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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: September 6, 2018                         Department of Defense
                                                              C. Schmidt
                                                   The MITRE Corporation
                                                           D. Waltermire
                                                                    NIST
                                                          March 05, 2018


                      Concise Software Identifiers
                       draft-ietf-sacm-coswid-04

Abstract

   This document defines a concise representation of ISO/IEC
   19770-2:2015 Software Identifiers (SWID tags) that is 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,
   CoSWID 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 September 6, 2018.

Copyright Notice

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

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents



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   (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  . . . . . . . . . . . . . . . . .   3
     1.2.  Concise SWID Extensions . . . . . . . . . . . . . . . . .   6
     1.3.  Requirements Notation . . . . . . . . . . . . . . . . . .   6
   2.  Concise SWID Data Definition  . . . . . . . . . . . . . . . .   7
     2.1.  The concise-software-identity Object  . . . . . . . . . .   7
       2.1.1.  Determining the tag type  . . . . . . . . . . . . . .  11
       2.1.2.  concise-software-identity Co-constraints  . . . . . .  12
     2.2.  The global-attributes Group . . . . . . . . . . . . . . .  12
     2.3.  The any-element-entry . . . . . . . . . . . . . . . . . .  13
     2.4.  The entity Object . . . . . . . . . . . . . . . . . . . .  13
     2.5.  The link Object . . . . . . . . . . . . . . . . . . . . .  15
     2.6.  The software-meta Object  . . . . . . . . . . . . . . . .  16
     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  . . . . . . . . . . . . . . . . .  22
       2.7.4.  The evidence Object . . . . . . . . . . . . . . . . .  23
     2.8.  Full CDDL Definition  . . . . . . . . . . . . . . . . . .  23
   3.  CoSWID Indexed Label Values . . . . . . . . . . . . . . . . .  28
     3.1.  Version Scheme  . . . . . . . . . . . . . . . . . . . . .  28
     3.2.  Entity Role Values  . . . . . . . . . . . . . . . . . . .  28
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  29
     4.1.  SWID/CoSWID Version Schema Values Registry  . . . . . . .  29
     4.2.  SWID/CoSWID Entity Role Values Registry . . . . . . . . .  30
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  30
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  32
   7.  Change Log  . . . . . . . . . . . . . . . . . . . . . . . . .  32
   8.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  34
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  34
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  34
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  35
   Appendix A.  CoSWID Attributes for Firmware (label 60)  . . . . .  35
   Appendix B.  Signed Concise SWID Tags using COSE  . . . . . . . .  38
   Appendix C.  CoSWID used as Reference Integrity Measurements
                (CoSWID RIM) . . . . . . . . . . . . . . . . . . . .  39
   Appendix D.  CBOR Web Token for Concise SWID Tags . . . . . . . .  40
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  40



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1.  Introduction

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

   o  Software Inventory Management, a part of the 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 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 format for a record 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.

   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.  CoSWID tags significantly reduce the amount of data
   transported as compared to a typical SWID tag.  This reduction is
   enable through the use of CBOR, which maps human-readable labels of
   that content to more concise integer labels (indices).  This allows
   SWID tags to be part of an enterprise security solution for a wider
   range of endpoints and environments.

1.1.  The SWID Tag Lifecycle

   In addition to defining the format of these records, ISO/IEC
   19770-2:2015 defines requirements concerning the SWID tag life-cycle.
   Specifically, when a software component is installed on an endpoint,
   that product's SWID tag is also installed.  Likewise, when the
   product 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 products on an endpoint, and the presence on
   that endpoint of the SWID tags corresponding to those products.

   The following is an excerpt (with some modifications and reordering)
   from NIST Interagency Report (NISTIR) 8060: Guidelines for the



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   Creation of Interoperable SWID Tags [SWID-GUIDANCE], which describes
   the tag types used within the lifecycle defined in ISO-19770-2:2015.

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



      1.  Primary Tag - A SWID tag that identifies and describes a
          software component is installed on a computing device.

      2.  Patch Tag - A SWID tag that identifies and describes an
          installed patch which has made incremental changes to a
          software component installed on a computing device.

      3.  Corpus Tag - A SWID 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 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.

      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.













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  Installation     Product       Product      Product       Product
    Media      -> Installed  ->  Patched   -> Upgraded   -> Removed
   Deployed

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


      The figure above illustrates the steps in the software lifecycle
      and the relationships among those lifecycle events supported by
      the four types of SWID 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 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.





