBOR,
   which maps the human-readable labels of SWID data to more concise
   integer labels (indices).  The use of CBOR to express SWID
   information in CoSWID tags allows both CoSWID and SWID tags to be
   part of an enterprise security solution for a wider range of
   endpoints and environments.





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1.1.  The SWID Tag Lifecycle

   In addition to defining the format of a SWID tag record, ISO/IEC
   19770-2:2015 defines requirements concerning the SWID tag lifecycle.
   Specifically, when a software component is installed on an endpoint,
   that software component's SWID tag is also installed.  Likewise, when
   the software component is uninstalled or replaced, the SWID tag is
   deleted or replaced, as appropriate.  As a result, ISO/IEC
   19770-2:2015 describes a system wherein there is a correspondence
   between the set of installed software components on an endpoint, and
   the presence of the corresponding SWID tags for these components on
   that endpoint.  CoSWIDs share the same lifecycle requirements as a
   SWID tag.

   The following is an excerpt (with some modifications and reordering)
   from NIST Interagency Report (NISTIR) 8060: Guidelines for the
   Creation of Interoperable SWID Tags [SWID-GUIDANCE], which describes
   the tag types used within the lifecycle defined in ISO-19770-2:2015.
   This information is included here to provide a concise reference for
   the use of CoSWIDs in the software lifecycle.

      The SWID specification defines four types of SWID tags: primary,
      patch, corpus, and supplemental.

   1.  Primary Tag - A SWID or CoSWID tag that identifies and describes
       a software component is installed on a computing device.  A
       primary tag is intended to be installed on an endpoint along with
       the corresponding software component.

   2.  Patch Tag - A SWID or CoSWID tag that identifies and describes an
       installed patch which has made incremental changes to a software
       component installed on an endpoint.  A patch tag is intended to
       be installed on an endpoint along with the corresponding software
       component patch.

   3.  Corpus Tag - A SWID or CoSWID tag that identifies and describes
       an installable software component in its pre-installation state.
       A corpus tag can be used to represent metadata about an
       installation package or installer for a software component, a
       software update, or a patch.

   4.  Supplemental Tag - A SWID or CoSWID tag that allows additional
       information to be associated with a referenced SWID tag.  This
       helps to ensure that SWID Primary and Patch Tags provided by a
       software provider are not modified by software management tools,
       while allowing these tools to provide their own software
       metadata.




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   Note: The type of a tag is determined by specific data elements,
   which is discussed in Section 2.1.1.

      Corpus, primary, and patch tags have similar functions in that
      they describe the existence and/or presence of different types of
      software (e.g., software installers, software installations,
      software patches), and, potentially, different states of software
      components.  In contrast, supplemental tags furnish additional
      information not contained in corpus, primary, or patch tags.  All
      four tag types come into play at various points in the software
      lifecycle, and support software management processes that depend
      on the ability to accurately determine where each software
      component is in its lifecycle.

                                    +------------+
                                    v            |
  Installation     Product       Product      Product       Product
    Media      -> Installed  ->  Patched   -> Upgraded   -> Removed
   Deployed

   Corpus         Primary        Primary      xPrimary      xPrimary
                  Supplemental   Supplemental xSupplemental xSuplemental
                                 Patch        xPatch
                                              Primary
                                              Supplemental


           Figure 1: Use of Tag Types in the Software Lifecycle

      Figure 1 illustrates the steps in the software lifecycle and the
      relationships among those lifecycle events supported by the four
      types of SWID and CoSWID tags, as follows:



      *  Software Deployment.  Before the software component is
         installed (i.e., pre-installation), and while the product is
         being deployed, a corpus tag provides information about the
         installation files and distribution media (e.g., CD/DVD,
         distribution package).

      *  Software Installation.  A primary tag will be installed with
         the software component (or subsequently created) to uniquely
         identify and describe the software component.  Supplemental
         tags are created to augment primary tags with additional site-
         specific or extended information.  While not illustrated in the
         figure, patch tags may also be installed during software




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         installation to provide information about software fixes
         deployed along with the base software installation.

      *  Software Patching.  When a new patch is applied to the software
         component, a new patch tag is provided, supplying details about
         the patch and its dependencies.  While not illustrated in the
         figure, a corpus tag can also provide information about the
         patch installer, and patching dependencies that need to be
         installed before the patch.

      *  Software Upgrading.  As a software component is upgraded to a
         new version, new primary and supplemental tags replace existing
         tags, enabling timely and accurate tracking of updates to
         software inventory.  While not illustrated in the figure, a
         corpus tag can also provide information about the upgrade
         installer, and dependencies that need to be installed before
         the upgrade.

      *  Software Removal.  Upon removal of the software component,
         relevant SWID tags are removed.  This removal event can trigger
         timely updates to software inventory reflecting the removal of
         the product and any associated patch or supplemental tags.

   Note: While not fully illustrated in the figure, supplemental tags
   can be associated with any corpus, primary, or patch tag to provide
   additional metadata about an installer, installed software, or
   installed patch respectively.

   Each of the different SWID and CoSWID tag types provide different
   sets of information.  For example, a "corpus tag" is used to describe
   a software component's installation image on an installation media,
   while a "patch tag" is meant to describe a patch that modifies some
   other software component.

1.2.  Concise SWID Extensions

   This document defines the CoSWID format, a more concise
   representation of SWID information in the Concise Binary Object
   Representation (CBOR) [RFC7049].  The structure of a CoSWID is
   described via the Concise Data Definition Language (CDDL)
   [I-D.ietf-cbor-cddl].  The resulting CoSWID data definition is
   aligned in the information able to be expressed with the XML schema
   definition of ISO-19770-2:2015 [SWID].  The vocabulary, i.e., the
   CDDL names of the types and members used in the CoSWID data
   definition, are mapped to more concise labels represented as small
   integer values.  The names used in the CDDL data definition and the
   mapping to the CBOR representation using integer labels is based on




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   the vocabulary of the XML attribute and element names defined in ISO/
   IEC 19770-2:2015.

   The corresponding CoSWID data definition includes two kinds of
   augmentation.

   o  The explicit definition of types for attributes that are typically
      stored in the "any attribute" of an ISO-19770-2:2015 in XML
      representation.  These are covered in Section 2.2 and [model-any-
      element] of this document.

   o  The inclusion of extension points in the CoSWID data definition
      that allow for additional uses of CoSWID tags that go beyond the
      original scope of ISO-19770-2:2015 tags.  The following extension
      points are defined in this document:

      *  CoSWID Extension - Used to add new information structures to a
         CoSWID (defined in Section 2.1).

      *  Entity Extension - Used to add new new information structures
         to an entity (defined in Section 2.4).

      *  Payload Extension - Used to add new new information structures
         to a payload, such as new payload resource types (defined in
         Section 2.7.3).

      *  Evidence Extension - Used to add new new information structures
         to an evidence, such as new evidence resource types (defined in
         Section 2.7.4).

1.3.  Requirements Notation

   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 RFC
   2119, BCP 14 [RFC2119].

2.  Concise SWID Data Definition

   The following is a CDDL representation for a CoSWID tag.  This CDDL
   representation is intended to be parallel to the XML schema
   definition in the ISO/IEC 19770-2:2015 [SWID] specification, allowing
   both SWID and CoSWID tags to represent a common set of SWID
   information and to support all SWID tag use cases.  To achieve this
   end, the CDDL representation includes every SWID tag field and
   attribute.  The CamelCase notation used in the XML schema definition
   is changed to a hyphen-separated notation (e.g.  ResourceCollection
   is named resource-collection) in the CoSWID data definition.  This



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   deviation from the original notation used in the XML representation
   reduces ambiguity when referencing certain attributes in
   corresponding textual descriptions.  An attribute referred by its
   name in CamelCase notation explicitly relates to XML SWID tags, an
   attribute referred by its name in hyphen-separated notation
   explicitly relates to CoSWID tags.  This approach simplifies the
   composition of further work that reference both XML SWID and CoSWID
   documents.

   Human-readable names of members in the CDDL data definition are
   mapped to integer indices via a block of rules at the bottom of the
   definition.  The 67 character strings of the SWID vocabulary that
   would have to be stored or transported in full if using the original
   vocabulary are replaced.

   In CBOR, an array is encoded using bytes that identify the array, and
   the array's length or stop point (see [RFC7049]).  To make items that
   support 1 or more values, the following CDDL notion is used.

