Concise Software Identification Tags
draft-ietf-sacm-coswid-11

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SACM Working Group                                           H. Birkholz
Internet-Draft                                            Fraunhofer SIT
Intended status: Standards Track                     J. Fitzgerald-McKay
Expires: December 29, 2019                         Department of Defense
                                                              C. Schmidt
                                                   The MITRE Corporation
                                                           D. Waltermire
                                                                    NIST
                                                           June 27, 2019

                  Concise Software Identification Tags
                       draft-ietf-sacm-coswid-11

Abstract

   ISO/IEC 19770-2:2015 Software Identification (SWID) tags provide an
   extensible XML-based structure to identify and describe individual
   software components, patches, and installation bundles.  SWID tag
   representations can be too large for devices with network and storage
   constraints.  This document defines a concise representation of SWID
   tags: Concise SWID (CoSWID) tags.  CoSWID supports the same features
   as SWID tags, as well as additional semantics that allow CoSWIDs to
   describe additional types of information, all in a more memory
   efficient format.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on December 29, 2019.

Copyright Notice

   Copyright (c) 2019 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
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   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 and CoSWID Tag Lifecycle . . . . . . . . . . . .   4
     1.2.  Concise SWID Format . . . . . . . . . . . . . . . . . . .   6
     1.3.  Requirements Notation . . . . . . . . . . . . . . . . . .   7
   2.  Concise SWID Data Definition  . . . . . . . . . . . . . . . .   7
     2.1.  Concise SWID Extensions . . . . . . . . . . . . . . . . .   8
     2.2.  The concise-swid-tag Group  . . . . . . . . . . . . . . .  10
     2.3.  concise-swid-tag Co-constraints . . . . . . . . . . . . .  14
     2.4.  The global-attributes Group . . . . . . . . . . . . . . .  15
     2.5.  The entity-entry Group  . . . . . . . . . . . . . . . . .  16
     2.6.  The link-entry Map  . . . . . . . . . . . . . . . . . . .  18
     2.7.  The software-meta-entry Map . . . . . . . . . . . . . . .  22
     2.8.  The Resource Collection Definition  . . . . . . . . . . .  25
       2.8.1.  The hash-entry Array  . . . . . . . . . . . . . . . .  25
       2.8.2.  The resource-collection Group . . . . . . . . . . . .  25
       2.8.3.  The payload-entry Group . . . . . . . . . . . . . . .  29
       2.8.4.  The evidence-entry Group  . . . . . . . . . . . . . .  29
     2.9.  Full CDDL Definition  . . . . . . . . . . . . . . . . . .  30
   3.  Determining the Type of CoSWID  . . . . . . . . . . . . . . .  35
   4.  CoSWID Indexed Label Values . . . . . . . . . . . . . . . . .  36
     4.1.  Version Scheme  . . . . . . . . . . . . . . . . . . . . .  36
     4.2.  Entity Role Values  . . . . . . . . . . . . . . . . . . .  37
     4.3.  Link Ownership Values . . . . . . . . . . . . . . . . . .  38
     4.4.  Link Rel Values . . . . . . . . . . . . . . . . . . . . .  39
     4.5.  Link Use Values . . . . . . . . . . . . . . . . . . . . .  41
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  42
     5.1.  CoSWID Items Registry . . . . . . . . . . . . . . . . . .  42
     5.2.  SWID/CoSWID Value Registries  . . . . . . . . . . . . . .  45
       5.2.1.  SWID/CoSWID Version Scheme Value Registry . . . . . .  45
       5.2.2.  SWID/CoSWID Entity Role Value Registry  . . . . . . .  46
       5.2.3.  SWID/CoSWID Link Ownership Value Registry . . . . . .  48
       5.2.4.  SWID/CoSWID Link Relationship Value Registry  . . . .  49
       5.2.5.  SWID/CoSWID Link Use Value Registry . . . . . . . . .  52
     5.3.  swid+cbor Media Type Registration . . . . . . . . . . . .  53
     5.4.  CoAP Content-Format Registration  . . . . . . . . . . . .  54
     5.5.  CBOR Tag Registration . . . . . . . . . . . . . . . . . .  54

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   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  55
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  56
   8.  Change Log  . . . . . . . . . . . . . . . . . . . . . . . . .  56
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  60
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  60
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  60
     10.2.  Informative References . . . . . . . . . . . . . . . . .  62
   Appendix A.  Signed Concise SWID Tags using COSE  . . . . . . . .  63
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  64

1.  Introduction

   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 software, a patch, or an installation bundle,
   which are referred to as software components in this document.
   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.

   SWID tags are used to support a number of processes 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-rats-tuda].

   While there are very few required fields in SWID tags, there are many
   optional fields that support different uses.  A SWID tag consisting
   of only required fields might be a few hundred bytes in size;
   however, 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 usage
   scenarios, 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 items to more

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   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.

1.1.  The SWID and CoSWID 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 SWID specification and supporting guidance provided in NIST
   Internal Report (NISTIR) 8060: Guidelines for the Creation of
   Interoperable SWID Tags [SWID-GUIDANCE] defines four types of SWID
   tags: primary, patch, corpus, and supplemental.  The following text
   is paraphrased from these sources.

   1.  Primary Tag - A SWID or CoSWID tag that identifies and describes
       an installed software component on an endpoint.  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 that 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
       allows tools and users to record their own metadata about a
       software component without modifying SWID primary or patch tags
       created by a software provider.

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   The type of a tag is determined by specific data elements, which are
   discussed in Section 3.

      Corpus, primary, and patch tags have similar functions in that
      they describe the existence and/or presence of different types of
      software components (e.g., software installers, software
      installations, software patches), and, potentially, different
      states of these software components.  Supplemental tags have the
      same structure as other tags, but are used to provide information
      not contained in the referenced corpus, primary, and 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            |
   Software      Software        Software     Software      Software
   Deployment -> Installation -> Patching  -> Upgrading  -> Removal

   Corpus        Primary         Primary      xPrimary      xPrimary
   Supplemental  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 can also be installed during software
         installation to provide information about software fixes
         deployed along with the base software installation.

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      *  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.

   As 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.

   Understanding the use of CoSWIDs in the software lifecycle provides a
   basis for understanding the information provided in a CoSWID and the
   associated semantics of this information.  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 Format

   This document defines the CoSWID tag format, which is based on the
   Concise Binary Object Representation (CBOR) [RFC7049].  CBOR-based
   CoSWID tags offer a more concise representation of SWID information
   as compared to the XML-based SWID tag representation in ISO-
   19770-2:2015.  The structure of a CoSWID is described via the Concise
   Data Definition Language (CDDL) [RFC8610].  The resulting CoSWID data
   definition is aligned to the information able to be expressed with
   the XML schema definition of ISO-19770-2:2015 [SWID].  This alignment
   allows both SWID and CoSWID tags to represent a common set of
   software component information and allows CoSWID tags to support the
   same uses as a SWID tag.  To achieve this end, the CDDL
   representation includes every SWID tag field and attribute.

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

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
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  Concise SWID Data Definition

   The following describes the general rules and processes for encoding
   data using CDDL representation.  Prior familiarity with CBOR and CDDL
   concepts will be helpful in understanding this CoSWID data
   definition.

   This section describes the rules by which SWID tag XML is represented
   in the CoSWID CDDL structure.  The CamelCase [CamelCase] notation
   used in the XML schema definition is changed to a hyphen-separated
   notation [KebabCase] (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 to by its name in CamelCase
   notation explicitly relates to XML SWID tags; an attribute referred
   to by its name in KebabCase notation explicitly relates to CBOR
   CoSWID tags.  This approach simplifies the composition of further
   work that reference both XML SWID and CBOR CoSWID documents.

   Note that sometimes CoSWID CDDL attribute names show greater
   variation than the described notation change relative to their
   corresponding SWID XML Schema attributes.  This is done when the
   change improves clarity in the specification.  For example the "name"
   and "version" SWID fields corresponds to the "software-name" and
   "software-version" CoSWID fields, respectively.  As such, it is not
   always possible to mechanically translate between corresponding
   attribute names in the two formats.

   The 57 human-readable text labels of the CDDL-based CoSWID vocabulary
   are mapped to integer indices via a block of rules at the bottom of
   the definition.  This allows a more concise integer-based form to be

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   stored or transported, as compared to the less efficient text-based
   form of the original vocabulary.

   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 rule above allows either a single data item or an array of 2
   or more data values to be provided.  When a singleton data value is
   provided, the CBOR markers for the array, array length, and stop
   point are not needed saving bytes.  When two or more data values are
   provided, these values are encoded as an array.  This modeling
   pattern is used frequently in the CoSWID CDDL data definition to
   allow for more efficient encoding of singleton values.

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

2.1.  Concise SWID Extensions

   The CoSWID data definition contains two features that are not
   included in the SWID data definition on which it is based.  These
   features are:

   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 2.4.

   o  The inclusion of extension points in the CoSWID data definition
      using CDDL sockets (see [RFC8610] section 3.9).  The use of CDDL
      sockets allow for well-formed extensions to be defined in
      supplementary CDDL descriptions that support additional uses of
      CoSWID tags that go beyond the original scope of ISO-19770-2:2015
      tags.  This extension mechanism can also be used to update the
      CoSWID format as revisions to ISO-19770-2 are published.