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   Each of the different SWID tag types of SWID tags provide different
   types of information.  For example, a "corpus tag" is used to
   describe an application's installation image on an installation
   media, while a "patch tag" is meant to describe a patch that modifies
   some other application.  While there are very few required fields in
   SWID tags, there are many optional fields that support different uses
   of these different types of tags.  While a SWID tag that consisted
   only of required fields could be a few hundred bytes in size, a tag
   containing many of the optional fields could be many orders of
   magnitude larger.

1.2.  Concise SWID Extensions

   This document defines a more concise representation of SWID tags in
   the Concise Binary Object Representation (CBOR) [RFC7049].  This is
   described via the Concise Data Definition Language (CDDL)
   [I-D.greevenbosch-appsawg-cbor-cddl].  The resulting Concise SWID
   data definition is interoperable 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, is mapped to
   more concise labels represented as small integers.  The names used in
   the CDDL data definition and the mapping to the CBOR representation
   using integer labels is based on the vocabulary of the XML attribute
   and element names defined in ISO/IEC 19770-2:2015.

   This document specifies a standardized equivalent to the ISO-
   19770-2:2015 standard.  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 the main body 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.  These are covered in
      appendices to this document.

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].






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2.  Concise SWID Data Definition

   The following is a CDDL representation of the ISO/IEC 19770-2:2015
   [SWID] XML schema definition of SWID tags.  This representation
   includes every SWID tag field and attribute and thus supports all
   SWID tag use cases.  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 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.

   Concise Software Identifiers are tailored to be used in the domain of
   constrained-node networks.  A typical endpoint is capable of storing
   the CoSWID tag of installed software, a constrained-node might lack
   that capability.  CoSWID address these constraints and the
   corresponding specification is augmented to retain their usefulness
   in the thing-2-thing domain.  Specific examples include, but are not
   limited to limiting the scope of hash algorithms to the IANA Named
   Information tables or including firmware attributes addressing
   devices that do not necessarily provide a file-system to store a
   CoSWID tag in.

   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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   <CODE BEGINS>
   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 ),
     ? any-element-entry,
   }
   tag-id = (0: text)
   swid-name = (1: text)
   entity-entry = (2: entity / [ 2* entity ])
   evidence-entry = (3: evidence)
   link-entry = (4: link / [ 2* link ])
   software-meta-entry = (5: software-meta / [ 2* software-meta ])
   payload-entry = (6: payload)
   any-element-entry = (7: any-element-map / [ 2* any-element-map ])
   corpus = (8: bool)
   patch = (9: bool)
   media = (10: text)
   supplemental = (11: bool)
   tag-version = (12: integer)
   software-version = (13: text)
   version-scheme = (14: text)
   <CODE ENDS>

   The items are ordered ensure that tag metadata appears first,
   followed by general software metadata, entity information, link
   relations, and finally payload or evidence data.  This ordering
   attempts to provide the most significant metadata that a parser may
   need first, followed by metadata that may support more specific use-
   applications.  The following describes each child item of the
   concise-software-identity 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.





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   o  tag-id (label 0): An textual identifier uniquely referencing a
      (composite) software component.  The tag identifier is intended to
      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).

   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.  A typical use of this
      field may be to set an initial value to 0 and to monotonically
      increase the value for subsequent tags produced for the specific
      release.  A change in the value of this field may be the case if a
      CoSWID tag producer creates and releases an incorrect tag that
      they subsequently want to fix, but with no underlying changes 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 is updated.

   o  corpus (label 8): A boolean value that indicates if the tag
      identifies and describes an installable software component in its
      pre-installation state.  Installable software includes a
      installation package or installer for a software component, a
      software update, or a patch.  If the Concise SWID 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 product.  If a Concise SWID 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 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 Concise SWID tag is a supplemntal 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".




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   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 SWID tag applies to.  This item can also be
      included in the link item to represent a attributes 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.

   o  software-meta-entry (label 5): An open-ended collection of key/
      value data related to this CoSWID.  The attributes included in
      this Element are predefined attributes to ensure common usage
      across the industry.  The schema allows for any additional
      attribute to be included in a CoSWID tag, 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): Specifies the organizations related to the
      software component referenced by this CoSWID tag.  Described in
      Section 2.4.

   o  link-entry (label 4): A reference to any another item (can include
      details that are related to the CoSWID tag such as details on
      where specific resources can be found, e.g.  vulnerability
      database associations, ROLIE feeds, MUD files, etc).  This is
      modeled directly to match the HTML "link" element; it is critical
      for streamlining software discovery scenarios to ensure their
      consistency.  Described in Section 2.5.

   o  payload-entry (label 6): The items that may be installed on a
      system entity when the software component is installed.  Note that
      payload may be a superset of the items installed and - depending
      on optimization mechanisms in respect to that system entity - may
      or may not include every item that could be created or executed on



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      the corresponding system entitiy when software components are
      installed.  In general, payload will be used to indicate the files
      that may be installed with a software component.  Therefore
      payload will often be a superset of those files (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.  This information is not provided by the
      software-creator, and is instead created when a system is being
      scanned and the evidence for why software is believed to be
      installed on the device is provided in the evidence item.
      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 be also
      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 Section 2.3.