   _name_ = (_label_: _data_ / [ 2* _data_ ])

   The CDDL above allows for a more efficient CBOR encoding of the data
   when a single value is used by avoiding the need to first encode the
   array.  An array is used for two or more values.  This modeling
   pattern is used frequently in the CoSWID CDDL data definition in such
   cases.

   The following subsections describe the different parts of the CoSWID
   model.

2.1.  The concise-software-identity Object

   The CDDL for the main concise-software-identity object is as follows:


















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   concise-software-identity = {
     global-attributes,
     tag-id,
     tag-version,
     ? corpus,
     ? patch,
     ? supplemental,
     swid-name,
     ? software-version,
     ? version-scheme,
     ? media,
     ? software-meta-entry,
     entity-entry,
     ? link-entry,
     ? ( payload-entry // evidence-entry ),
     * $$coswid-extension
   }

   The following describes each child item of the concise-software-
   identity object model.

   o  global-attributes: A list of items including an optional language
      definition to support the processing of text-string values and an
      unbounded set of any-attribute items.  Described in Section 2.2.

   o  tag-id (label 0): An textual identifier uniquely referencing a
      (composite) software component.  The tag identifier MUST be
      globally unique.  There are no strict guidelines on how this
      identifier is structured, but examples include a 16 byte GUID
      (e.g.  class 4 UUID) [RFC4122], or a text string appended to a DNS
      domain name to ensure uniqueness across organizations.

   o  tag-version (label 12): An integer value that indicates if a
      specific release of a software component has more than one tag
      that can represent that specific release.  Typically, the initial
      value of this field is set to 0, and the value is monotonically
      increased for subsequent tags produced for the same software
      component release.  This item is used when a CoSWID tag producer
      creates and releases an incorrect tag that they subsequently want
      to fix, but no underlying changes have been made to the product
      the CoSWID tag represents.  This could happen if, for example, a
      patch is distributed that has a link reference that does not cover
      all the various software releases it can patch.  A newer CoSWID
      tag for that patch can be generated and the tag-version value
      incremented to indicate that the data has been updated.

   o  corpus (label 8): A boolean value that indicates if the tag
      identifies and describes an installable software component in its



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      pre-installation state.  Installable software includes a
      installation package or installer for a software component, a
      software update, or a patch.  If the CoSWID tag represents
      installable software, the corpus item MUST be set to "true".  If
      not provided the default value MUST be considered "false".

   o  patch (label 9): A boolean value that indicates if the tag
      identifies and describes an installed patch which has made
      incremental changes to a software component installed on a
      computing device.  Typically, an installed patch has made a set of
      file modifications to pre-installed software, and does not alter
      the version number or the descriptive metadata of an installed
      software component.  If a CoSWID tag is for a patch, it MUST
      contain the patch item and its value MUST be set to "true".  If
      not provided the default value MUST be considered "false".

   o  supplemental (label 11): A boolean value that indicates if the tag
      is providing additional information to be associated with another
      referenced SWID or CoSWID tag.  Tags using this item help to
      ensure that primary and patch tags provided by a software provider
      are not modified by software management tools, while allowing
      these tools to provide their own software metadata for a software
      component.  If a CoSWID tag is a supplemental tag, it MUST contain
      the supplemental item and its value MUST be set to "true".  If not
      provided the default value MUST be considered "false".

   o  swid-name (label 1): This textual item provides the software
      component name as it would typically be referenced.  For example,
      what would be seen in the add/remove software dialog in an
      operating system, or what is specified as the name of a packaged
      software component or a patch identifier name.

   o  software-version (label 13): A textual value representing the
      specific underlying release or development version of the software
      component.

   o  version-scheme (label 14): An 8-bit integer or textual value
      representing the versioning scheme used for the software-version
      item.  If an integer value is used it MUST be a value from the
      registry (see section Section 4.1 or a value in the private use
      range: 32768-65,535.

   o  media (label 10): This text value is a hint to the tag consumer to
      understand what this tag applies to.  This item represents a query
      as defined by the W3C Media Queries Recommendation (see
      http://www.w3.org/TR/css3-mediaqueries/).  A hint to the consumer
      of the link to what the target item is applicable for.  Described
      in Section 2.3.



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   o  software-meta-entry (label 5): An open-ended map of key/value data
      pairs.  A number of predefined keys can be used within this item
      providing for common usage and semantics across the industry.  The
      data definition of this entry allows for any additional attribute
      to be included, though it is recommended that industry norms for
      new attributes are defined and followed to the degree possible.
      Described in Section 2.6.

   o  entity-entry (label 2): Provides information about one or more
      organizations related to the software component referenced by this
      CoSWID tag.  Described in Section 2.4.

   o  link-entry (label 4): Provides a means to establish relationship
      arcs between the tag and another items.  A given link can be used
      to establish the relationship between tags or to reference another
      resource that is related to the CoSWID tag, e.g.  vulnerability
      database association, ROLIE feed , MUD resource , software
      download location, etc).  This is modeled after the HTML "link"
      element.  Described in Section 2.5.

   o  payload-entry (label 6): This item represents the software
      artifacts that may be installed on an endpoint when the software
      component is installed.  Note that the payload may represent a
      superset of the software artifacts installed.  Based on user
      selections at install time, an installation may not include every
      artifact that could be created or executed on the endpoint when
      the software component is installed (i.e. if a particular optional
      sub-component is not installed, the files associated with that
      software component may be included in payload, but not installed
      in the system entity).  Described in Section 2.7.3.

   o  evidence-entry (label 3): This item is used to provide results
      from a scan of a system where software that does not have a CoSWID
      tag is discovered.  In such a case, a CoSWID tag may be created by
      the discovery process when the endpoint is scanned.  This item
      represents evidence for why software is believed to be installed
      on the endpoint.  Described in Section 2.7.4.

   o  any-element-entry (label 7): A default map that can contain
      arbitrary map members and even nested maps (which would also be
      any-elements).  In essence, the any-element allows items not
      defined in this CDDL data definition to be included in a Concise
      Software Identifier.  Described in [model-any-element].








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2.1.1.  Determining the tag type

   The operational model for SWID and CoSWID tags was introduced in
   Section 1.1.  The following rules can be used to determine the type
   of a CoSWID tag.

   o  Corpus Tag: A CoSWID tag MUST be considered a corpus tag if the
      corpus item is "true".

   o  Primary Tag: A CoSWID tag MUST be considered a primary tag if the
      corpus, patch, and supplemental items are "false".

   o  Patch Tag: A CoSWID tag MUST be considered a patch tag if the
      patch item is "true" and the corpus item is "false".

   o  Supplemental Tag: A CoSWID tag MUST be considered a supplemental
      tag if the supplemental item is set to "true".

   A tag that does not match one of the above rules MUST be considered
   an invalid, unsupported tag type.

   If a patch modifies the version number or the descriptive metadata of
   the software, then a new tag representing these details SHOULD be
   installed, and the old tag SHOULD be removed.

2.1.2.  concise-software-identity Co-constraints

   o  Only one of the patch and supplemental items MUST be set to
      "true", or the patch and supplemental items MUST be set to "false"
      or be omitted.

   o  If the patch item is set to "true", the tag SHOULD contain at
      least one link with the rel(ation) item value of "patches" and an
      href item specifying an association with the software that was
      patched.

   o  If the supplemental item is set to "true", the tag SHOULD contain
      at least one link with the rel(ation) item value of "supplements"
      and an href item specifying an association with the software that
      is supplemented.

   o  If all of the corpus, patch, and supplemental items are "false",
      or if the corpus item is set to "true", then a software-version
      item MUST be included with a value set to the version of the
      software component.  This ensures that primary and corpus tags
      have an identifiable software version.





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2.2.  The global-attributes Group

   The global-attributes group provides a list of items including an
   optional language definition to support the processing of text-string
   values and an unbounded set of any-attribute items allowing for
   additional items to be provided as a general point of extension in
   the model.

   The CDDL for the global-attributes is as follows:

   global-attributes = (
     ? lang,
     * any-attribute,
   )

   label = text / int

   any-attribute = (
     label => text / int / [ 2* text ] / [ 2* int ]
   )

   The following describes each child item of this object.

   o  lang (index 15): A textual language tag that conforms with IANA
      Language Subtag Registry [RFC5646].

   o  any-attribute: This sub-group provides a means to include
      arbitrary information via label (key) item value pairs where both
      keys and values can be either a single integer or text string, or
      an array of integers or text strings.