   The following CDDL sockets (extension points) are defined in this
   document, which allow the addition of new information structures to
   their respective CDDL groups.

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      +---------------------+-----------------------+---------------+
      | Map Name            | CDDL Socket           | Defined in    |
      +---------------------+-----------------------+---------------+
      | concise-swid-tag    | $$coswid-extension    | Section 2.2   |
      |                     |                       |               |
      | entity-entry        | $$entity-extension    | Section 2.5   |
      |                     |                       |               |
      | link-entry          | $$link-extension      | Section 2.6   |
      |                     |                       |               |
      | software-meta-entry | $$meta-extension      | Section 2.7   |
      |                     |                       |               |
      | file-entry          | $$file-extension      | Section 2.8.2 |
      |                     |                       |               |
      | directory-entry     | $$directory-extension | Section 2.8.2 |
      |                     |                       |               |
      | process-entry       | $$process-extension   | Section 2.8.2 |
      |                     |                       |               |
      | resource-entry      | $$resource-extension  | Section 2.8.2 |
      |                     |                       |               |
      | payload-entry       | $$payload-extension   | Section 2.8.3 |
      |                     |                       |               |
      | evidence-entry      | $$evidence-extension  | Section 2.8.4 |
      +---------------------+-----------------------+---------------+

                Table 1: CoSWID CDDL Group Extension Points

   The CoSWID Items Registry defined in Section 5.1 provides a
   registration mechanism allowing new items, and their associated index
   values, to be added to the CoSWID model through the use of the CDDL
   sockets described in the table above.  This registration mechanism
   provides for well-known index values for data items in CoSWID
   extensions, allowing these index values to be recognized by
   implementations supporting a given extension.

   The following additional CDDL sockets are defined in this document to
   allow for adding new values to corresponding type-choices (i.e. to
   represent enumerations) via custom CDDL data definitions.

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           +------------------+-----------------+-------------+
           | Enumeration Name | CDDL Socket     | Defined in  |
           +------------------+-----------------+-------------+
           | version-scheme   | $version-scheme | Section 4.1 |
           |                  |                 |             |
           | role             | $role           | Section 4.2 |
           |                  |                 |             |
           | ownership        | $ownership      | Section 4.3 |
           |                  |                 |             |
           | rel              | $rel            | Section 4.4 |
           |                  |                 |             |
           | use              | $use            | Section 4.5 |
           +------------------+-----------------+-------------+

             Table 2: CoSWID CDDL Enumeration Extension Points

   A number of SWID/CoSWID value registries are also defined in
   Section 5.2 that allow new values to be registered with IANA for the
   enumerations above.  This registration mechanism supports the
   definition of new well-known index values and names for new
   enumeration values used by both SWID and CoSWID.  This registration
   mechanism allows new standardized enumerated values to be shared
   between both specifications (and implementations) over time, and
   references to the IANA registries will be added to the next revision
   of [SWID].

2.2.  The concise-swid-tag Group

   The CDDL data definition for the root concise-swid-tag map is as
   follows and this rule and its constraints MUST be followed when
   creating or validating a CoSWID tag:

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 concise-swid-tag = {
   global-attributes,
   tag-id => text,
   tag-version => integer,
   ? corpus => bool,
   ? patch => bool,
   ? supplemental => bool,
   software-name => text,
   ? software-version => text,
   ? version-scheme => $version-scheme,
   ? media => text,
   ? software-meta =>  software-meta-entry / [ 2* software-meta-entry ],
   entity => entity-entry / [ 2* entity-entry ],
   ? link => link-entry / [ 2* link-entry ],
   ? (( payload => payload-entry ) // ( evidence => evidence-entry )),
   * $$coswid-extension
 }

 tag-id = 0
 software-name = 1
 entity = 2
 evidence = 3
 link = 4
 software-meta = 5
 payload = 6
 corpus = 8
 patch = 9
 media = 10
 supplemental = 11
 tag-version = 12
 software-version = 13
 version-scheme = 14

 $version-scheme /= multipartnumeric
 $version-scheme /= multipartnumeric-suffix
 $version-scheme /= alphanumeric
 $version-scheme /= decimal
 $version-scheme /= semver
 $version-scheme /= uint / text
 multipartnumeric = 1
 multipartnumeric-suffix = 2
 alphanumeric = 3
 decimal = 4
 semver = 16384

   The following describes each member of the concise-swid-tag root map.

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   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 2.4.

   o  tag-id (index 0): A textual identifier uniquely referencing a
      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 (index 12): An integer value that indicate the
      specific release revision of the tag.  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 value allows a CoSWID tag producer to
      correct an incorrect tag previously released without indicating a
      change to the underlying software component the tag represents.
      For example, the tag version could be changed to add new metadata,
      to correct a broken link, to add a missing payload entry, etc.
      When producing a revised tag, the new tag-version value MUST be
      greater than the old tag-version value.

   o  corpus (index 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 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 (index 9): A boolean value that indicates if the tag
      identifies and describes an installed patch that has made
      incremental changes to a software component installed on an
      endpoint.  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, the patch
      item MUST be set to "true".  If not provided, the default value
      MUST be considered "false".

      Note: If the software component's version number is modified, then
      the correct course of action would be to replace the previous
      primary tag for the component with a new primary tag that
      reflected this new version.  In such a case, the new tag would
      have a patch item value of "false" or would omit this item
      completely.

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   o  supplemental (index 11): A boolean value that indicates if the tag
      is providing additional information to be associated with another
      referenced SWID or CoSWID tag.  This allows tools and users to
      record their own metadata about a software component without
      modifying SWID primary or patch tags created by a software
      provider.  If a CoSWID tag is a supplemental tag, the supplemental
      item MUST be set to "true".  If not provided, the default value
      MUST be considered "false".

   o  software-name (index 1): This textual item provides the software
      component's name.  This name is likely the same name that would
      appear in a package management tool.

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

   o  version-scheme (index 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
      SWID/CoSWID Version Scheme Value Registry (see section
      Section 5.2.1 or a value in the private use range: 32768-65535.

   An initial set of version-scheme index and text values are defined in
   Section 4.1, and are based on the version-scheme values defined in
   [SWID].  These pre-defined version-scheme values are registered with
   IANA in the "SWID/CoSWID Version Scheme Value" registry
   Section 5.2.1.  The values in this registry will likely be expanded
   in the future.

   The value of an version-scheme item MUST be one of the following:

   o  The index (preferred) or string value of a role from the IANA in
      the "SWID/CoSWID Version Scheme Value" registry.

   o  An index value in the range 32768 through 65535, to indicate that
      a private use index value is used.

   o  A string value prefixed with "x_", to indicate that a private use
      string value is used.

   o  media (index 10): This text value is a hint to the tag consumer to
      understand what target platform this tag applies to.  This item
      represents a query as defined by the W3C Media Queries
      Recommendation (see [W3C.REC-css3-mediaqueries-20120619]).

   o  software-meta (index 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.  Use

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      of this map allows any additional attribute to be included in the
      tag.  It is expected that industry groups will use a common set of
      attribute names to allow for interoperability within their
      communities.  Described in Section 2.7.

   o  entity (index 2): Provides information about one or more
      organizations responsible for producing the CoSWID tag, and
      producing or releasing the software component referenced by this
      CoSWID tag.  Described in Section 2.5.

   o  link (index 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 [RFC8322], MUD resource
      [RFC8520], software download location, etc).  This is modeled
      after the HTML "link" element.  Described in Section 2.6.

   o  payload (index 6): This item represents a collection of software
      artifacts (described by child items) that compose the target
      software.  For example, these artifacts could be the files
      included with an installer for a corpus tag or installed on an
      endpoint when the software component is installed for a primary or
      patch tag.  The artifacts listed in a payload may be a superset of
      the software artifacts that are actually installed.  Based on user
      selections at install time, an installation might not include
      every artifact that could be created or executed on the endpoint
      when the software component is installed or run.  Described in
      Section 2.8.3.

   o  evidence-entry (index 3): This item can be used to record the
      results of a software discovery process used to identify untagged
      software on an endpoint or to represent indicators for why
      software is believed to be installed on the endpoint.  In either
      case, a CoSWID tag can be created by the tool performing an
      analysis of the software components installed on the endpoint.
      Described in Section 2.8.4.

   o  $$coswid-extension: This CDDL socket is used to add new
      information structures to the concise-swid-tag root map.  See
      Section 2.1.

2.3.  concise-swid-tag Co-constraints

   The following co-constraints apply to the information provided in the
   concise-swid-tag group.

   o  The patch and supplemental items MUST NOT both be set to "true".

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   o  If the patch item is set to "true", the tag SHOULD contain at
      least one link item with both 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 item with both 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.

