Fraunhofer SIT

Rheinstrasse 75 Darmstadt 64295 Germany henk.birkholz@sit.fraunhofer.de

National Security Agency

9800 Savage Road Ft. Meade Maryland USA jmfitz2@cyber.nsa.gov

The MITRE Corporation

202 Burlington Road Bedford Massachusetts 01730 USA cmschmidt@mitre.org

National Institute of Standards and Technology

100 Bureau Drive Gaithersburg Maryland 20877 USA david.waltermire@nist.gov

Security SACM Working Group Internet-Draft 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 a similar set of semantics and features as SWID tags, as well as new semantics that allow CoSWIDs to describe additional types of information, all in a more memory efficient format.

Introduction SWID tags, as defined in ISO-19770-2:2015 , 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:

• Software Inventory Management, a part of a Software Asset Management process, which requires an accurate list of discernible deployed software components.
• Vulnerability Assessment, which requires a semantic link between standardized vulnerability descriptions and software components installed on IT-assets .
• Remote Attestation, which requires a link between reference integrity measurements (RIM) and Attester-produced event logs that complement attestation evidence .

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 through the use of the Concise Binary Object Representation (CBOR) . Size comparisons between XML SWID and CoSWID mainly depend on domain-specific applications and the complexity of attributes used in instances. While the values stored in CoSWID are often unchanged and therefore not reduced in size compared to an XML SWID, the scaffolding that the CoSWID encoding represents is significantly smaller by taking up 10 percent or less in size. This effect is visible in representation sizes, which in early experiments benefited from a 50 percent to 85 percent reduction in generic usage scenarios. Additional size reduction is enabled with respect to the memory footprint of XML parsing/validation. In a CoSWID, the human-readable labels of SWID data items are replaced with more concise integer labels (indices). This approach allows SWID and CoSWID to share a common implicit information model, with CoSWID providing an alternate data model . While SWID and CoSWID are intended to share the same implicit information model, this specification does not define this information model, or a mapping between the two data formats. While an attempt to align SWID and CoSWID tags has been made here, future revisions of ISO/IEC 19770-2:2015 or this specification might cause this implicit information model to diverge, since these specifications are maintained by different standards groups. 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.

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 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 CoSWID primary or patch tags created by a software provider.

The type of a tag is determined by specific data elements, which are discussed in , which also provides normative language for CoSWID semantics that implement this lifecycle. The following information helps to explain how these semantics apply to use of a CoSWID tag.

• 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.

Use of Tag Types in the Software Lifecycle Installation -> Patching -> Upgrading -> Removal Corpus Primary Primary xPrimary xPrimary Supplemental Supplemental Supplemental xSupplemental xSupplemental Patch xPatch Primary Supplemental ]]>

• illustrates the steps in the software lifecycle and the relationships among those lifecycle events supported by the four types of SWID and CoSWID tags. A detailed description of the four tags types is provided in . The figure identifies the types of tags that are used in each lifecycle event.

There are many ways in which software tags might be managed for the host the software is installed on. For example, software tags could be made available on the host or to an external software manager when storage is limited on the host. In these cases the host or external software manager is responsible for management of the tags, including deployment and removal of the tags as indicated by the above lifecycle. Tags are deployed and previously deployed tags that are typically removed (indicated by an "x" prefix) at each lifecycle stage, 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).

Corpus tags are not actually deployed on the target system but are intended to support deployment procedures and their dependencies at install-time, such as to verify the installation media.

• • 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.
  • Software Patching. A new patch tag is provided, when a patch is applied to the software component, 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.

Note: In the context of software tagging software patching and updating differ in an important way. When installing a patch, a set of file modifications are made to pre-installed software which do not alter the version number or the descriptive metadata of an installed software component. An update can also make a set of file modifications, but the version number or the descriptive metadata of an installed software component are changed.

• • 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.