2.3.  The media Object

   The CDDL for the entity object is as follows:

















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   media = (10: [ + [ media-expression,
                        ? [ media-operation,
                            media-expression,
                          ]
                    ]
                ])
   media-operation = text
   media-expression = media-environment / [ media-prefix,
                                            media-environment,
                                            media-attribute,
                                            media-value,
                                          ]
   media-prefix = text
   media-environment = text
   media-attribute = text
   media-value = text

   The following describes each child item of this object.

   o  TBD

2.4.  The entity Object

   The CDDL for the entity object is as follows:

   entity = {
     global-attributes,
     entity-name,
     ? reg-id,
     role,
     ? thumbprint,
     * $$entity-extension,
   }

   The following describes each child item of this object.

   o  global-attributes: The global-attributes group described in
      Section 2.2.

   o  entity-name (index 32): The text-string name of the organization
      claiming a particular role in the CoSWID tag.

   o  reg-id (index 32): The registration id is intended to uniquely
      identify a naming authority in a given scope (e.g. global,
      organization, vendor, customer, administrative domain, etc.) for
      the referenced naming authority.  The value of an registration ID
      MUST be a RFC 3986 URI.  The scope SHOULD be the scope of an




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      organization.  In a given scope, the registration id MUST be used
      consistently.

   o  role (index 33): The relationship(s) between this organization and
      this tag.  The role of an entity MAY include any role value, but
      the pre-defined roles include: "aggregator", "distributor",
      "licensor", "software-creator", and "tag-creator".  These pre-
      defined role index and text values are defined in Section 3.2.
      Use of index values instead of text for these pre-defined roles
      allows a CoSWID to be more concise.

      An entity item MUST be provided with the role of "tag-creator" for
      every CoSWID tag.  This indicates the organization that created
      the CoSWID tag.

   o  thumbprint (index 34): The value of the thumbprint item provides
      an integer-based hash algorithm identifier (hash-alg-id) and a
      byte string value (hash-value) that contains the corresponding
      hash value (i.e. the thumbprint) of the signing entities
      certificate(s).  If the hash-alg-id is not known, then the integer
      value "0" MUST be used.  This ensures parity between the SWID tag
      specification [SWID], which does not allow an algorithm to be
      identified for this field.  See Section 2.7.1 for more details on
      the use of the hash-entry data structure.

   o  $$entity-extension: This CDDL socket (see [I-D.ietf-cbor-cddl]
      section 3.9) can be used to extend the entity model, allowing
      well-formed extensions to be defined in additional CDDL
      descriptions.

2.5.  The link Object

   The CDDL for the link object is as follows:

   link = {
     global-attributes,
     ? artifact,
     href,
     ? media
     ? ownership,
     rel,
     ? media-type,
     ? use,
   }

   The following describes each child item of this object.





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   o  global-attributes: The global-attributes group described in
      Section 2.2.

   o  artifact (index: 37): For installation media (rel="installation-
      media"), this item value indicates the path of the installer
      executable or script that can be run to launch the referenced
      installation.  Items with the same artifact name should be
      considered mirrors of each other, allowing the installation media
      to be downloaded from any of the described sources.

   o  href (index 38): The link to the item being referenced.  The
      "href" item's value can point to several different things, and can
      be any of the following:

      *  If no URI scheme is provided, then the URI is to be interpreted
         as being relative to the URI of the CoSWID tag.  For example,
         "./folder/supplemental.coswid".

      *  a physical resource location with any acceptable URI scheme
         (e.g., file:// http:// https:// ftp://)

      *  a URI with "coswid:" as the scheme, which refers to another
         CoSWID by tag-id.  This URI would need to be resolved in the
         context of the endpoint by software that can lookup other
         CoSWID tags.  For example, "coswid:2df9de35-0aff-
         4a86-ace6-f7dddd1ade4c" references the tag with the tag-id
         value "2df9de35-0aff-4a86-ace6-f7dddd1ade4c".

      *  a URI with "swidpath:" as the scheme, which refers to another
         CoSIWD via an XPATH query.  This URI would need to be resolved
         in the context of the system entity via software components
         that can lookup other CoSWID tags and select the appropriate
         tag based on an XPATH query.  Examples include:

      *  swidpath://SoftwareIdentity[Entity/@regid='http://contoso.com']
         would retrieve all CoSWID tags that include an entity where the
         regid is "Contoso" or swidpath://SoftwareIdentity[Meta/@persist
         entId='b0c55172-38e9-4e36-be86-92206ad8eddb'] would match
         CoSWID tags with the persistent-id value
         "b0c55172-38e9-4e36-be86-92206ad8eddb".

      *  See XPATH query standard : http://www.w3.org/TR/xpath20/

   o  media (index 10): See media defined in Section 2.3.

   o  ownership (index 39): Determines the relative strength of
      ownership of the software components.  Valid enumerations are:
      abandon, private, shared



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   o  rel (index 40): The relationship between this CoSWID and the
      target file.  Relationships can be identified by referencing the
      IANA registration library: https://www.iana.org/assignments/link-
      relations/link-relations.xhtml.

   o  media-type (index 41): The IANA MediaType for the target resource;
      this provides the consumer with a hint of what type of resource to
      expect.  See http://www.iana.org/assignments/media-types/media-
      types.xhtml for more details.

   o  use (index 42): Determines if the target software is a hard
      requirement or not to be installed before installing the tagged
      software component.  Valid enumerations are: required,
      recommended, optional, which are defined in Section 3.3.

2.6.  The software-meta Object

   The CDDL for the software-meta object is as follows:

   software-meta = {
     global-attributes,
     ? activation-status,
     ? channel-type,
     ? colloquial-version,
     ? description,
     ? edition,
     ? entitlement-data-required,
     ? entitlement-key,
     ? generator,
     ? persistent-id,
     ? product,
     ? product-family,
     ? revision,
     ? summary,
     ? unspsc-code,
     ? unspsc-version,
   }


   The following describes each child item of this object.

   o  global-attributes: The global-attributes group described in
      Section 2.2.

   o  activation-status (index 43): Identification of the activation
      status of this software title (e.g.  Trial, Serialized, Licensed,
      Unlicensed, etc).  Typically, this is used in supplemental tags.




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   o  channel-type (index 44): Provides information on which channel
      this particular software was targeted for (e.g.  Volume, Retail,
      OEM, Academic, etc).  Typically used in supplemental tags.

   o  colloquial-version (index 45): The informal or colloquial version
      of the product (i.e. 2013).  Note that this version may be the
      same through multiple releases of a software component where the
      version specified in entity is much more specific and will change
      for each software release.

      Note that this representation of version is typically used to
      identify a group of specific software releases that are part of
      the same release/support infrastructure (i.e.  Fabrikam Office
      2013).  This version is used for string comparisons only and is
      not compared to be an earlier or later release (that is done via
      the entity version).

   o  description (index 46): A longer, detailed description of the
      software.  This description can be multiple sentences
      (differentiated from summary, which is a very short, one-sentence
      description).

   o  edition (index 47): The variation of the product (Extended,
      Enterprise, Professional, Standard, etc).

   o  entitlement-data-required (index 48): An indicator to determine if
      there should be accompanying proof of entitlement when a software
      license reconciliation is completed.

   o  entitlement-key (index 49): A vendor-specific textual key that can
      be used to reconcile the validity of an entitlement. (e.g. serial
      number, product or license key).

   o  generator (index 50): The name of the software tool that created a
      CoSWID tag.  This item is typically used if tags are created on
      the fly or via a catalog-based analysis for data found on an
      endpoint.

   o  persistent-id (index 51): A GUID used to represent products
      installed where the products are related, but may be different
      versions.

   o  product (index 52): The base name of the product.

   o  product-family (index 53): The overall product family this
      software belongs to.  Product family is not used to identify that
      a product is part of a suite, but is instead used when a set of
      products that are all related may be installed on multiple



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      different endpoints.  For example, an enterprise backup system may
      consist of a backup services, multiple different backup services
      that support mail services, databases and ERP systems, as well as
      individual software components that backup client system entities.
      In such an usage scenario, all software components that are part
      of the backup system would have the same product-family name so
      they can be grouped together in respect to reporting systems.

   o  revision (index 54): The informal or colloquial representation of
      the sub-version of the given product (ie, SP1, R2, RC1, Beta 2,
      etc).  Note that the version item will provide very exact version
      details, while the revision is intended for use in environments
      where reporting on the informal or colloquial representation of
      the software is important (for example, if for a certain business
      process, an organization recognizes that it must have, for example
      "ServicePack 1" or later of a specific product installed on all
      devices, they can use the revision data value to quickly identify
      any devices that do not meet this requirement).