2.4.  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 follows:

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

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

   label = text / int

   The following describes each child item of this group.

   o  lang (index 15): A textual language tag that conforms with IANA
      "Language Subtag Registry" [RFC5646].  The context of the
      specified language applies to all sibling and descendant textual
      values, unless a descendant object has defined a different
      language tag.  Thus, a new context is established when a
      descendant object redefines a new language tag.  All textual
      values within a given context MUST be considered expressed in the
      specified language.

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

2.5.  The entity-entry Group

   The CDDL for the entity-entry group follows:

   entity-entry = {
     global-attributes,
     entity-name => text,
     ? reg-id => any-uri,
     role => $role / [ 2* $role ],
     ? thumbprint => hash-entry,
     * $$entity-extension,
   }
   entity-name = 31
   reg-id = 32
   role = 33
   thumbprint = 34

   $role /= tag-creator
   $role /= software-creator
   $role /= aggregator
   $role /= distributor
   $role /= licensor
   $role /= uint / text
   tag-creator=1
   software-creator=2
   aggregator=3
   distributor=4
   licensor=5

   The following describes each child item of this group.

   o  global-attributes: The global-attributes group described in
      Section 2.4.

   o  entity-name (index 32): The textual name of the organizational
      entity claiming the roles specified by the role item for the
      CoSWID tag.

   o  reg-id (index 32): The registration id value is intended to
      uniquely identify a naming authority in a given scope (e.g.
      global, organization, vendor, customer, administrative domain,
      etc.) for the referenced entity.  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 for CoSWID tag production.

   o  role (index 33): The relationship(s) between the entity, and this
      tag or the referenced software component.  Use of index values
      instead of text for these pre-defined roles allows a CoSWID to be
      more concise.

      An initial set of role index and text values are defined in
      Section 4.2, and are based on the roles defined in [SWID].  These
      pre-defined roles are registered with IANA in the "SWID/CoSWID
      Entity Role Value" registry Section 5.2.2.  The values in this
      registry will likely be expanded in the future.

      The value of a role item MUST be one of the following:

      *  The index (preferred) or string value of a role from the IANA
         in the "SWID/CoSWID Entity Role Value" registry.

      *  An index value in the range 128 through 255, to indicate that a
         private use index value is used.

      *  A string value prefixed with "x_", to indicate that a private
         use string value is used.

      The following additional requirements exist for the use of the
      "role" item:

      *  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.

      *  An entity item SHOULD be provided with the role of "software-
         creator" for every CoSWID tag, if this information is known to
         the tag creator.  This indicates the organization that created
         the referenced software component.

   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 entity's public
      key certificate.  This provides an indicator of which entity
      signed the CoSWID tag, which will typically be the tag creator.
      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 2.8.1 for more details on the use of the
      hash-entry data structure.

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   o  $$entity-extension: This CDDL socket can be used to extend the
      entity-entry group model.  See Section 2.1.

2.6.  The link-entry Map

   The CDDL for the link-entry map follows:

   link-entry = {
     global-attributes,
     ? artifact => text,
     href => any-uri,
     ? media => text,
     ? ownership => $ownership,
     rel => $rel,
     ? media-type => text,
     ? use => $use,
     * $$link-extension,
   }
   media = 10
   artifact = 37
   href = 38
   ownership = 39
   rel = 40
   media-type = 41
   use = 42

   $ownership /= shared
   $ownership /= private
   $ownership /= abandon
   $ownership /= uint / text
   shared=1
   private=2
   abandon=3

   $rel /= ancestor
   $rel /= component
   $rel /= feature
   $rel /= installationmedia
   $rel /= packageinstaller
   $rel /= parent
   $rel /= patches
   $rel /= requires
   $rel /= see-also
   $rel /= supersedes
   $rel /= supplemental
   $rel /= uint / text
   ancestor=1
   component=2

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   feature=3
   installationmedia=4
   packageinstaller=5
   parent=6
   patches=7
   requires=8
   see-also=9
   supersedes=10
   supplemental=11

   $use /= optional
   $use /= required
   $use /= recommended
   $use /= uint / text
   optional=1
   required=2
   recommended=3

   The following describes each member of this map.

   o  global-attributes: The global-attributes group described in
      Section 2.4.

   o  artifact (index: 37): To be used with rel="installation-media",
      this item's value provides the path to the installer executable or
      script that can be run to launch the referenced installation.
      Links with the same artifact name MUST be considered mirrors of
      each other, allowing the installation media to be acquired from
      any of the described sources.

   o  href (index 38): A URI for the referenced resource.  The "href"
      item's value can be, but is not limited to, the following (which
      is a slightly modified excerpt from [SWID]):

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

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      *  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 [W3C.REC-xpath20-20101214].

         Examples include:

         +  swidpath://SoftwareIdentity[Entity/@regid='http://contoso.co
            m'] would retrieve all SWID or CoSWID tags that include an
            entity where the regid is "Contoso"

         +  swidpath://SoftwareIdentity[Meta/@persistentId='b0c55172-38e
            9-4e36-be86-92206ad8eddb'] would match all SWID or CoSWID
            tags with the persistent-id value
            "b0c55172-38e9-4e36-be86-92206ad8eddb"

   o  media (index 10): A hint to the consumer of the link to what
      target platform the link is applicable to.  This item represents a
      query as defined by the W3C Media Queries Recommendation (see
      [W3C.REC-css3-mediaqueries-20120619]).  See also media defined in
      Section 2.2.

   o  ownership (index 39): Used when the "href" item references another
      software component to indicate the degree of ownership between the
      software component referenced by the COSWID tag and the software
      component referenced by the link.

      An initial set of ownership index and text values are defined in
      Section 4.3, and are based on the ownership values defined in
      [SWID].  These pre-defined ownership values are registered with
      IANA in the "SWID/CoSWID Link Ownership Value" registry
      Section 5.2.3.  The values in this registry will likely be
      expanded in the future.

      The value of an ownership item MUST be one of the following:

      *  The index (preferred) or string value of a role from the IANA
         in the "SWID/CoSWID Link Ownership Value" registry.

      *  An index value in the range 128 through 255, to indicate that a
         private use index value is used.

      *  A string value prefixed with "x_", to indicate that a private
         use string value is used.

   o  rel (index 40): Identifies the relationship between this CoSWID
      and the target resource indicated by the "href" item.

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      An initial set of rel index and text values are defined in
      Section 4.4, and are based on the rel values defined in [SWID].
      These pre-defined rel values are registered with IANA in the
      "SWID/CoSWID Link Relationship Value" registry Section 5.2.4.  The
      values in this registry will likely be expanded in the future.

      The value of a rel item MUST be one of the following:

      *  The index (preferred) or string value of a role from the IANA
         in the "SWID/CoSWID Link Relationship Value" registry.

      *  An index value in the range 128 through 255, to indicate that a
         private use index value is used.

      *  A string value prefixed with "x_", to indicate that a private
         use string value is used.

      *  A string value, as defined by [RFC8288], corresponding to a
         "Relation Name" from the IANA "Link Relation Types" registry:
         https://www.iana.org/assignments/link-relations/link-
         relations.xhtml.  When a string value defined in the IANA
         "SWID/CoSWID Link Relationship Value" registry matches a
         Relation Name defined in the IANA "Link Relation Types"
         registry, the value in the IANA "SWID/CoSWID Link Relationship
         Value" registry MUST be used instead, as this relationship has
         a specialized meaning in the context of a SWID/CoSWID tag.

   o  media-type (index 41): A link can point to arbitrary resources on
      the endpoint, local network, or Internet using the href item.  Use
      of this item supplies the resource consumer with a hint of what
      type of resource to expect.  Media types are identified by
      referencing a "Name" from the IANA "Media Types" registry:
      http://www.iana.org/assignments/media-types/media-types.xhtml.

   o  use (index 42): Determines if the referenced software component
      has to be installed before installing the software component
      identified by the tag.

      An initial set of use index and text values are defined in
      Section 4.5, and are based on the use values defined in [SWID].
      These pre-defined use values are registered with IANA in the
      "SWID/CoSWID Link Use Value" registry Section 5.2.5.  The values
      in this registry will likely be expanded in the future.

      The value of an ownership item MUST be one of the following:

      *  The index (preferred) or string value of a role from the IANA
         in the "SWID/CoSWID Link Use Value" registry.

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      *  An index value in the range 128 through 255, to indicate that a
         private use index value is used.

      *  A string value prefixed with "x_", to indicate that a private
         use string value is used.

   o  $$link-extension: This CDDL socket can be used to extend the link-
      entry map model.  See Section 2.1.