2.1.1.  Determining the tag type

   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".

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

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

   If multiple of the corpus, patch, and supplemental items are "true",
   then the containing tag MUST be considered an unsupported tag type.

   If the patch does modify 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.








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2.1.2.  concise-software-identity Co-constraints

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

   o  If the patch item is set to "true", the 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 the tag SHOULD
      contain at least one link with the rel(ation) item value of
      "suplements" 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 ensure that primary and corpus tags have
      an identifiable software version.

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:

   <CODE BEGINS>
   global-attributes = (
     ? lang,
     * any-attribute,
   )

   label = text / int

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

   lang = (15: text)
   <CODE ENDS>

   The following describes each child item of this object.



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   o  lang (index 15): A language tag or corresponding IANA index
      integer 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 any-element-entry

   The CDDL for the any-element-entry object is as follows:

   <CODE BEGINS>
   any-element-map = {
     global-attributes,
     * label => any-element-map / [ 2* any-element-map ],
   }
   any-element-entry = (7: any-element-map / [ 2* any-element-map ])
   <CODE ENDS>

   The following describes each child item of this object.

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

   o  label: a single or multiple

2.4.  The entity Object

   The CDDL for the entity object is as follows:




















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   <CODE BEGINS>
   entity = {
     global-attributes,
     entity-name,
     ? reg-id,
     role,
     ? thumbprint,
     extended-data,
   }

   any-uri = text

   extended-data = (30: any-element-map / [ 2* any-element-map ])
   entity-name = (31: text)
   reg-id = (32: any-uri)
   role = (33: text / [2* text])
   thumbprint = (34: text)
   <CODE ENDS>

   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.) that
      is implied by the referenced naming authority.  The value of an
      registration ID MUST be a RFC 3986 URI.  The scope SHOULD be the
      scope of an 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 tag creator is required for every CoSWID
      tag.  The role of an entity may include any role value, but the
      per-defined roles include: "aggregator", "distributor",
      "licensor", "software-creator", "tag-creator".  The enumerations
      of this will include a request to IANA in order to be reference-
      able via an integer index.

   o  thumbprint (index 34): This value provides a hexadecimal string
      that contains a hash (i.e. the thumbprint) of the signing entities
      certificate(s). .





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   o  extended-data (index 30): An open-ended collection of elements
      that can be used to attach arbitrary metadata to an entity item.

2.5.  The link Object

   The CDDL for the link object is as follows:

   <CODE BEGINS>
   link = {
     global-attributes,
     ? artifact,
     href,
     ? media
     ? ownership,
     rel,
     ? media-type,
     ? use,
   }
   artifact = (37: text)
   href = (38: any-uri)
   media = (10: any-uri)
   ownership = (39: "shared" / "private" / "abandon")
   rel = (40: text)
   media-type = (41: text)
   use = (42: "optional" / "required" / "recommended")
   <CODE ENDS>

   The following describes each child item of this object.

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

   o  artifact (index: 37): For installation media (rel="installation-
      media") - dictates the canonical name for the file.  Items with
      the same artifact name should be considered mirrors of each other
      (so download from wherever works).

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

      *  a relative uri (no scheme), which is interpreted depending on
         context (for example, "./folder/supplemental.coswid")

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





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      *  an 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 system by software that can lookup other CoSWID
         tags (for example,

      *  "coswid:2df9de35-0aff-4a86-ace6-f7dddd1ade4c").  an 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 dedicated 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 was "Contoso".

      *  swidpath://SoftwareIdentity[Meta/@persistentId='b0c55172-38e9-4
         e36-be86-92206ad8eddb'] would retrieve CoSWID tags that matched
         the persistent-id.

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

   o  media (index 10): See media defined in Section 2.1.

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

   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 file;
      this provides the consumer with intelligence of what to expect.
      See http://www.iana.org/assignments/media-types/media-types.xhtml
      for more details on link type.

   o  use (index 42): Determines if the target software is a hard
      requirement or not.  Valid enumerations are: required,
      recommended, optional.