      Depending on how a software organizations distributes revisions,
      this value could be specified in a primary (if distributed as an
      upgrade) or supplemental (if distributed as a patch) CoSWID tag.

   o  summary (index 55): A short (one-sentence) description of the
      software.

   o  unspsc-code (index 56): An 8 digit code that provides UNSPSC
      classification of the software component this SWID tag identifies.
      For more information see, http://www.unspsc.org/.

   o  unspsc-version (index 57): The version of the UNSPSC code used to
      define the UNSPSC code value.  For more information see,
      http://www.unspsc.org/.

2.7.  The Resource Collection Definition

2.7.1.  The hash-entry Array

   CoSWID add explicit support for the representation of hash entries
   using algorithms that are registered at the Named Information Hash
   Algorithm Registry via the hash-entry member (label 58).

   hash-entry = (58: [ hash-alg-id: int, hash-value: bstr ] )

   The number used as a value for hash-alg-id MUST refer an ID in the
   Named Information Hash Algorithm Registry; other hash algorithms MUST
   NOT be used.  The hash-value MUST represent the raw hash value of the




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   hashed resource generated using the hash algorithm indicated by the
   hash-alg-id.

2.7.2.  The resource-collection Group

   A list of items both used in evidence (discovered by an inventory
   process) and payload (installed in a system entity) content of a
   CoSWID tag document to structure and differentiate the content of
   specific CoSWID tag types.  Potential content includes directories,
   files, processes, resources or firmwares.

   The CDDL for the resource-collection group is as follows:







































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   resource-collection = (
     ? directory-entry,
     ? file-entry,
     ? process-entry,
     ? resource-entry
   )

   directory = {
     filesystem-item,
     path-elements,
   }

   file = {
     filesystem-item,
     ? size,
     ? file-version,
     ? hash-entry,
   }

   process = {
     global-attributes,
     process-name,
     ? pid,
   }

   resource = {
     global-attributes,
     type,
   }

   filesystem-item = (
     global-attributes,
     ? key,
     ? location,
     fs-name,
     ? root,
   )

   The following describes each child item or group for these groups.

   o  filesystem-item: A list of items both used in representing the
      nodes of a file-system hierarchy, i.e. directory items that allow
      one or more directories to be defined in the file structure, and
      file items that allow one or more files to be specified for a
      given location.

   o  global-attributes: The global-attributes group described in
      Section 2.2.



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   o  directory-entry (index 16): A directory item allows one or more
      directories to be defined in the file structure.

   o  file-entry (index 17): A file element that allows one or more
      files to be specified for a given location.

   o  process-entry (index 18): Provides process (software component in
      execution) information for data that will show up in a devices
      process table.

   o  resource-entry (index 19): A set of items that can be used to
      provide arbitrary resource information about an application
      installed on a system entity, or evidence collected from a system
      entity.

   o  size (index 20): The file size in bytes of the file.

   o  file-version (index 21): The version of the file.

   o  key (index 22): Files that are considered important or required
      for the use of a software component.  Typical key files would be
      those which, if not available on a system entity, would cause the
      software component not to execute or function properly.  Key files
      will typically be used to validate that a software component
      referenced by the CoSWID tag document is actually installed on a
      specific system entity.

   o  location (index 23): The directory or location where a file was
      found or can expected to be located.  This text-string is intended
      to include the filename itself.  This SHOULD be the relative path
      from the location represented by the root item.

   o  fs-name (index 24): The file name or directory name without any
      path characters.

   o  root (index 25): A system-specific root folder that the location
      item is an offset from.  If this is not specified the assumption
      is the root is the same folder as the location of the CoSWID tag.
      The text-string value represents a path expression relative to the
      CoSWID tag document location in the (composite) file-system
      hierarchy.

   o  path-elements (index 26): Provides the ability to apply a
      directory structure to the path expressions for files defined in a
      payload or evidence item.

   o  process-name (index 27): The process name as it will be found in
      the system entity's process table.



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   o  pid (index 28): The process ID for the process in execution that
      can be included in the process item as part of an evidence tag.

   o  type (index 29): The type of resource represented via a text-
      string (typically, registry-key, port or root-uri).

2.7.3.  The payload Object

   The CDDL for the payload object is as follows:

   payload = {
     global-attributes,
     resource-collection,
     * $$payload-extension
   }

   The following describes each child item of this object.

   o  global-attributes: The global-attributes group described in
      Section 2.2.

   o  resource-collection: The resource-collection group described in
      Section 2.7.2.

   o  $$payload-extension: This CDDL socket (see [I-D.ietf-cbor-cddl]
      section 3.9) can be used to extend the payload model, allowing
      well-formed extensions to be defined in additional CDDL
      descriptions.

2.7.4.  The evidence Object

   The CDDL for the evidence object is as follows:

   evidence = {
     global-attributes,
     resource-collection,
     ? date,
     ? device-id,
     * $$evidence-extension
   }
   date = (35: time)
   device-id = (36: text)

   The following describes each child item of this object.

   o  global-attributes: The global-attributes group described in
      Section 2.2.




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   o  resource-collection: The resource-collection group described in
      Section 2.7.2.

   o  date (index 35): The date and time evidence represented by an
      evidence item was gathered.

   o  device-id (index 36): A text-string identifier for a device
      evidence was gathered from.

   o  $$evidence-extension: This CDDL socket (see [I-D.ietf-cbor-cddl]
      section 3.9) can be used to extend the evidence model, allowing
      well-formed extensions to be defined in additional CDDL
      descriptions.

2.8.  Full CDDL Definition

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

concise-software-identity = {
  global-attributes,
  tag-id,
  tag-version,
  ? corpus,
  ? patch,
  ? supplemental,
  swid-name,
  ? software-version,
  ? version-scheme,
  ? media,
  ? software-meta-entry,
  entity-entry,
  ? link-entry,
  ? ( payload-entry // evidence-entry ),
  * $$coswid-extension
}

any-uri = text
label = text / int

any-attribute = (
  label => text / int / [ 2* text ] / [ 2* int ]
)

global-attributes = (
  ? lang,
  * any-attribute,



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)

resource-collection = (
  ? directory-entry,
  ? file-entry,
  ? process-entry,
  ? resource-entry
)

file = {
  filesystem-item,
  ? size,
  ? file-version,
  ? hash-entry,
}

filesystem-item = (
  global-attributes,
  ? key,
  ? location,
  fs-name,
  ? root,
)

directory = {
  filesystem-item,
  path-elements,
}

process = {
  global-attributes,
  process-name,
  ? pid,
}

resource = {
  global-attributes,
  type,
}

entity = {
  global-attributes,
  entity-name,
  ? reg-id,
  role,
  ? thumbprint,
  * $$entity-extension,
}



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evidence = {
  global-attributes,
  resource-collection,
  ? date,
  ? device-id,
  * $$evidence-extension
}

link = {
  global-attributes,
  ? artifact,
  href,
  ? media
  ? ownership,
  rel,
  ? media-type,
  ? use,
}

software-meta = {
  global-attributes,
  ? activation-status,
  ? channel-type,
  ? colloquial-version,
  ? description,
  ? edition,
  ? entitlement-data-required,
  ? entitlement-key,
  ? generator,
  ? persistent-id,
  ? product,
  ? product-family,
  ? revision,
  ? summary,
  ? unspsc-code,
  ? unspsc-version,
}

payload = {
  global-attributes,
  resource-collection,
  * $$payload-extension
}

tag-id = (0: text)
swid-name = (1: text)
entity-entry = (2: entity / [ 2* entity ])
evidence-entry = (3: evidence)