2.7.  The software-meta-entry Map

   The CDDL for the software-meta-entry map follows:

   software-meta-entry = {
     global-attributes,
     ? activation-status => text,
     ? channel-type => text,
     ? colloquial-version => text,
     ? description => text,
     ? edition => text,
     ? entitlement-data-required => bool,
     ? entitlement-key => text,
     ? generator => text,
     ? persistent-id => text,
     ? product => text,
     ? product-family => text,
     ? revision => text,
     ? summary => text,
     ? unspsc-code => text,
     ? unspsc-version => text,
     * $$meta-extension,
   }
   activation-status = 43
   channel-type = 44
   colloquial-version = 45
   description = 46
   edition = 47
   entitlement-data-required = 48
   entitlement-key = 49
   generator = 50
   persistent-id = 51
   product = 52
   product-family = 53
   revision = 54
   summary = 55
   unspsc-code = 56
   unspsc-version = 57

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   The following describes each child item of this group.

   o  global-attributes: The global-attributes group described in
      Section 2.4.

   o  activation-status (index 43): A textual value that identifies how
      the software component has been activated, which might relate to
      specific terms and conditions for its use (e.g.  Trial,
      Serialized, Licensed, Unlicensed, etc) and relate to an
      entitlement.  This attribute is typically used in supplemental
      tags as it contains information that might be selected during a
      specific install.

   o  channel-type (index 44): A textual value that identfies which
      sales, licensing, or marketing channel the software component has
      been targeted for (e.g.  Volume, Retail, OEM, Academic, etc).
      This attribute is typically used in supplemental tags as it
      contains information that might be selected during a specific
      install.

   o  colloquial-version (index 45): A textual value for the software
      component's informal or colloquial version.  Examples may include
      a year value, a major version number, or similar value that are
      used to identify a group of specific software component releases
      that are part of the same release/support cycle.  This version can
      be the same through multiple releases of a software component,
      while the software-version specified in the concise-swid-tag group
      is much more specific and will change for each software component
      release.  This version is intended to be used for string
      comparison only and is not intended to be used to determine if a
      specific value is earlier or later in a sequence.

   o  description (index 46): A textual value that provides a detailed
      description of the software component.  This value MAY be multiple
      sentences.

   o  edition (index 47): A textual value indicating that the software
      component represents a functional variation of the code base used
      to support multiple software components.  For examplem, this item
      can be used to differentiate enterprise, standard, or professional
      variants of a software component.

   o  entitlement-data-required (index 48): A boolean value that can be
      used to determine if accompanying proof of entitlement is needed
      when a software license reconciliation process is performed.

   o  entitlement-key (index 49): A vendor-specific textual key that can
      be used to identify and establish a relationship to an

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      entitlement.  Examples of an entitlement-key might include a
      serial number, product key, or license key.  For values that
      relate to a given software component install (i.e., license key),
      a supplemental tag will typically contain this information.  In
      other cases, where a general-purpose key can be provided that
      applies to all possible installs of the software component on
      different endpoints, a primary tag will typically contain this
      information.

   o  generator (index 50): The name (or tag-id) of the software
      component that created the CoSWID tag.  If the generating software
      component has a SWID or CoSWID tag, then the tag-id for the
      generating software component SHOULD be provided.

   o  persistent-id (index 51): A globally unique identifier used to
      identify a set of software components that are related.  Software
      components sharing the same persistent-id can be different
      versions.  This item can be used to relate software components,
      released at different points in time or through different release
      channels, that may not be able to be related through use of the
      link item.

   o  product (index 52): A basic name for the software component that
      can be common across multiple tagged software components (e.g.,
      Apache HTTPD).

   o  product-family (index 53): A textual value indicating the software
      components overall product family.  This should be used when
      multiple related software components form a larger capability that
      is installed on multiple different endpoints.  For example, some
      software families may consist of server, client, and shared
      service components that are part of a larger capability.  Email
      systems, enterprise applications, backup services, web
      conferencing, and similar capabilities are examples of families.
      Use of this item is not intended to represent groups of software
      that are bundled or installed together.  The persistent-id or link
      items SHOULD be used to relate bundled software components.

   o  revision (index 54): A string value indicating an informal or
      colloquial release version of the software.  This value can
      provide a different version value as compared to the software-
      version specified in the concise-swid-tag group.  This is useful
      when one or more releases need to have an informal version label
      that differs from the specific exact version value specified by
      software-version.  Examples can include SP1, RC1, Beta, etc.

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   o  summary (index 55): A short description of the software component.
      This MUST be a single sentence suitable for display in a user
      interface.

   o  unspsc-code (index 56): An 8 digit UNSPSC classification code for
      the software component.  For more information see,
      http://www.unspsc.org/.

   o  unspsc-version (index 57): The version of UNSPSC used to define
      the unspsc-code value.

   o  $$meta-extension: This CDDL socket can be used to extend the
      software-meta-entry group model.  See Section 2.1.

2.8.  The Resource Collection Definition

2.8.1.  The hash-entry Array

   CoSWID adds explicit support for the representation of hash entries
   using algorithms that are registered in the IANA "Named Information
   Hash Algorithm Registry" using the hash-entry member (label 58).

   hash-entry = [ hash-alg-id: int, hash-value: bytes ]

   The number used as a value for hash-alg-id MUST refer an ID in the
   "Named Information Hash Algorithm Registry" (see
   https://www.iana.org/assignments/named-information/named-
   information.xhtml); 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.

2.8.2.  The resource-collection Group

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

   The CDDL for the resource-collection group follows:

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

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

   path-elements-entry = [ [ * file-entry ],
                           [ * directory-entry ],
                         ]

   file-entry = {
     filesystem-item,
     ? size => integer,
     ? file-version => text,
     ? hash => hash-entry,
     * $$file-extension
   }

   directory-entry = {
     filesystem-item,
     path-elements => path-elements-entry,
     * $$directory-extension
   }

   process-entry = {
     global-attributes,
     process-name => text,
     ? pid => integer,
     * $$process-extension
   }

   resource-entry = {
     global-attributes,
     type => text,
     * $$resource-extension
   }

   directory = 16
   file = 17
   process = 18
   resource = 19
   size = 20
   file-version = 21
   key = 22
   location = 23
   fs-name = 24

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   root = 25
   path-elements = 26
   process-name = 27
   pid = 28
   type = 29

   The following describes each member of the groups and maps
   illustrated above.

   o  filesystem-item: A list of common items used for representing the
      filesystem root, relative location, name, and significance of a
      file or directory item.

   o  global-attributes: The global-attributes group described in
      Section 2.4.

   o  directory (index 16): A directory item allows child directory and
      file items to be defined within a directory hierarchy for the
      software component.

   o  file (index 17): A file item allows details about a file to be
      provided for the software component.

   o  process (index 18): A process item allows details to be provided
      about the runtime behavior of the software component, such as
      information that will appear in a process listing on an endpoint.

   o  resource (index 19): A resource item can be used to provide
      details about an artifact or capability expected to be found on an
      endpoint or evidence collected related to the software component.
      This can be used to represent concepts not addressed directly by
      the directory, file, or process items.  Examples include: registry
      keys, bound ports, etc.  The equivalent construct in [SWID] is
      currently under specified.  As a result, this item might be
      further defined through extension in the future.

   o  size (index 20): The file's size in bytes.

   o  file-version (index 21): The file's version as reported by
      querying information on the file from the operating system.

   o  key (index 22): A boolean value indicating if a file or directory
      is significant or required for the software component to execute
      or function properly.  These are files or directories that can be
      used to affirmatively determine if the software component is
      installed on an endpoint.

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   o  location (index 23): The filesystem path where a file is expected
      to be located when installed or copied.  The location MUST be
      either relative to the location of the parent directory item
      (preferred) or relative to the location of the CoSWID tag if no
      parent is defined.  The location MUST NOT include a file's name,
      which is provided by the fs-name item.

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

   o  root (index 25): A filesystem-specific name for the root of the
      filesystem.  The location item is considered relative to this
      location if specified.  If not provided, the value provided by the
      location item is expected to be relative to its parent or the
      location of the CoSWID tag if no parent is provided.

   o  path-elements (index 26): This group allows a heirarchy of
      directory and file items to be defined in payload or evidence
      items.

   o  process-name (index 27): The software component's process name as
      it will appear in an endpoint's process list.

   o  pid (index 28): The process ID identified for a running instance
      of the software component in the endpoint's process list.  This is
      used as part of the evidence item.

   o  type (index 29): A string indicating the type of resource.

   o  $$resource-collection-extension: This CDDL socket can be used to
      extend the resource-collection group model.  This can be used to
      add new specialized types of resources.  See Section 2.1.

   o  $$file-extension: This CDDL socket can be used to extend the file-
      entry group model.  See Section 2.1.

   o  $$directory-extension: This CDDL socket can be used to extend the
      directory-entry group model.  See Section 2.1.

   o  $$process-extension: This CDDL socket can be used to extend the
      process-entry group model.  See Section 2.1.

   o  $$resource-extension: This CDDL socket can be used to extend the
      group model.  See Section 2.1.

   o  $$-extension: This CDDL socket can be used to extend the resource-
      entry group model.  See Section 2.1.

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2.8.3.  The payload-entry Group

   The CDDL for the payload-entry group follows:

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

   The following describes each child item of this group.

   o  global-attributes: The global-attributes group described in
      Section 2.4.

   o  resource-collection: The resource-collection group described in
      Section 2.8.2.

   o  $$payload-extension: This CDDL socket can be used to extend the
      payload-entry group model.  See Section 2.1.