2.6.  The software-meta Object

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






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   <CODE BEGINS>

   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,
   }
   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)
   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)
   <CODE ENDS>

   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 a
      computing device.

   o  persistent-id (index 51): A GUID used to represent products
      installed where the product are related, but may be different
      versions.  For example, an "upgradeCode" (see
      http://msdn.microsoft.com/en-us/library/aa372375(v=vs.85).aspx as
      an reference for this example).

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

   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 devices.  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 will provide very exact version
      details, 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 the ID in the
   Named Information Hash Algorithm table; other hash algorithms MUST
   NOT be used.  The hash-value MUST represent the raw hash value of the
   hashed resource generated using the hash algorithm indicated by the
   hash-alg-id.



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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:

   <CODE BEGINS>
   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,
   )



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   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)
   type = (29: text)
   <CODE ENDS>

   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.

   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.



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   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.

   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
   }
   <CODE ENDS>

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

   o  $$payload-extension:

2.7.4.  The evidence Object

   The CDDL for the evidence object is as follows:

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

   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  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:

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.

   <CODE BEGINS>
   concise-software-identity = {



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     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 ),
     ? any-element-entry,
   }

   any-uri = text
   label = text / int

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

   any-element-map = {
     global-attributes,
     * label => any-element-map / [ 2* any-element-map ],
   }

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

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

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




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   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,
     extended-data,
   }

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

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



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     ? 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)
   link-entry = (4: link / [ 2* link ])
   software-meta-entry = (5: software-meta / [ 2* software-meta ])
   payload-entry = (6: payload)
   any-element-entry = (7: any-element-map / [ 2* any-element-map ])
   corpus = (8: bool)
   patch = (9: bool)
   media = (10: text)
   supplemental = (11: bool)
   tag-version = (12: integer)
   software-version = (13: text)
   version-scheme = (14: text / int)
   lang = (15: text)
   directory-entry = (16: directory / [ 2* directory ])
   file-entry = (17: file / [ 2* file ])
   process-entry = (18: process / [ 2* process ])



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   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)
   type = (29: text)
   extended-data = (30: any-element-map / [ 2* any-element-map ])
   entity-name = (31: text)
   reg-id = (32: any-uri)
   role = (33: text / [2* text])
   thumbprint = (34: text)
   date = (35: time)
   device-id = (36: text)
   artifact = (37: text)
   href = (38: any-uri)
   ownership = (39: "shared" / "private" / "abandon")
   rel = (40: text)
   media-type = (41: text)
   use = (42: "optional" / "required" / "recommended")
   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)
   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,
                    ]
               )
   <CODE ENDS>




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3.  CoSWID Indexed Label Values

3.1.  Version Scheme

   The following are 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.

   o  multipartnumeric (index 0): 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)

   o  multipartnumeric+suffix (index 1): Numbers separated by dots,
      where the numbers are interpreted as integers with an additional
      string suffix(e.g., 1.2.3a)

   o  alphanumeric (index 2): Strictly a string, sorting is done
      alphanumerically

   o  decimal (index 3): A floating point number (e.g., 1.25 is less
      than 1.3)

   o  semver (index 4): Follows the [SEMVER] specification

   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.

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                |
   |-------+--------------------------+
   | 0     | tagCreator               |
   | 1     | softwareCreator          |
   | 2     | aggregator               |
   | 3     | distributor              |
   | 4     | licensor                 |


   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 226 through 255 have been reserved for private use.




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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:

   | 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           | multipartnumeric         | See section 3.1 |
   | 1           | multipartnumeric+suffix  | See section 3.1 |
   | 2           | alphanumeric             | See section 3.1 |
   | 3           | decimal                  | See section 3.1 |
   | 4-16383     | Unassigned               |                 |
   | 16384       | semver                   | {{SEMVER}}      |
   | 16385-32767 | Unassigned               |                 |
   | 32768-65535 | Reserved for Private Use |                 |








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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:

   | 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       | tagCreator               | See section 3.2 |
   | 1       | softwareCreator          | See section 3.2 |
   | 2       | aggregator               | See section 3.2 |
   | 3       | distributor              | See section 3.2 |
   | 4       | licensor                 | See section 3.2 |
   | 5-49    | Unassigned               |                 |
   | 50-225  | Unassigned               |                 |
   | 225-255 | Reserved for Private Use |                 |


5.  Security Considerations

   SWID 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 is intact can be relied upon to be
   unchanged since it was signed.  If the SWID tag was created by the
   software author, this generally means that it has undergone no change
   since the software application with which the tag is associated was



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   installed.  By implication, this means that the signed tag reflects
   the software author's understanding of the details of that software
   product.  This can be useful assurance when the information in the
   tag needs to be trusted, such as when the tag is being used to convey
   golden measurements.  By contrast, the data contained in unsigned
   tags cannot be trusted to be unmodified.