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link-entry = (4: link / [ 2* link ])
software-meta-entry = (5: software-meta / [ 2* software-meta ])
payload-entry = (6: payload)
corpus = (8: bool)
patch = (9: bool)
media = (10: [ + [ media-expression,
                     ? [ media-operation,
                         media-expression,
                       ]
                 ]
             ])
media-operation = text
media-expression = media-environment / [ media-prefix,
                                         media-environment,
                                         media-attribute,
                                         media-value,
                                       ]
media-prefix = text
media-environment = text
media-attribute = text
media-value = text
supplemental = (11: bool)
tag-version = (12: integer)
software-version = (13: text)
version-scheme = (14: version-schemes  / extended-value)
version-schemes = multipartnumeric / multipartnumeric-suffix / alphanumeric / decimal / semver
multipartnumeric = 1
multipartnumeric-suffix = 2
alphanumeric = 3
decimal = 4
semver = 16384
lang = (15: text)
directory-entry = (16: directory / [ 2* directory ])
file-entry = (17: file / [ 2* file ])
process-entry = (18: process / [ 2* process ])
resource-entry = (19: resource / [ 2* resource ])
size = (20: integer)
file-version = (21: text)
key = (22: bool)
location = (23: text)
fs-name = (24: text)
root = (25: text)
path-elements = (26: { * file-entry,
                       * directory-entry,
                     }
                )
process-name = (27: text)
pid = (28: integer)



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type = (29: text)
entity-name = (31: text)
reg-id = (32: any-uri)
role = (33: roles / extended-value / [ 2* roles / extended-value ] )
extended-value = text / uint
roles= aggregator / distributor / licensor / software-creator / tag-creator
aggregator=0
distributor=1
licensor=2
software-creator=3
tag-creator=4
thumbprint = (34: [ hash-alg-id: int,
                    hash-value: bstr,
                  ]
             )
date = (35: time)
device-id = (36: text)
artifact = (37: text)
href = (38: any-uri)
ownership = (39: shared / private / abandon / extended-value )
shared=0
private=1
abandon=2
rel = (40: rels / extended-value )
rels = ancestor / component / feature / installationmedia / packageinstaller / parent / patches / requires / see-also / supersedes / rel-supplemental
ancestor=0
component=1
feature=2
installationmedia=3
packageinstaller=4
parent=5
patches=6
requires=7
see-also=8
supersedes=9
rel-supplemental=10
media-type = (41: text)
use = (42: optional / required / recommended / extended-value )
optional=1
required=2
recommended=3
activation-status = (43: text)
channel-type = (44: text)
colloquial-version = (45: text)
description = (46: text)
edition = (47: text)
entitlement-data-required = (48: bool)
entitlement-key = (49: text)



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generator = (50: text)
persistent-id = (51: text)
product = (52: text)
product-family = (53: text)
revision = (54: text)
summary = (55: text)
unspsc-code = (56: text)
unspsc-version = (57: text)
hash-entry = (58: [ hash-alg-id: int,
                    hash-value: bstr,
                  ]
             )

3.  CoSWID Indexed Label Values

3.1.  Version Scheme

   The following table contains an initial set of values for use in the
   version-scheme item for the version schemes defined in the ISO/IEC
   19770-2:2015 [SWID] specification.  Index value in parens indicates
   the index value to use in the version-scheme item.

   +-------+-------------------------+---------------------------------+
   | Index | Role Name               | Definition                      |
   +-------+-------------------------+---------------------------------+
   | 0     | Reserved                |                                 |
   |       |                         |                                 |
   | 1     | multipartnumeric        | Numbers separated by dots,      |
   |       |                         | where the numbers are           |
   |       |                         | interpreted as integers         |
   |       |                         | (e.g.,1.2.3, 1.4.5,             |
   |       |                         | 1.2.3.4.5.6.7)                  |
   |       |                         |                                 |
   | 2     | multipartnumeric+suffix | Numbers separated by dots,      |
   |       |                         | where the numbers are           |
   |       |                         | interpreted as integers with an |
   |       |                         | additional string suffix(e.g.,  |
   |       |                         | 1.2.3a)                         |
   |       |                         |                                 |
   | 3     | alphanumeric            | Strictly a string, sorting is   |
   |       |                         | done alphanumerically           |
   |       |                         |                                 |
   | 4     | decimal                 | A floating point number (e.g.,  |
   |       |                         | 1.25 is less than 1.3)          |
   |       |                         |                                 |
   | 16384 | semver                  | Follows the [SEMVER]            |
   |       |                         | specification                   |
   +-------+-------------------------+---------------------------------+



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   The values above are registered in the "SWID/CoSWID Version Schema
   Values" registry defined in section Section 4.1.  Additional valid
   values will likely be registered over time in this registry.
   Additionally, the index values 32768 through 65535 have been reserved
   for private use.

3.2.  Entity Role Values

   The following table indicates the index value to use for the entity
   roles defined in the ISO/IEC 19770-2:2015 [SWID] specification.

   | Index | Role Name | Definition |-- | 0 | Reserved | | 1 |
   tagCreator | The person or organization that created the containing
   SWID or CoSWID tag | 2 | softwareCreator | From [SAM], "person or
   organization that creates a software product (3.46) or package" | 3 |
   aggregator | From {{SWID}, "An organization or system that
   encapsulates software from their own and/or other organizations into
   a different distribution process (as in the case of virtualization),
   or as a completed system to accomplish a specific task (as in the
   case of a value added reseller)." | 4 | distributor | From [SWID],
   "An entity that furthers the marketing, selling and/or distribution
   of software from the original place of manufacture to the ultimate
   user without modifying the software, its packaging or its
   labelling." | 5 | licensor | From [SAM] as "software licensor",
   "person or organization who owns or holds the rights to issue a
   software license for a specific software package"

   The values above are registered in the "SWID/CoSWID Entity Role
   Values" registry defined in section Section 4.2.  Additional valid
   values will likely be registered over time.  Additionally, the index
   values 128 through 255 have been reserved for private use.

3.3.  Use Values

   The following table indicates the index value to use for the link use
   item (see Section 2.5), which is also defined in the ISO/IEC
   19770-2:2015 [SWID] specification.














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   +-------+-------------+---------------------------------------------+
   | Index | Use Type    | Definition                                  |
   +-------+-------------+---------------------------------------------+
   | 0     | Reserved    |                                             |
   |       |             |                                             |
   | 1     | optional    | From {{SWID}, "Not absolutely required; the |
   |       |             | [Link]'d software is installed only when    |
   |       |             | specified."                                 |
   |       |             |                                             |
   | 2     | required    | From {{SWID}, "The [Link]'d software is     |
   |       |             | absolutely required for an operation        |
   |       |             | software installation."                     |
   |       |             |                                             |
   | 3     | recommended | From {{SWID}, "Not absolutely required; the |
   |       |             | [Link]'d software is installed unless       |
   |       |             | specified otherwise."                       |
   +-------+-------------+---------------------------------------------+

   The values above are registered in the "SWID/CoSWID Link Use Values"
   registry defined in section Section 4.3.  Additional valid values
   will likely be registered over time.  Additionally, the index values
   128 through 255 have been reserved for private use.

4.  IANA Considerations

   This document will include requests to IANA:

   o  Integer indices for SWID content attributes and information
      elements.

   o  Content-Type for CoAP to be used in COSE.

   This document has a number of IANA considerations, as described in
   the following subsections.

4.1.  SWID/CoSWID Version Schema Values Registry

   This document uses unsigned 16-bit index values to version-scheme
   item values.  The initial set of version-scheme values are derived
   from the textual version scheme names defined in the ISO/IEC
   19770-2:2015 specification [SWID].

   This document defines a new a new registry entitled "SWID/CoSWID
   Version Schema Values".  Future registrations for this registry are
   to be made based on [RFC8126] as follows:






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                +-------------+--------------------------+
                | Range       | Registration Procedures  |
                +-------------+--------------------------+
                | 0-16383     | Standards Action         |
                |             |                          |
                | 16384-32767 | Specification Required   |
                |             |                          |
                | 32768-65535 | Reserved for Private Use |
                +-------------+--------------------------+

   Initial registrations for the SWID/CoSWID Version Schema Values
   registry are provided below.