2.8.4.  The evidence-entry Group

   The CDDL for the evidence-entry group follows:

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

   The following describes each child item of this group.

   o  global-attributes: The global-attributes group described in
      Section 2.4.

   o  resource-collection: The resource-collection group described in
      Section 2.8.2.

   o  date (index 35): The date and time the information was collected
      pertaining to the evidence item.

   o  device-id (index 36): The endpoint's string identifier from which
      the evidence was collected.

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   o  $$evidence-extension: This CDDL socket can be used to extend the
      evidence-entry group model.  See Section 2.1.

2.9.  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-swid-tag = {
   global-attributes,
   tag-id => text,
   tag-version => integer,
   ? corpus => bool,
   ? patch => bool,
   ? supplemental => bool,
   software-name => text,
   ? software-version => text,
   ? version-scheme => $version-scheme,
   ? media => text,
   ? software-meta =>  software-meta-entry / [ 2* software-meta-entry ],
   entity => entity-entry / [ 2* entity-entry ],
   ? link => link-entry / [ 2* link-entry ],
   ? (( payload => payload-entry ) // ( evidence => evidence-entry )),
   * $$coswid-extension
 }

 any-uri = text
 label = text / int

 $version-scheme /= multipartnumeric
 $version-scheme /= multipartnumeric-suffix
 $version-scheme /= alphanumeric
 $version-scheme /= decimal
 $version-scheme /= semver
 $version-scheme /= uint / text

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

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

 hash-entry = [ hash-alg-id: int,
                hash-value: bytes ]

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 entity-entry = {
   global-attributes,
   entity-name => text,
   ? reg-id => any-uri,
   role => $role / [ 2* $role ],
   ? thumbprint => hash-entry,
   * $$entity-extension,
 }

 $role /= tag-creator
 $role /= software-creator
 $role /= aggregator
 $role /= distributor
 $role /= licensor
 $role /= uint / text

 link-entry = {
   global-attributes,
   ? artifact => text,
   href => any-uri,
   ? media => text,
   ? ownership => $ownership,
   rel => $rel,
   ? media-type => text,
   ? use => $use,
   * $$link-extension
 }

 $ownership /= shared
 $ownership /= private
 $ownership /= abandon
 $ownership /= uint / text

 $rel /= ancestor
 $rel /= component
 $rel /= feature
 $rel /= installationmedia
 $rel /= packageinstaller
 $rel /= parent
 $rel /= patches
 $rel /= requires
 $rel /= see-also
 $rel /= supersedes
 $rel /= supplemental
 $rel /= uint / text

 $use /= optional
 $use /= required

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 $use /= recommended
 $use /= uint / text

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

 resource-collection = (
   ? directory => directory-entry,
   ? file => file-entry,
   ? process => process-entry,
   ? resource => resource-entry,
   * $$resource-collection-extension
 )

 file-entry = {
   filesystem-item,
   ? size => integer,
   ? file-version => text,
   ? hash => hash-entry,
   * $$file-extension
 }

 path-elements-entry = [ [ * file-entry ],
                         [ * directory-entry ],
                       ]

 directory-entry = {
   filesystem-item,
   path-elements => path-elements-entry,
   * $$directory-extension
 }

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 process-entry = {
   global-attributes,
   process-name => text,
   ? pid => integer,
   * $$process-extension
 }

 resource-entry = {
   global-attributes,
   type => text,
   * $$resource-extension
 }

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

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

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

 ; "global map member" integer indexes
 tag-id = 0
 software-name = 1
 entity = 2
 evidence = 3
 link = 4
 software-meta = 5
 payload = 6
 hash = 7
 corpus = 8
 patch = 9
 media = 10
 supplemental = 11

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 tag-version = 12
 software-version = 13
 version-scheme = 14
 lang = 15
 directory = 16
 file = 17
 process = 18
 resource = 19
 size = 20
 file-version = 21
 key = 22
 location = 23
 fs-name = 24
 root = 25
 path-elements = 26
 process-name = 27
 pid = 28
 type = 29
 entity-name = 31
 reg-id = 32
 role = 33
 thumbprint = 34
 date = 35
 device-id = 36
 artifact = 37
 href = 38
 ownership = 39
 rel = 40
 media-type = 41
 use = 42
 activation-status = 43
 channel-type = 44
 colloquial-version = 45
 description = 46
 edition = 47
 entitlement-data-required = 48
 entitlement-key = 49
 generator = 50
 persistent-id = 51
 product = 52
 product-family = 53
 revision = 54
 summary = 55
 unspsc-code = 56
 unspsc-version = 57

 ; "version-scheme" integer indexes
 multipartnumeric = 1

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 multipartnumeric-suffix = 2
 alphanumeric = 3
 decimal = 4
 semver = 16384

 ; "role" integer indexes
 tag-creator=1
 software-creator=2
 aggregator=3
 distributor=4
 licensor=5

 ; ownership integer indexes
 shared=1
 private=2
 abandon=3

 ; "rel" integer indexes
 ancestor=1
 component=2
 feature=3
 installationmedia=4
 packageinstaller=5
 parent=6
 patches=7
 requires=8
 see-also=9
 supersedes=10
 supplemental=11

 ; "use" integer indexes
 optional=1
 required=2
 recommended=3

3.  Determining the Type of CoSWID

   The operational model for SWID and CoSWID tags was introduced in
   Section 1.1, which described four different CoSWID tag types.  The
   following additional rules apply to the use of CoSWID tags to ensure
   that created tags properly identify the tag type.

   The first matching rule MUST determine the type of the CoSWID tag.

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

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

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

   4.  Patch Tag: A CoSWID tag MUST be considered a patch tag if the
       patch item is "true".

   Note: Multiple of the corpus, patch, and supplemental items can have
   values set as "true".  The rules above provide a means to determine
   the tag's type in such a case.  For example, a SWID or CoSWID tag for
   a patch installer might have both corpus and patch items set to
   "true".  In such a case, the tag is a "Corpus Tag".  The tag
   installed by this installer would have only the patch item set to
   "true", making the installed tag type a "Patch Tag".

4.  CoSWID Indexed Label Values

4.1.  Version Scheme

   The following table contains a set of values for use in the concise-
   swid-tag group's version-scheme item.  These values match the version
   schemes defined in the ISO/IEC 19770-2:2015 [SWID] specification.
   Index value indicates the value to use as the version-scheme item's
   value.  The Version Scheme Name provides human-readable text for the
   value.  The Definition describes the syntax of allowed values for
   each entry.

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   +-------+-------------------------+---------------------------------+
   | Index | Version Scheme Name     | Definition                      |
   +-------+-------------------------+---------------------------------+
   | 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 textual 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                   |
   +-------+-------------------------+---------------------------------+

                      Table 3: Version Scheme Values

   The values above are registered in the IANA "SWID/CoSWID Version
   Scheme Value" registry defined in section Section 5.2.1.  Additional
   values will likely be registered over time in this registry.
   Additionally, the index values 32768 through 65535 and the name
   prefix "x_" have been reserved for private use.

4.2.  Entity Role Values

   The following table indicates the index value to use for the entity-
   entry group's role item (see Section 2.5).  These values match the
   entity roles defined in the ISO/IEC 19770-2:2015 [SWID]
   specification.  The "Index" value indicates the value to use as the
   role item's value.  The "Role Name" provides human-readable text for
   the value.  The "Definition" describes the semantic meaning of each
   entry.

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   +-------+-----------------+-----------------------------------------+
   | Index | Role Name       | Definition                              |
   +-------+-----------------+-----------------------------------------+
   | 1     | tagCreator      | The person or organization that created |
   |       |                 | the containing SWID or CoSWID tag       |
   |       |                 |                                         |
   | 2     | softwareCreator | The person or organization entity that  |
   |       |                 | created the software component.         |
   |       |                 |                                         |
   | 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", a    |
   |       |                 | "person or organization who owns or     |
   |       |                 | holds the rights to issue a software    |
   |       |                 | license for a specific software         |
   |       |                 | [component]"                            |
   +-------+-----------------+-----------------------------------------+

                        Table 4: Entity Role Values

   The values above are registered in the IANA "SWID/CoSWID Entity Role
   Value" registry defined in section Section 5.2.2.  Additional values
   will likely be registered over time.  Additionally, the index values
   128 through 255 and the name prefix "x_" have been reserved for
   private use.

4.3.  Link Ownership Values

   The following table indicates the index value to use for the link-
   entry group's ownership item (see Section 2.6).  These values match
   the link ownership values defined in the ISO/IEC 19770-2:2015 [SWID]
   specification.  The "Index" value indicates the value to use as the
   link-entry group ownership item's value.  The "Ownership Type"

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   provides human-readable text for the value.  The "Definition"
   describes the semantic meaning of each entry.