   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 intend
   if creating non-deterministic states during validation or processing



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   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.

6.  Acknowledgments

7.  Change Log

   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




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

   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-12
              (work in progress), February 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>.

   [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 19770-5:2013,
              November 2013.

   [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.



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   [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.banghart-sacm-rolie-softwaredescriptor]
              Waltermire, D. and S. Banghart, "Definition of the ROLIE
              Software Descriptor Extension", draft-banghart-sacm-rolie-
              softwaredescriptor-01 (work in progress), May 2017.

   [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.greevenbosch-appsawg-cbor-cddl]
              Birkholz, H., Vigano, C., and C. Bormann, "Concise data
              definition language (CDDL): a notational convention to
              express CBOR data structures", draft-greevenbosch-appsawg-
              cbor-cddl-11 (work in progress), July 2017.

   [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-14 (work in progress), December 2017.

   [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>.

   [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)

   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



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




















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<CODE BEGINS>
$$payload-extension  //= (firmware-entry,)
$$evidence-extension  //= (firmware-entry,)

firmware = {
  firmware-name,                  ; inherited from RFC4108
  ? firmware-version,
  ? firmware-package-identifier,  ; inherited from RFC4108
  ? dependency,                   ; inherited from RFC4108
  ? component-index,              ; equivalent to RFC4108 fwPkgType
  ? block-device-identifier,
  ? target-hardware-identifier,   ; an RFC4108 alternative to model-label
  model-label,
  ? hash-entry,                   ; a hash for a single, incl. NI hash-algo index
  ? cms-firmware-package,         ; RCF4108, experimental, this is an actual firmware blob!
}

firmware-entry = (60: firmware / [ 2* firmware ])
firmware-name = (61 : text)
firmware-version = (62 : text / int)
component-index = (63 : int)
model-label = (64 text / int)
block-device-identifier = (65 : text / int)
cms-firmware-package = (66: bstr)
firmware-package-identifier = (67: text)
target-hardware-identifier = (68: text)
dependency = (69: { ? firmware-name,
                    ? firmware-version,
                    ? firmware-package-identifier,
                  }
             )
<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



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   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
   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.



























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<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>

Appendix C.  CoSWID used as Reference Integrity Measurements (CoSWID
             RIM)

   A vendor supplied signed CoSWID tag that includes hash-values for the
   files that compose a software component can be used as a RIM
   (reference integrity measurement).  A RIM is a type of declarative
   guidance that can be used to assert the compliance of an endpoint by
   assessing the installed software.  In the context of remote
   attestation based on an attestation via hardware rooted trust, a
   verifier can appraise the integrity of the conveyed measurements of
   software components using a CoSWID RIM provided by a source, such as
   [I-D.banghart-sacm-rolie-softwaredescriptor].

   RIM Manifests (RIMM):  A group of SWID tags about the same
      (sub-)system, system entity, or (sub-)component (compare
      [RFC4949]).  A RIMM manifest is a distinct document that is
      typically conveyed en-block and constitutes declarative guidance
      in respect to a specific (target) endpoint (compare
      [I-D.ietf-sacm-terminology]).

   If multiple CoSWID compose a RIMM, the following CDDL data definition
   SHOULD be used.




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   RIMM = [ + concise-software-identity / signed-coswid ]

Appendix D.  CBOR Web Token for Concise SWID Tags

   A typical requirement regarding specific instantiations of endpoints
   - and, as a result, specific instantiations of software components -
   is a representation of the absolute path of a CoSWID tag document in
   a file system in order to derive absolute paths of files represented
   in the corresponding CoSWID tag.  The absolute path of an evidence
   CoSWID tag can be included as a claim in the header of a CBOR Web
   Token [I-D.ietf-ace-cbor-web-token].  Depending on the source of the
   token, the claim can be in the protected or unprotected header
   portion.

   <CODE BEGINS>
    CDDL TBD
   <CODE ENDS>

Authors' Addresses

   Henk Birkholz
   Fraunhofer SIT
   Rheinstrasse 75
   Darmstadt  64295
   Germany

   Email: henk.birkholz@sit.fraunhofer.de


   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






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

   Email: david.waltermire@nist.gov












































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