       +-------------+--------------------------+-----------------+
       | Index       | Role Name                | Specification   |
       +-------------+--------------------------+-----------------+
       | 0           | Reserved                 |                 |
       |             |                          |                 |
       | 1           | multipartnumeric         | See Section 3.1 |
       |             |                          |                 |
       | 2           | multipartnumeric+suffix  | See Section 3.1 |
       |             |                          |                 |
       | 3           | alphanumeric             | See Section 3.1 |
       |             |                          |                 |
       | 4           | decimal                  | See Section 3.1 |
       |             |                          |                 |
       | 5-16383     | Unassigned               |                 |
       |             |                          |                 |
       | 16384       | semver                   | [SEMVER]        |
       |             |                          |                 |
       | 16385-32767 | Unassigned               |                 |
       |             |                          |                 |
       | 32768-65535 | Reserved for Private Use |                 |
       +-------------+--------------------------+-----------------+

4.2.  SWID/CoSWID Entity Role Values Registry

   This document uses unsigned 8-bit index values to represent entity-
   role values.  The initial set of Entity roles are derived from the
   textual role names defined in the ISO/IEC 19770-2:2015 specification
   [SWID].

   This document defines a new a new registry entitled "SWID/CoSWID
   Entity Role Values".  Future registrations for this registry are to
   be made based on [RFC8126] as follows:






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                  +---------+--------------------------+
                  | Range   | Registration Procedures  |
                  +---------+--------------------------+
                  | 0-31    | Standards Action         |
                  |         |                          |
                  | 32-127  | Specification Required   |
                  |         |                          |
                  | 128-255 | Reserved for Private Use |
                  +---------+--------------------------+

   Initial registrations for the SWID/CoSWID Entity Role Values registry
   are provided below.

         +---------+--------------------------+-----------------+
         | Index   | Role Name                | Specification   |
         +---------+--------------------------+-----------------+
         | 0       | Reserved                 |                 |
         |         |                          |                 |
         | 1       | tagCreator               | See Section 3.2 |
         |         |                          |                 |
         | 2       | softwareCreator          | See Section 3.2 |
         |         |                          |                 |
         | 3       | aggregator               | See Section 3.2 |
         |         |                          |                 |
         | 4       | distributor              | See Section 3.2 |
         |         |                          |                 |
         | 5       | licensor                 | See Section 3.2 |
         |         |                          |                 |
         | 6-31    | Unassigned               |                 |
         |         |                          |                 |
         | 32-127  | Unassigned               |                 |
         |         |                          |                 |
         | 128-255 | Reserved for Private Use |                 |
         +---------+--------------------------+-----------------+

4.3.  SWID/CoSWID Link Use Values Registry

   This document uses unsigned 8-bit index values to represent link-use
   values.  The initial set of Link use values are derived from the
   textual names defined in the ISO/IEC 19770-2:2015 specification
   [SWID].

   This document defines a new a new registry entitled "SWID/CoSWID Link
   Use Values".  Future registrations for this registry are to be made
   based on [RFC8126] as follows:






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                  +---------+--------------------------+
                  | Range   | Registration Procedures  |
                  +---------+--------------------------+
                  | 0-31    | Standards Action         |
                  |         |                          |
                  | 32-127  | Specification Required   |
                  |         |                          |
                  | 128-255 | Reserved for Private Use |
                  +---------+--------------------------+

   Initial registrations for the SWID/CoSWID Entity Role Values registry
   are provided below.

         +---------+--------------------------+-----------------+
         | Index   | Role Name                | Specification   |
         +---------+--------------------------+-----------------+
         | 0       | Reserved                 |                 |
         |         |                          |                 |
         | 1       | optional                 | See Section 3.3 |
         |         |                          |                 |
         | 2       | required                 | See Section 3.3 |
         |         |                          |                 |
         | 3       | recommended              | See Section 3.3 |
         |         |                          |                 |
         | 4-31    | Unassigned               |                 |
         |         |                          |                 |
         | 32-127  | Unassigned               |                 |
         |         |                          |                 |
         | 128-255 | Reserved for Private Use |                 |
         +---------+--------------------------+-----------------+

4.4.  Media Type Registration

4.4.1.  swid+cbor Media Type Registration

   Type name: application

   Subtype name: swid+cbor

   Required parameters: none

   Optional parameters: none

   Encoding considerations: Must be encoded as using [RFC7049].  See
   RFC-AAAA for details.

   Security considerations: See Section 5 of RFC-AAAA.




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   Interoperability considerations: Applications MAY ignore any key
   value pairs that they do not understand.  This allows backwards
   compatible extensions to this specification.

   Published specification: RFC-AAAA

   Applications that use this media type: The type is used by Software
   asset management systems, Vulnerability assessment systems, and in
   applications that use remote integrity verification.

   Fragment identifier considerations: Fragment identification for
   application/swid+cbor is supported by using fragment identifiers as
   specified by RFC-AAAA.  [Section to be defined]

   Additional information:

   Magic number(s): first five bytes in hex: da 53 57 49 44

   File extension(s): coswid

   Macintosh file type code(s): none

   Macintosh Universal Type Identifier code: org.ietf.coswid conforms to
   public.data

   Person & email address to contact for further information: Henk
   Birkholz <henk.birkholz@sit.fraunhofer.de>

   Intended usage: COMMON

   Restrictions on usage: None

   Author: Henk Birkholz <henk.birkholz@sit.fraunhofer.de>

   Change controller: IESG

4.5.  CoAP Content-Format Registration

   IANA is requested to assign a CoAP Content-Format ID for the CoSWID
   media type in the "CoAP Content-Formats" sub-registry, from the "IETF
   Review or IESG Approval" space (256..999), within the "CoRE
   Parameters" registry [RFC7252]:









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         +-----------------------+----------+-------+-----------+
         | Media type            | Encoding | ID    | Reference |
         +-----------------------+----------+-------+-----------+
         | application/swid+cbor | -        | TBDcf | RFC-AAAA  |
         +-----------------------+----------+-------+-----------+

                     Table 1: CoAP Content-Format IDs

4.6.  CBOR Tag Registration

   IANA is requested to allocate a tag in the CBOR Tags Registry,
   preferably with the specific value requested:

   +------------+----------+-------------------------------------------+
   | Tag        | Data     | Semantics                                 |
   |            | Item     |                                           |
   +------------+----------+-------------------------------------------+
   | 1398229316 | map      | Concise Software Identifier (CoSWID)      |
   |            |          | [RFC-AAAA]                                |
   +------------+----------+-------------------------------------------+

5.  Security Considerations

   SWID and CoSWID tags contain public information about software
   components and, as such, do not need to be protected against
   disclosure on an endpoint.  Similarly, SWID tags are intended to be
   easily discoverable by applications and users on an endpoint in order
   to make it easy to identify and collect all of an endpoint's SWID
   tags.  As such, any security considerations regarding SWID tags focus
   on the application of SWID tags to address security challenges, and
   the possible disclosure of the results of those applications.

   A signed SWID tag whose signature has been validated can be relied
   upon to be unchanged since it was signed.  If the SWID tag was
   created by the software provider, is signed, and the software
   provider can be authenticated as the originator of the signature,
   then the tag can be considered authoritative.  In this way, an
   authoritative SWID tag contains information about a software product
   provided by the maintainer of the product, who is expected to be an
   expert in their own product.  Thus, authoritative SWID tags can be
   trusted to represent authoritative information about the software
   product.  Having an authoritative SWID tag can be useful when the
   information in the tag needs to be trusted, such as when the tag is
   being used to convey reference integrity measurements for software
   components.  By contrast, the data contained in unsigned tags cannot
   be trusted to be unmodified.





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   SWID tags are designed to be easily added and removed from an
   endpoint along with the installation or removal of software
   components.  On endpoints where addition or removal of software
   components is tightly controlled, the addition or removal of SWID
   tags can be similarly controlled.  On more open systems, where many
   users can manage the software inventory, SWID tags may be easier to
   add or remove.  On such systems, it may be possible to add or remove
   SWID tags in a way that does not reflect the actual presence or
   absence of corresponding software components.  Similarly, not all
   software products automatically install SWID tags, so products may be
   present on an endpoint without providing a corresponding SWID tag.
   As such, any collection of SWID tags cannot automatically be assumed
   to represent either a complete or fully accurate representation of
   the software inventory of the endpoint.  However, especially on
   devices that more strictly control the ability to add or remove
   applications, SWID tags are an easy way to provide an preliminary
   understanding of that endpoint's software inventory.