Concise SWID Format This document defines the CoSWID tag format, which is based on CBOR. 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) . The resulting CoSWID data definition is aligned to the information able to be expressed with the XML schema definition of ISO-19770-2:2015 . 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. The vocabulary, i.e., the CDDL names of the types and members used in the CoSWID CDDL specification, are mapped to more concise labels represented as small integer values (indices). The names used in the CDDL specification and the mapping to the CBOR representation using integer indices is based on the vocabulary of the XML attribute and element names defined in ISO/IEC 19770-2:2015.

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 when, and only when, they appear in all capitals, as shown here.

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 specification. This section describes the conventions by which a CoSWID is represented in the CDDL structure. The CamelCase notation used in the XML schema definition is changed to a hyphen-separated notation (e.g., ResourceCollection is named resource-collection) in the CoSWID CDDL specification. 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. In most cases, mapping attribute names between SWID and CoSWID can be done automatically by converting between CamelCase and KebabCase attribute names. However, some CoSWID CDDL attribute names show greater variation relative to their corresponding SWID XML Schema attributes. This is done when the change improves clarity in the CoSWID 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. In such cases, a manual mapping will need to be used. XPath expressions need to use SWID names, see . 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 stored or transported, as compared to the less efficient text-based form of the original vocabulary. Through use of CDDL-based integer labels, CoSWID allows for future expansion in subsequent revisions of this specification and through extensions (see ). New constructs can be associated with a new integer index. A deprecated construct can be replaced by a new construct with a new integer index. An implementation can use these integer indexes to identify the construct to parse. The CoSWID Items registry, defined in , is used to ensure that new constructs are assigned a unique index value. This approach avoids the need to have an explicit CoSWID version. In a number of places, the value encoding admits both integer values and text strings. The integer values are defined in a registry specific to the kind of value; the text values are not intended for interchange and exclusively meant for private use as defined in . Encoders SHOULD NOT use string values based on the names registered in the registry, as these values are less concise than their index value equivalent; a decoder MUST however be prepared to accept text strings that are not specified in this document (and ignore the construct if that string is unknown). In the rest of the document, we call this an "integer label with text escape". The root of the CDDL specification provided by this document is the rule coswid (as defined in ): start = coswid In CBOR, an array is encoded using bytes that identify the array, and the array's length or stop point (see ). To make items that support 1 or more values, the following CDDL notation 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 specification to allow for more efficient encoding of singleton values. Usage of this construct can be simplified using one-or-more<T> = T / [ 2* T ] simplifying the above example to _name_ = (_label_ => one-or-more<_data_>) The following subsections describe the different parts of the CoSWID model.

Character Encoding The CDDL "text" type is represented in CBOR as a major type 3, which represents "a string of Unicode characters that [are] encoded as UTF-8 " (see ). Thus both SWID and CoSWID use UTF-8 for the encoding of characters in text strings. To ensure that UTF-8 character strings are able to be encoded/decoded and exchanged interoperably, text strings in CoSWID MUST be encoded consistent with the Net-Unicode definition defined in . All names registered with IANA according to requirements in also MUST be valid according to the XML Schema NMTOKEN data type (see , Section 3.3.4) to ensure compatibility with the SWID specification where these names are used.

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

• The explicit definition of types for some attributes in the ISO-19770-2:2015 XML representation that are typically represented by the "any attribute" in the SWID model. These are covered in .
• The inclusion of extension points in the CoSWID specification using CDDL sockets (see ). 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.