   +-------+-----------+-----------------------------------------------+
   | Index | Ownership | Definition                                    |
   |       | Type      |                                               |
   +-------+-----------+-----------------------------------------------+
   | 1     | abandon   | If the software component referenced by the   |
   |       |           | CoSWID tag is uninstalled, then the           |
   |       |           | referenced software SHOULD not be uninstalled |
   |       |           |                                               |
   | 2     | private   | If the software component referenced by the   |
   |       |           | CoSWID tag is uninstalled, then the           |
   |       |           | referenced software SHOULD be uninstalled as  |
   |       |           | well.                                         |
   |       |           |                                               |
   | 3     | shared    | If the software component referenced by the   |
   |       |           | CoSWID tag is uninstalled, then the           |
   |       |           | referenced software SHOULD be uninstalled if  |
   |       |           | no other components sharing the software.     |
   +-------+-----------+-----------------------------------------------+

                      Table 5: Link Ownership Values

   The values above are registered in the IANA "SWID/CoSWID Link
   Ownership Value" registry defined in section Section 5.2.3.
   Additional values will likely be registered over time.  Additionally,
   the index values 128 through 255 and the name prefix "x_" have been
   reserved for private use.

4.4.  Link Rel Values

   The following table indicates the index value to use for the link-
   entry group's rel item (see Section 2.6).  These values match the
   link rel values defined in the ISO/IEC 19770-2:2015 [SWID]
   specification.  The "Index" value indicates the value to use as the
   link-entry group ownership item's value.  The "Relationship Type"
   provides human-readable text for the value.  The "Definition"
   describes the semantic meaning of each entry.

   +-------+-------------------+---------------------------------------+
   | Index | Relationship Type | Definition                            |
   +-------+-------------------+---------------------------------------+
   | 1     | ancestor          | The link references a SWID/CoSWID tag |
   |       |                   | for a previous release of this        |
   |       |                   | software. This can be useful to       |
   |       |                   | define an upgrade path.               |
   |       |                   |                                       |

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   | 2     | component         | The link references a SWID/CoSWID tag |
   |       |                   | for a separate component of this      |
   |       |                   | software.                             |
   |       |                   |                                       |
   | 3     | feature           | The link references a configurable    |
   |       |                   | feature of this software that can be  |
   |       |                   | enabled or disabled without changing  |
   |       |                   | the installed files.                  |
   |       |                   |                                       |
   | 4     | installationmedia | The link references the installation  |
   |       |                   | package that can be used to install   |
   |       |                   | this software.                        |
   |       |                   |                                       |
   | 5     | packageinstaller  | The link references the installation  |
   |       |                   | software needed to install this       |
   |       |                   | software.                             |
   |       |                   |                                       |
   | 6     | parent            | The link references a SWID/CoSWID tag |
   |       |                   | that is the parent of this            |
   |       |                   | SWID/CoSWID tag. This relationship    |
   |       |                   | can be used when multiple software    |
   |       |                   | components are part of a software     |
   |       |                   | bundle, where the "parent" is the     |
   |       |                   | SWID/CoSWID tag for the bundle, and   |
   |       |                   | each child is a "component". In such  |
   |       |                   | a case, each child component can      |
   |       |                   | provide a "parent" link relationship  |
   |       |                   | to the bundle's SWID/CoSWID tag, and  |
   |       |                   | the bundle can provide a "component"  |
   |       |                   | link relationship to each child       |
   |       |                   | software component.                   |
   |       |                   |                                       |
   | 7     | patches           | The link references a SWID/CoSWID tag |
   |       |                   | that this software patches. Typically |
   |       |                   | only used for patch SWID/CoSWID tags  |
   |       |                   | (see Section 1.1).                    |
   |       |                   |                                       |
   | 8     | requires          | The link references a prerequisite    |
   |       |                   | for installing this software. A patch |
   |       |                   | SWID/CoSWID tag (see Section 1.1) can |
   |       |                   | use this to represent base software   |
   |       |                   | or another patch that needs to be     |
   |       |                   | installed first.                      |
   |       |                   |                                       |
   | 9     | see-also          | The link references other software    |
   |       |                   | that may be of interest that relates  |
   |       |                   | to this software.                     |
   |       |                   |                                       |

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   | 10    | supersedes        | The link references another software  |
   |       |                   | that this software replaces. A patch  |
   |       |                   | SWID/CoSWID tag (see Section 1.1) can |
   |       |                   | use this to represent another patch   |
   |       |                   | that this patch incorporates or       |
   |       |                   | replaces.                             |
   |       |                   |                                       |
   | 11    | supplemental      | The link references a SWID/CoSWID tag |
   |       |                   | that this tag supplements. Used on    |
   |       |                   | supplemental SWID/CoSWID tags (see    |
   |       |                   | Section 1.1).                         |
   +-------+-------------------+---------------------------------------+

                     Table 6: Link Relationship Values

   The values above are registered in the IANA "SWID/CoSWID Link
   Relationship Value" registry defined in section Section 5.2.4.
   Additional values will likely be registered over time.  Additionally,
   the index values 32768 through 65535 and the name prefix "x_" have
   been reserved for private use.

4.5.  Link Use Values

   The following table indicates the index value to use for the link-
   entry group's use item (see Section 2.6).  These values match the
   link use values defined in the ISO/IEC 19770-2:2015 [SWID]
   specification.  The "Index" value indicates the value to use as the
   link-entry group use item's value.  The "Use Type" provides human-
   readable text for the value.  The "Definition" describes the semantic
   meaning of each entry.

   +-------+-------------+---------------------------------------------+
   | Index | Use Type    | Definition                                  |
   +-------+-------------+---------------------------------------------+
   | 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."                       |
   +-------+-------------+---------------------------------------------+

                         Table 7: Link Use Values

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   The values above are registered in the IANA "SWID/CoSWID Link Use
   Value" registry defined in section Section 5.2.5.  Additional values
   will likely be registered over time.  Additionally, the index values
   128 through 255 and the name prefix "x_" have been reserved for
   private use.

5.  IANA Considerations

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

5.1.  CoSWID Items Registry

   This document uses integer values as index values in CBOR maps.

   This document defines a new a new registry titled "CoSWID Items".
   Future registrations for this registry are to be made based on
   [RFC8126] as follows:

              +------------------+-------------------------+
              | Range            | Registration Procedures |
              +------------------+-------------------------+
              | 0-32767          | Standards Action        |
              |                  |                         |
              | 32768-4294967295 | Specification Required  |
              +------------------+-------------------------+

              Table 8: CoSWID Items Registration Proceedures

   All negative values are reserved for Private Use.

   Initial registrations for the "CoSWID Items" registry are provided
   below.  Assignments consist of an integer index value, the item name,
   and a reference to the defining specification.

       +---------------+---------------------------+---------------+
       | Index         | Item Name                 | Specification |
       +---------------+---------------------------+---------------+
       | 0             | tag-id                    | RFC-AAAA      |
       |               |                           |               |
       | 1             | software-name             | RFC-AAAA      |
       |               |                           |               |
       | 2             | entity                    | RFC-AAAA      |
       |               |                           |               |
       | 3             | evidence                  | RFC-AAAA      |
       |               |                           |               |
       | 4             | link                      | RFC-AAAA      |
       |               |                           |               |

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       | 5             | software-meta             | RFC-AAAA      |
       |               |                           |               |
       | 6             | payload                   | RFC-AAAA      |
       |               |                           |               |
       | 7             | hash                      | RFC-AAAA      |
       |               |                           |               |
       | 8             | corpus                    | RFC-AAAA      |
       |               |                           |               |
       | 9             | patch                     | RFC-AAAA      |
       |               |                           |               |
       | 10            | media                     | RFC-AAAA      |
       |               |                           |               |
       | 11            | supplemental              | RFC-AAAA      |
       |               |                           |               |
       | 12            | tag-version               | RFC-AAAA      |
       |               |                           |               |
       | 13            | software-version          | RFC-AAAA      |
       |               |                           |               |
       | 14            | version-scheme            | RFC-AAAA      |
       |               |                           |               |
       | 15            | lang                      | RFC-AAAA      |
       |               |                           |               |
       | 16            | directory                 | RFC-AAAA      |
       |               |                           |               |
       | 17            | file                      | RFC-AAAA      |
       |               |                           |               |
       | 18            | process                   | RFC-AAAA      |
       |               |                           |               |
       | 19            | resource                  | RFC-AAAA      |
       |               |                           |               |
       | 20            | size                      | RFC-AAAA      |
       |               |                           |               |
       | 21            | file-version              | RFC-AAAA      |
       |               |                           |               |
       | 22            | key                       | RFC-AAAA      |
       |               |                           |               |
       | 23            | location                  | RFC-AAAA      |
       |               |                           |               |
       | 24            | fs-name                   | RFC-AAAA      |
       |               |                           |               |
       | 25            | root                      | RFC-AAAA      |
       |               |                           |               |
       | 26            | path-elements             | RFC-AAAA      |
       |               |                           |               |
       | 27            | process-name              | RFC-AAAA      |
       |               |                           |               |
       | 28            | pid                       | RFC-AAAA      |
       |               |                           |               |