   Any report of an endpoint's SWID tag collection provides information
   about the software inventory of that endpoint.  If such a report is
   exposed to an attacker, this can tell them which software products
   and versions thereof are present on the endpoint.  By examining this
   list, the attacker might learn of the presence of applications that
   are vulnerable to certain types of attacks.  As noted earlier, SWID
   tags are designed to be easily discoverable by an endpoint, but this
   does not present a significant risk since an attacker would already
   need to have access to the endpoint to view that information.
   However, when the endpoint transmits its software inventory to
   another party, or that inventory is stored on a server for later
   analysis, this can potentially expose this information to attackers
   who do not yet have access to the endpoint.  As such, it is important
   to protect the confidentiality of SWID tag information that has been
   collected from an endpoint, not because those tags individually
   contain sensitive information, but because the collection of SWID
   tags and their association with an endpoint reveals information about
   that endpoint's attack surface.

   Finally, both the ISO-19770-2:2015 XML schema definition and the
   Concise SWID data definition allow for the construction of "infinite"
   SWID tags or SWID tags that contain malicious content with the intent
   if creating non-deterministic states during validation or processing
   of SWID tags.  While software product vendors are unlikely to do
   this, SWID tags can be created by any party and the SWID tags
   collected from an endpoint could contain a mixture of vendor and non-
   vendor created tags.  For this reason, tools that consume SWID tags
   ought to treat the tag contents as potentially malicious and should
   employ input sanitizing on the tags they ingest.




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6.  Acknowledgments

7.  Change Log

   Changes from version 06 to version 07:

   o  Added type choices/enumerations based on textual definitions in
      19770-2:2015

   o  Added value registry request

   o  Added media type registration request

   o  Added content format registration request

   o  Added CBOR tag registration request

   o  Removed RIM appedix to be addressed in complementary draft

   o  Removed CWT appendix

   o  Flagged firmware resource colletion appendix for revision

   o  Made use of terminology more consistent

   o  Better defined use of extension points in the CDDL

   o  Added definitions for indexed values

   o  Added IANA registry for Link use indexed values

   Changes from version 05 to version 06:

   o  Improved quantities

   o  Included proposals for implicet enumerations that were NMTOKENS

   o  Added extension points

   o  Improved exemplary firmware-resource extension

   Changes from version 04 to version 05:

   o  Clarified language around SWID and CoSWID to make more consistent
      use of these terms.

   o  Added language describing CBOR optimizations for single vs. arrays
      in the model front matter.



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   o  Fixed a number of grammatical, spelling, and wording issues.

   o  Documented extension points that use CDDL sockets.

   o  Converted IANA registration tables to markdown tables, reserving
      the 0 value for use when a value is not known.

   o  Updated a number of references to their current versions.

   Changes from version 03 to version 04:

   o  Re-index label values in the CDDL.

   o  Added a section describing the CoSWID model in detail.

   o  Created IANA registries for entity-role and version-scheme

   Changes from version 02 to version 03:

   o  Updated CDDL to allow for a choice between a payload or evidence

   o  Re-index label values in the CDDL.

   o  Added item definitions

   o  Updated references for COSE, CBOR Web Token, and CDDL.

   Changes from version 01 to version 02:

   o  Added extensions for Firmware and CoSWID use as Reference
      Integrity Measurements (CoSWID RIM)

   o  Changes meta handling in CDDL from use of an explicit use of items
      to a more flexible unconstrained collection of items.

   o  Added sections discussing use of COSE Signatures and CBOR Web
      Tokens

   Changes from version 00 to version 01:

   o  Added CWT usage for absolute SWID paths on a device

   o  Fixed cardinality of type-choices including arrays

   o  Included first iteration of firmware resource-collection

   Changes since adopted as a WG I-D -00:




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   o  Removed redundant any-attributes originating from the ISO-
      19770-2:2015 XML schema definition

   o  Fixed broken multi-map members

   o  Introduced a more restrictive item (any-element-map) to represent
      custom maps, increased restriction on types for the any-attribute,
      accordingly

   o  Fixed X.1520 reference

   o  Minor type changes of some attributes (e.g.  NMTOKENS)

   o  Added semantic differentiation of various name types (e,g. fs-
      name)

   Changes from version 00 to version 01:

   o  Ambiguity between evidence and payload eliminated by introducing
      explicit members (while still

   o  allowing for "empty" SWID tags)

   o  Added a relatively restrictive COSE envelope using cose_sign1 to
      define signed CoSWID (single signer only, at the moment)

   o  Added a definition how to encode hashes that can be stored in the
      any-member using existing IANA tables to reference hash-algorithms

   Changes from version 01 to version 02:

   o  Enforced a more strict separation between the core CoSWID
      definition and additional usage by moving content to corresponding
      appendices.

   o  Removed artifacts inherited from the reference schema provided by
      ISO (e.g.  NMTOKEN(S))

   o  Simplified the core data definition by removing group and type
      choices where possible

   o  Minor reordering of map members

   o  Added a first extension point to address requested flexibility for
      extensions beyond the any-element






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8.  Contributors

9.  References

9.1.  Normative References

   [I-D.ietf-ace-cbor-web-token]
              Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,
              "CBOR Web Token (CWT)", draft-ietf-ace-cbor-web-token-15
              (work in progress), March 2018.

   [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>.

   [RFC4108]  Housley, R., "Using Cryptographic Message Syntax (CMS) to
              Protect Firmware Packages", RFC 4108,
              DOI 10.17487/RFC4108, August 2005,
              <https://www.rfc-editor.org/info/rfc4108>.

   [RFC5646]  Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
              Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
              September 2009, <https://www.rfc-editor.org/info/rfc5646>.

   [RFC7049]  Bormann, C. and P. Hoffman, "Concise Binary Object
              Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
              October 2013, <https://www.rfc-editor.org/info/rfc7049>.

   [RFC7252]  Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
              Application Protocol (CoAP)", RFC 7252,
              DOI 10.17487/RFC7252, June 2014,
              <https://www.rfc-editor.org/info/rfc7252>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

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

   [SAM]      "Information technology - Software asset management - Part
              5: Overview and vocabulary", ISO/IEC 19770-5:2015,
              November 2013.





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   [SEMVER]   Preston-Werner, T., "Semantic Versioning 2.0.0", n.d.,
              <https://semver.org/spec/v2.0.0.html>.

   [SWID]     "Information technology - Software asset management - Part
              2: Software identification tag", ISO/IEC 19770-2:2015,
              October 2015.

   [SWID-GUIDANCE]
              Waltermire, D., Cheikes, B., Feldman, L., and G. Witte,
              "Guidelines for the Creation of Interoperable Software
              Identification (SWID) Tags", NISTIR 8060, April 2016,
              <https://doi.org/10.6028/NIST.IR.8060>.

   [X.1520]   "Recommendation ITU-T X.1520 (2014), Common
              vulnerabilities and exposures", April 2011.

9.2.  Informative References

   [I-D.birkholz-tuda]
              Fuchs, A., Birkholz, H., McDonald, I., and C. Bormann,
              "Time-Based Uni-Directional Attestation", draft-birkholz-
              tuda-04 (work in progress), March 2017.

   [I-D.ietf-cbor-cddl]
              Birkholz, H., Vigano, C., and C. Bormann, "Concise data
              definition language (CDDL): a notational convention to
              express CBOR and JSON data structures", draft-ietf-cbor-
              cddl-05 (work in progress), August 2018.

   [I-D.ietf-sacm-rolie-softwaredescriptor]
              Banghart, S. and D. Waltermire, "Definition of the ROLIE
              Software Descriptor Extension", draft-ietf-sacm-rolie-
              softwaredescriptor-03 (work in progress), July 2018.

   [I-D.ietf-sacm-terminology]
              Birkholz, H., Lu, J., Strassner, J., Cam-Winget, N., and
              A. Montville, "Security Automation and Continuous
              Monitoring (SACM) Terminology", draft-ietf-sacm-
              terminology-15 (work in progress), June 2018.

   [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>.

   [RFC4949]  Shirey, R., "Internet Security Glossary, Version 2",
              FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
              <https://www.rfc-editor.org/info/rfc4949>.



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   [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>.