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

Map Name	CDDL Socket	Defined in
concise-swid-tag	$$coswid-extension
entity-entry	$$entity-extension
link-entry	$$link-extension
software-meta-entry	$$software-meta-extension
resource-collection	$$resource-collection-extension
file-entry	$$file-extension
directory-entry	$$directory-extension
process-entry	$$process-extension
resource-entry	$$resource-extension
payload-entry	$$payload-extension
evidence-entry	$$evidence-extension

The CoSWID Items Registry defined in 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 specifications. CoSWID CDDL Enumeration Extension Points

Enumeration Name	CDDL Socket	Defined in
version-scheme	$version-scheme
role	$role
ownership	$ownership
rel	$rel
use	$use

A number of CoSWID value registries are also defined in 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 CoSWID, which can also be used by other software tagging specifications. This registration mechanism allows new standardized enumerated values to be shared between multiple tagging specifications (and associated implementations) over time.

The concise-swid-tag Map The CDDL specification 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: concise-swid-tag = { tag-id => text / bstr .size 16, tag-version => integer, ? corpus => bool, ? patch => bool, ? supplemental => bool, software-name => text, ? software-version => text, ? version-scheme => $version-scheme, ? media => text, ? software-meta => one-or-more<software-meta-entry>, entity => one-or-more<entity-entry>, ? link => one-or-more<link-entry>, ? payload-or-evidence, * $$coswid-extension, global-attributes, } payload-or-evidence //= ( payload => payload-entry ) payload-or-evidence //= ( evidence => evidence-entry ) 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 /= int / text multipartnumeric = 1 multipartnumeric-suffix = 2 alphanumeric = 3 decimal = 4 semver = 16384 The following describes each member of the concise-swid-tag root map.

• 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 .
• tag-id (index 0): A 16-byte binary string, or a textual identifier, uniquely referencing a software component. The tag identifier MUST be globally unique. Failure to ensure global uniqueness can create ambiguity in tag use since the tag-id serves as the global key for matching and lookups. If represented as a 16-byte binary string, the identifier MUST be a valid universally unique identifier as defined by . There are no strict guidelines on how the identifier is structured, but examples include a 16-byte GUID (e.g., class 4 UUID) , or a DNS domain name followed by a "/" and a text string, where the domain name serves to ensure uniqueness across organizations. A textual tag-id MUST NOT contain a sequence of two underscores ("__", see ).
• 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 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.
• 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 an 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".
• 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. 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". A patch item's value MUST NOT be set to "true" if the installation of the associated software package changes the version of a software component.
• 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".
• 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. This item maps to '/SoftwareIdentity/@name' in .
• software-version (index 13): A textual value representing the specific release or development version of the software component. This item maps to '/SoftwareIdentity/@version' in .
• version-scheme (index 14): An integer or textual value representing the versioning scheme used for the software-version item, as an integer label with text escape (, for the "Version Scheme" registry ). If an integer value is used it MUST be an index value in the range -256 to 65535. Integer values in the range -256 to -1 are reserved for testing and use in closed environments (see ). Integer values in the range 0 to 65535 correspond to registered entries in the IANA "Software ID Version Scheme Values" registry (see ).
• media (index 10): This text value is a hint to the tag consumer to understand what target platform this tag applies to. This item MUST be formatted as a query as defined by the W3C Media Queries Recommendation (see ). Support for media queries are included here for interoperability with , which does not provide any further requirements for media query use. Thus, this specification does not clarify how a media query is to be used for a CoSWID.
• 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 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 . This item maps to '/SoftwareIdentity/Meta' in .
• 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 .
• 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 , MUD resource , software download location, etc). This is modeled after the HTML "link" element. Described in .
• 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. This item is mutually exclusive to evidence, as payload can only be provided by an external entity. Described in .
• evidence (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. This item is mutually exclusive to payload, as evidence is always generated on the target device ad-hoc. Described in .
• $$coswid-extension: This CDDL socket is used to add new information structures to the concise-swid-tag root map. See .

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

• The patch and supplemental items MUST NOT both be set to "true".
• If the patch item is set to "true", the tag MUST contain at least one link item (see ) with both the rel item value of "patches" and an href item specifying an association with the software that was patched. Without at least one link item the target of the patch cannot be identified and the patch tag cannot be applied without external context.
• 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.