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       | 29            | type                      | RFC-AAAA      |
       |               |                           |               |
       | 31            | entity-name               | RFC-AAAA      |
       |               |                           |               |
       | 32            | reg-id                    | RFC-AAAA      |
       |               |                           |               |
       | 33            | role                      | RFC-AAAA      |
       |               |                           |               |
       | 34            | thumbprint                | RFC-AAAA      |
       |               |                           |               |
       | 35            | date                      | RFC-AAAA      |
       |               |                           |               |
       | 36            | device-id                 | RFC-AAAA      |
       |               |                           |               |
       | 37            | artifact                  | RFC-AAAA      |
       |               |                           |               |
       | 38            | href                      | RFC-AAAA      |
       |               |                           |               |
       | 39            | ownership                 | RFC-AAAA      |
       |               |                           |               |
       | 40            | rel                       | RFC-AAAA      |
       |               |                           |               |
       | 41            | media-type                | RFC-AAAA      |
       |               |                           |               |
       | 42            | use                       | RFC-AAAA      |
       |               |                           |               |
       | 43            | activation-status         | RFC-AAAA      |
       |               |                           |               |
       | 44            | channel-type              | RFC-AAAA      |
       |               |                           |               |
       | 45            | colloquial-version        | RFC-AAAA      |
       |               |                           |               |
       | 46            | description               | RFC-AAAA      |
       |               |                           |               |
       | 47            | edition                   | RFC-AAAA      |
       |               |                           |               |
       | 48            | entitlement-data-required | RFC-AAAA      |
       |               |                           |               |
       | 49            | entitlement-key           | RFC-AAAA      |
       |               |                           |               |
       | 50            | generator                 | RFC-AAAA      |
       |               |                           |               |
       | 51            | persistent-id             | RFC-AAAA      |
       |               |                           |               |
       | 52            | product                   | RFC-AAAA      |
       |               |                           |               |
       | 53            | product-family            | RFC-AAAA      |
       |               |                           |               |

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       | 54            | revision                  | RFC-AAAA      |
       |               |                           |               |
       | 55            | summary                   | RFC-AAAA      |
       |               |                           |               |
       | 56            | unspsc-code               | RFC-AAAA      |
       |               |                           |               |
       | 57            | unspsc-version            | RFC-AAAA      |
       |               |                           |               |
       | 58-4294967295 | Unassigned                |               |
       +---------------+---------------------------+---------------+

                Table 9: CoSWID Items Inital Registrations

5.2.  SWID/CoSWID Value Registries

   The following IANA registries provide a mechanism for new values to
   be added over time to common enumerations used by SWID and CoSWID.

5.2.1.  SWID/CoSWID Version Scheme Value Registry

   This document uses unsigned 16-bit index values to represent 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 titled "SWID/CoSWID
   Version Scheme Values".  Future registrations for this registry are
   to be made based on [RFC8126] as follows:

   [TO BE REMOVED: This registration should take place at the following
   location: https://www.iana.org/assignments/swid]

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

         Table 10: CoSWID Version Scheme Registration Proceedures

   Initial registrations for the "SWID/CoSWID Version Scheme Value"
   registry are provided below.  Assignments consist of an integer Index
   value, the Version Scheme Name, and a reference to the defining
   specification.

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       +-------------+--------------------------+-----------------+
       | Index       | Version Scheme Name      | Specification   |
       +-------------+--------------------------+-----------------+
       | 0           | Reserved                 |                 |
       |             |                          |                 |
       | 1           | multipartnumeric         | See Section 4.1 |
       |             |                          |                 |
       | 2           | multipartnumeric+suffix  | See Section 4.1 |
       |             |                          |                 |
       | 3           | alphanumeric             | See Section 4.1 |
       |             |                          |                 |
       | 4           | decimal                  | See Section 4.1 |
       |             |                          |                 |
       | 5-16383     | Unassigned               |                 |
       |             |                          |                 |
       | 16384       | semver                   | [SEMVER]        |
       |             |                          |                 |
       | 16385-32767 | Unassigned               |                 |
       |             |                          |                 |
       | 32768-65535 | Reserved for Private Use |                 |
       +-------------+--------------------------+-----------------+

           Table 11: CoSWID Version Scheme Inital Registrations

   Additional syntax requirements for registrations:

   o  All registered names MUST be valid according to the XML Schema
      NMTOKEN data type (see [W3C.REC-xmlschema-2-20041028] section
      3.3.4).

   o  The name prefix "x_" has been reserved for private use and NUST
      NOT be used in a registered name.

5.2.2.  SWID/CoSWID Entity Role Value Registry

   This document uses unsigned 8-bit index values to represent entity-
   entry role item 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 titled "SWID/CoSWID Entity
   Role Values".  Future registrations for this registry are to be made
   based on [RFC8126] as follows:

   [TO BE REMOVED: This registration should take place at the following
   location: https://www.iana.org/assignments/swid]

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

           Table 12: CoSWID Entity Role Registration Proceedures

   Initial registrations for the "SWID/CoSWID Entity Role Value"
   registry are provided below.  Assignments consist of an integer Index
   value, a Role Name, and a reference to the defining specification.

         +---------+--------------------------+-----------------+
         | Index   | Role Name                | Specification   |
         +---------+--------------------------+-----------------+
         | 0       | Reserved                 |                 |
         |         |                          |                 |
         | 1       | tagCreator               | See Section 4.2 |
         |         |                          |                 |
         | 2       | softwareCreator          | See Section 4.2 |
         |         |                          |                 |
         | 3       | aggregator               | See Section 4.2 |
         |         |                          |                 |
         | 4       | distributor              | See Section 4.2 |
         |         |                          |                 |
         | 5       | licensor                 | See Section 4.2 |
         |         |                          |                 |
         | 6-127   | Unassigned               |                 |
         |         |                          |                 |
         | 128-255 | Reserved for Private Use |                 |
         +---------+--------------------------+-----------------+

             Table 13: CoSWID Entity Role Inital Registrations

   Additional syntax requirements for registrations:

   o  All registered names MUST be valid according to the XML Schema
      NMTOKEN data type (see [W3C.REC-xmlschema-2-20041028] section
      3.3.4).

   o  The name prefix "x_" has been reserved for private use and NUST
      NOT be used in a registered name.

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5.2.3.  SWID/CoSWID Link Ownership Value Registry

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

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

   [TO BE REMOVED: This registration should take place at the following
   location: https://www.iana.org/assignments/swid]

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

         Table 14: CoSWID Link Ownership Registration Proceedures

   Initial registrations for the "SWID/CoSWID Link Ownership Value"
   registry are provided below.  Assignments consist of an integer Index
   value, an Ownership Type Name, and a reference to the defining
   specification.

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       +-------------+--------------------------+-----------------+
       | Index       | Ownership Type Name      | Definition      |
       +-------------+--------------------------+-----------------+
       | 0           | Reserved                 |                 |
       |             |                          |                 |
       | 1           | abandon                  | See Section 4.3 |
       |             |                          |                 |
       | 2           | private                  | See Section 4.3 |
       |             |                          |                 |
       | 3           | shared                   | See Section 4.3 |
       |             |                          |                 |
       | 4-16384     | Unassigned               |                 |
       |             |                          |                 |
       | 16385-32767 | Unassigned               |                 |
       |             |                          |                 |
       | 32768-65535 | Reserved for Private Use |                 |
       +-------------+--------------------------+-----------------+

           Table 15: CoSWID Link Ownership Inital Registrations

   Additional syntax requirements for registrations:

   o  All registered names MUST be valid according to the XML Schema
      NMTOKEN data type (see [W3C.REC-xmlschema-2-20041028] section
      3.3.4).

   o  The name prefix "x_" has been reserved for private use and NUST
      NOT be used in a registered name.

5.2.4.  SWID/CoSWID Link Relationship Value Registry

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

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

   [TO BE REMOVED: This registration should take place at the following
   location: https://www.iana.org/assignments/swid]

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

        Table 16: CoSWID Link Relationship Registration Proceedures

   Initial registrations for the "SWID/CoSWID Link Relationship Value"
   registry are provided below.  Assignments consist of an integer Index
   value, the Relationship Type Name, and a reference to the defining
   specification.

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       +-------------+--------------------------+-----------------+
       | Index       | Relationship Type Name   | Specification   |
       +-------------+--------------------------+-----------------+
       | 0           | Reserved                 |                 |
       |             |                          |                 |
       | 1           | ancestor                 | See Section 4.4 |
       |             |                          |                 |
       | 2           | component                | See Section 4.4 |
       |             |                          |                 |
       | 3           | feature                  | See Section 4.4 |
       |             |                          |                 |
       | 4           | installationmedia        | See Section 4.4 |
       |             |                          |                 |
       | 5           | packageinstaller         | See Section 4.4 |
       |             |                          |                 |
       | 6           | parent                   | See Section 4.4 |
       |             |                          |                 |
       | 7           | patches                  | See Section 4.4 |
       |             |                          |                 |
       | 8           | requires                 | See Section 4.4 |
       |             |                          |                 |
       | 9           | see-also                 | See Section 4.4 |
       |             |                          |                 |
       | 10          | supersedes               | See Section 4.4 |
       |             |                          |                 |
       | 11          | supplemental             | See Section 4.4 |
       |             |                          |                 |
       | 12-16384    | Unassigned               |                 |
       |             |                          |                 |
       | 16385-32767 | Unassigned               |                 |
       |             |                          |                 |
       | 32768-65535 | Reserved for Private Use |                 |
       +-------------+--------------------------+-----------------+

          Table 17: CoSWID Link Relationship Inital Registrations

   Additional syntax requirements for registrations:

   o  All registered names MUST be valid according to the XML Schema
      NMTOKEN data type (see [W3C.REC-xmlschema-2-20041028] section
      3.3.4).

   o  The name prefix "x_" has been reserved for private use and NUST
      NOT be used in a registered name.