Appendix A.  CoSWID Attributes for Firmware (label 60)

   NOTE: this appendix is subject to revision or removal based on
   potential convergence of:

   o  draft-moran-suit-manifest, and

   o  draft-birkholz-suit-coswid-manifest

   The ISO-19770-2:2015 specification of SWID tags assumes the existence
   of a file system a software component is installed and stored in.  In
   the case of constrained-node networks [RFC7228] or network equipment
   this assumption might not apply.  Concise software instances in the
   form of (modular) firmware are often stored directly on a block
   device that is a hardware component of the constrained-node or
   network equipment.  Multiple differentiable block devices or
   segmented block devices that contain parts of modular firmware
   components (potentially each with their own instance version) are
   already common at the time of this writing.

   The optional attributes that annotate a firmware package address
   specific characteristics of pieces of firmware stored directly on a
   block-device in contrast to software deployed in a file-system.  In
   essence, trees of relative path-elements expressed by the directory
   and file structure in CoSWID tags are typically unable to represent
   the location of a firmware on a constrained-node (small thing).  The
   composite nature of firmware and also the actual composition of small
   things require a set of attributes to address the identification of
   the correct component in a composite thing for each individual piece
   of firmware.  A single component also potentially requires a number
   of distinct firmware parts that might depend on each other
   (versions).  These dependencies can be limited to the scope of the
   component itself or extend to the scope of a larger composite device.
   In addition, it might not be possible (or feasible) to store a CoSWID
   tag document (permanently) on a small thing along with the
   corresponding piece of firmware.

   To address the specific characteristics of firmware, the extension
   points "$$payload-extension" and "$$evidence-extension" are used to
   allow for an additional type of resource description--firmware-
   entry--thereby increasing the self-descriptiveness and flexibility of
   CoSWID.  The optional use of the extension points "$$payload-




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   extension" and "$$evidence-extension" in respect to firmware MUST
   adhere to the following CDDL data definition.

<CODE BEGINS>
$$payload-extension  //= (suit.manifest-entry,)
$$evidence-extension  //= (suit.manifest-entry,)

suit-manifest = {
  suit.manifest-version,
  suit.digest-info,
  suit.text-reference,
  suit.nonce,
  suit.sequence-number,
  ? suit.pre-condition,
  ? suit.post-condition,
  ? suit.directives,
  ? suit.resources,
  ? suit.processors,
  ? suit.targets,
  ? suit.extensions,
}

suit.manifest-entry = (59: suit-manifest / [ 2* suit-manifest ] )
suit.manifest-version = (60: 1)
suit.digest-info = (61: [ suit.digest-algorithm,
                          ? suit.digest-parameters,
                        ]
                   )
suit.digest-algorithm = uint
suit.digest-parameters = bytes
suit.text-reference = (62: bytes)
suit.nonce = (63: bytes)
suit.sequence-number = (64: uint)
suit.pre-condition = (suit.id-condition // suit.time-condition // suit.image-condition // suit.custom-condition)
suit.post-condition = (suit.image-condition // suit.custom-condition)
suit.id-condition = (65: [ + [ suit.vendor / suit.class / suit.device,
                               suit.uuid,
                             ]
                         ]
                    )
suit.vendor = 0
suit.class = 1
suit.device = 2
suit.uuid = bstr .size 16
suit.time-condition = (66: [ + [ suit.install-after / suit.best-before,
                                 suit.timestamp,
                               ]
                           ]



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                      )
suit.install-after = 0
suit.best-before = 1
suit.timestamp = uint .size 8
suit.image-condition = (67: [ + [ suit.current-content / suit.not-current-content,
                                  suit.storage-identifier,
                                  ? suit.digest,
                                ]
                            ]
                       )
suit.current-content = 0
suit.not-current-content = 1
suit.digest = bytes
suit.storage-identifier = bytes
suit.custom-condition = (68: [ nint,
                               suit.condition-parameters,
                             ]
                        )
suit.condition-parameters = bytes
suit.directives = (69: { + int => bytes } )
suit.resources = (70: [ + [ suit.resource-type,
                            suit.uri-list,
                            suit.digest,
                            suit.onode,
                            ? suit.size,
                          ]
                      ]
                 )
suit.resource-type = suit.payload / suit.dependency / suit.key / suit.alias
suit.payload = 0
suit.dependency = 1
suit.key = 2
suit.alias = 3
suit.uri-list = { + int => text }
suit.size = uint
suit.onode = bytes
suit.processors = (71: [ + [ suit.decrypt / suit.decompress / suit.undiff / suit.relocate / suit.unrelocate,
                             suit.parameters,
                             suit.inode,
                             suit.onode,
                           ]
                       ]
                  )
suit.decrypt = 0
suit.decompress = 1
suit.undiff = 2
suit.relocate = 3
suit.unrelocate = 4



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suit.parameters = bytes
suit.inode = bytes
suit.targets = (72: [ + [ suit.component-id,
                          suit.storage-identifier,
                          suit.inode,
                          ? suit.encoding,
                        ]
                    ]
                )
suit.component-id = [ + bytes ]
suit.encoding = bytes
suit.extensions = (73: { + int => bytes } )
<CODE ENDS>

   The members of the firmware group that constitutes the content of the
   firmware-entry is based on the metadata about firmware Described in
   [RFC4108].  As with every semantic differentiation that is supported
   by the resource-collection type, the use of firmware-entry is
   optional.  It is REQUIRED not to instantiate more than one firmware-
   entry, as the firmware group is used in a map and therefore only
   allows for unique labels.

   The optional cms-firmware-package member allows to include the actual
   firmware in the CoSWID tag that also expresses its metadata as a
   byte-string.  This option enables a CoSWID tag to be used as a
   container or wrapper that composes both firmware and its metadata in
   a single document (which again can be signed, encrypted and/or
   compressed).  In consequence, a CoSWID tag about firmware can be
   conveyed as an identifying document across endpoints or used as a
   reference integrity measurement as usual.  Alternatively, it can also
   convey an actual piece of firmware, serve its intended purpose as a
   SWID tag and then - due to the lack of a location to store it - be
   discarded.

Appendix B.  Signed Concise SWID Tags using COSE

   SWID tags, as defined in the ISO-19770-2:2015 XML schema, can include
   cryptographic signatures to protect the integrity of the SWID tag.
   In general, tags are signed by the tag creator (typically, although
   not exclusively, the vendor of the software component that the SWID
   tag identifies).  Cryptographic signatures can make any modification
   of the tag detectable, which is especially important if the integrity
   of the tag is important, such as when the tag is providing reference
   integrity measurements for files.

   The ISO-19770-2:2015 XML schema uses XML DSIG to support
   cryptographic signatures.  CoSWID tags require a different signature
   scheme than this.  COSE (CBOR Object Signing and Encryption) provides



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   the required mechanism [RFC8152].  Concise SWID can be wrapped in a
   COSE Single Signer Data Object (cose-sign1) that contains a single
   signature.  The following CDDL defines a more restrictive subset of
   header attributes allowed by COSE tailored to suit the requirements
   of Concise SWID.

<CODE BEGINS>
signed-coswid = #6.997(COSE-Sign1-coswid) ; see TBS7 in current COSE I-D

label = int / tstr  ; see COSE I-D 1.4.
values = any        ; see COSE I-D 1.4.

unprotected-signed-coswid-header = {
    1 => int,                   ; algorithm identifier
    3 => "application/coswid",  ; request for CoAP IANA registry to become an int
    * label => values,
}

protected-signed-coswid-header = {
    4 => bstr,                  ; key identifier
    * label => values,
}

COSE-Sign1-coswid = [
    protected: bstr .cbor protected-signed-coswid-header,
    unprotected: unprotected-signed-coswid-header,
    payload: bstr .cbor concise-software-identity,
    signature: bstr,
]
<CODE ENDS>

Authors' Addresses

   Henk Birkholz
   Fraunhofer SIT
   Rheinstrasse 75
   Darmstadt  64295
   Germany

   Email: henk.birkholz@sit.fraunhofer.de











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   Jessica Fitzgerald-McKay
   Department of Defense
   9800 Savage Road
   Ft. Meade, Maryland
   USA

   Email: jmfitz2@nsa.gov


   Charles Schmidt
   The MITRE Corporation
   202 Burlington Road
   Bedford, Maryland  01730
   USA

   Email: cmschmidt@mitre.org


   David Waltermire
   National Institute of Standards and Technology
   100 Bureau Drive
   Gaithersburg, Maryland  20877
   USA

   Email: david.waltermire@nist.gov


























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