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5.2.5.  SWID/CoSWID Link Use Value Registry

   This document uses unsigned 8-bit index values to represent link-
   entry use item 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 titled "SWID/CoSWID Link
   Use Values".  Future registrations for this registry are to be made
   based on [RFC8126] as follows:

   [TO BE REMOVED: This registration should take place at the following
   location: https://www.iana.org/assignments/swid]

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

            Table 18: CoSWID Link Use Registration Proceedures

   Initial registrations for the "SWID/CoSWID Entity Role Value"
   registry are provided below.  Assignments consist of an integer Index
   value, the Link Use Type Name, and a reference to the defining
   specification.

         +---------+--------------------------+-----------------+
         | Index   | Link Use Type Name       | Specification   |
         +---------+--------------------------+-----------------+
         | 0       | Reserved                 |                 |
         |         |                          |                 |
         | 1       | optional                 | See Section 4.5 |
         |         |                          |                 |
         | 2       | required                 | See Section 4.5 |
         |         |                          |                 |
         | 3       | recommended              | See Section 4.5 |
         |         |                          |                 |
         | 4-127   | Unassigned               |                 |
         |         |                          |                 |
         | 128-255 | Reserved for Private Use |                 |
         +---------+--------------------------+-----------------+

              Table 19: CoSWID Link Use Inital Registrations

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   Additional syntax requirements for registrations:

   o  All registered names MUST be valid according to the XML Schema
      NMTOKEN data type (see [W3C.REC-xmlschema-2-20041028] section
      3.3.4).

   o  The name prefix "x_" has been reserved for private use and NUST
      NOT be used in a registered name.

5.3.  swid+cbor Media Type Registration

   IANA is requested to add the following to the IANA "Media Types"
   registry.

   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 6 of RFC-AAAA.

   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-7049 section 7.5.

   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

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   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

5.4.  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]:

          +-----------------------+----------+------+-----------+
          | Media type            | Encoding | ID   | Reference |
          +-----------------------+----------+------+-----------+
          | application/swid+cbor | -        | TBD1 | RFC-AAAA  |
          +-----------------------+----------+------+-----------+

                     Table 20: CoAP Content-Format IDs

5.5.  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]                                |
   +------------+----------+-------------------------------------------+

                         Table 21: CoSWID CBOR Tag

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6.  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/CoSWID 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/
   CoSWID tags focus on the application of SWID/CoSWID tags to address
   security challenges, and the possible disclosure of the results of
   those applications.

   A signed SWID/CoSWID tag whose signature has been validated can be
   relied upon to be unchanged since it was signed.  If the SWID/CoSWID
   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/CoSWID tag contains information about a software
   component provided by the maintainer of the software component, who
   is expected to be an expert in their own software.  Thus,
   authoritative SWID/CoSWID tags can be trusted to represent
   authoritative information about the software component.  Having an
   authoritative SWID/CoSWID 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.

   SWID/CoSWID 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/CoSWID tags can be
   easier to add or remove.  On such systems, it can be possible to add
   or remove SWID/CoSWID 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/CoSWID tags, so
   products can be present on an endpoint without providing a
   corresponding SWID tag.  As such, any collection of SWID/CoSWID tags
   cannot automatically be assumed to represent either a complete or
   fully accurate representation of the software inventory of the
   endpoint.  However, especially on endpoint devices that more strictly
   control the ability to add or remove applications, SWID/CoSWID tags
   are an easy way to provide an preliminary understanding of that
   endpoint's software inventory.

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   Any report of an endpoint's SWID/CoSWID 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/CoSWID 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.  For this reason, it is important to protect the
   confidentiality of SWID/CoSWID tag information that has been
   collected from an endpoint, not because those tags individually
   contain sensitive information, but because the collection of SWID/
   CoSWID tags and their association with an endpoint reveals
   information about that endpoint's attack surface.

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

7.  Acknowledgments

   TBD

8.  Change Log

   Changes from version 03 to version 11:

   o  Reduced representation complexity of the media-entry type and
      removed the section describing the older data structure.

   o  Added more signature schemes from COSE

   o  Included a minimal required set of normative language

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   o  Reordering of attribute name to integer label by priority
      according to semantics.

   o  Added an IANA registry for CoSWID items supporting future
      extension.

   o  Cleaned up IANA registrations, fixing some inconsistencies in the
      table labels.

   o  Added additional CDDL sockets for resource collection entries
      providing for additional extension points to address future SWID/
      CoSWID extensions.

   o  Updated section on extension points to address new CDDL sockets
      and to reference the new IANA registry for items.

   o  Removed unused references and added new references to address
      placeholder comments.

   o  Added table with semantics for the link ownership item.

   o  Clarified language, made term use more consistent, fixed
      references, and replacing lowercase RFC2119 keywords.

   Changes from version 02 to version 03:

   o  Updated core CDDL including the CDDL design pattern according to
      RFC 8428.

   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

   Changes from version 00 to version 01:

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   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 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 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

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   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.

   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.

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   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

9.  Contributors

10.  References

10.1.  Normative References

   [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>.

   [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>.

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   [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>.

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

   [RFC8288]  Nottingham, M., "Web Linking", RFC 8288,
              DOI 10.17487/RFC8288, October 2017,
              <https://www.rfc-editor.org/info/rfc8288>.

   [RFC8610]  Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
              Definition Language (CDDL): A Notational Convention to
              Express Concise Binary Object Representation (CBOR) and
              JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
              June 2019, <https://www.rfc-editor.org/info/rfc8610>.

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

   [W3C.REC-css3-mediaqueries-20120619]
              Rivoal, F., "Media Queries", World Wide Web Consortium
              Recommendation REC-css3-mediaqueries-20120619, June 2012,
              <http://www.w3.org/TR/2012/
              REC-css3-mediaqueries-20120619>.

   [W3C.REC-xmlschema-2-20041028]
              Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes
              Second Edition", World Wide Web Consortium Recommendation
              REC-xmlschema-2-20041028, October 2004,
              <http://www.w3.org/TR/2004/REC-xmlschema-2-20041028>.

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   [W3C.REC-xpath20-20101214]
              Berglund, A., Boag, S., Chamberlin, D., Fernandez, M.,
              Kay, M., Robie, J., and J. Simeon, "XML Path Language
              (XPath) 2.0 (Second Edition)", World Wide Web Consortium
              Recommendation REC-xpath20-20101214, December 2010,
              <http://www.w3.org/TR/2010/REC-xpath20-20101214>.

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

10.2.  Informative References

   [CamelCase]
              "UpperCamelCase", August 2014,
              <http://wiki.c2.com/?CamelCase>.

   [I-D.birkholz-rats-tuda]
              Fuchs, A., Birkholz, H., McDonald, I., and C. Bormann,
              "Time-Based Uni-Directional Attestation", draft-birkholz-
              rats-tuda-00 (work in progress), March 2019.

   [KebabCase]
              "KebabCase", December 2014,
              <http://wiki.c2.com/?KebabCase>.

   [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>.

   [RFC8322]  Field, J., Banghart, S., and D. Waltermire, "Resource-
              Oriented Lightweight Information Exchange (ROLIE)",
              RFC 8322, DOI 10.17487/RFC8322, February 2018,
              <https://www.rfc-editor.org/info/rfc8322>.

   [RFC8520]  Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
              Description Specification", RFC 8520,
              DOI 10.17487/RFC8520, March 2019,
              <https://www.rfc-editor.org/info/rfc8520>.

   [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>.

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Appendix A.  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 tags.

   <CODE BEGINS>
   signed-coswid = #6.18(COSE-Sign1-coswid)

   cose-label = int / tstr
   cose-values = any

   protected-signed-coswid-header = {
       1 => int,                      ; algorithm identifier
       3 => "application/swid+cbor",
       * cose-label => cose-values,
   }

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

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

   Optionally, the COSE_Sign structure that allows for more than one
   signature to be applied to a CoSWID tag MAY be used.  The
   corresponding usage scenarios are domain-specific and require well-

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   defined application guidance.  Representation of the corresponding
   guidance is out-of-scope of this document.

   Additionally, the COSE Header counter signature MAY be used as an
   attribute in the unprotected header map of the COSE envelope of a
   CoSWID.  The application of counter signing enables second parties to
   provide a signature on a signature allowing for a proof that a
   signature existed at a given time (i.e., a timestamp).

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

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

   Email: david.waltermire@nist.gov

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