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 => text, * any-attribute, ) any-attribute = ( label => one-or-more<text> / one-or-more<int> ) label = text / int The following describes each child item of this group.

• lang (index 15): A textual language tag that conforms with IANA "Language Subtag Registry" . 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.
• any-attribute: This sub-group provides a means to include arbitrary information via label/index ("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.

The entity-entry Map The CDDL for the entity-entry map follows: entity-entry = { entity-name => text, ? reg-id => any-uri, role => one-or-more<$role>, ? thumbprint => hash-entry, * $$entity-extension, global-attributes, } entity-name = 31 reg-id = 32 role = 33 thumbprint = 34 $role /= tag-creator $role /= software-creator $role /= aggregator $role /= distributor $role /= licensor $role /= maintainer $role /= int / text tag-creator=1 software-creator=2 aggregator=3 distributor=4 licensor=5 maintainer=6 The following describes each child item of this group.

• global-attributes: The global-attributes group described in .
• entity-name (index 31): The textual name of the organizational entity claiming the roles specified by the role item for the CoSWID tag. This item maps to '/SoftwareIdentity/Entity/@name' in .
• 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 a registration ID MUST be a RFC 3986 URI; it is not intended to be dereferenced. The scope will usually be the scope of an organization.
• role (index 33): An integer or textual value (integer label with text escape, see ) representing the relationship(s) between the entity, and this tag or the referenced software component. If an integer value is used it MUST be an index value in the range -256 to 255. Integer values in the range -256 to -1 are reserved for testing and use in closed environments (see ). Integer values in the range 0 to 255 correspond to registered entries in the IANA "Software ID Entity Role Values" registry (see ). 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.
• thumbprint (index 34): The value of the thumbprint item provides a hash (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. See for more details on the use of the hash-entry data structure.
• $$entity-extension: This CDDL socket can be used to extend the entity-entry group model. See .

The link-entry Map The CDDL for the link-entry map follows: link-entry = { ? artifact => text, href => any-uri, ? media => text, ? ownership => $ownership, rel => $rel, ? media-type => text, ? use => $use, * $$link-extension, global-attributes, } media = 10 artifact = 37 href = 38 ownership = 39 rel = 40 media-type = 41 use = 42 $ownership /= shared $ownership /= private $ownership /= abandon $ownership /= int / text abandon=1 private=2 shared=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 /= -356..65536 / text ancestor=1 component=2 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 /= int / text optional=1 required=2 recommended=3 The following describes each member of this map.

• global-attributes: The global-attributes group described in .
• artifact (index 37): To be used with rel="installationmedia", this item's value provides the absolute filesystem 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.
• href (index 38): A URI-reference 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 ):
  • If no URI scheme is provided, then the URI-reference is a relative reference relative to the base URI of the CoSWID tag, i.e., the URI under which the CoSWID tag was provided. For example, "./folder/supplemental.coswid".
  • a physical resource location with any acceptable URI scheme (e.g., file:// http:// https:// ftp://)
  • a URI-like expression with "swid:" as the scheme refers to another SWID or CoSWID by the referenced tag's tag-id. This expression needs 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".
  • a URI-like expression with "swidpath:" as the scheme, which refers to another software tag via an XPATH query that matches items in that tag (). This scheme is provided for compatibility with . This specification does not define how to resolve an XPATH query in the context of CBOR, see .
• 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 ). As highlighted in media defined in , support for media queries are included here for interoperability with , which does not provide any further requirements for media query use. Thus, this specification does not clarify how a media query is to be used for a CoSWID.
• ownership (index 39): An integer or textual value (integer label with text escape, see , for the "Software ID Link Ownership Values" registry ) 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. If an integer value is used it MUST be an index value in the range -256 to 255. Integer values in the range -256 to -1 are reserved for testing and use in closed environments (see ). Integer values in the range 0 to 255 correspond to registered entries in the "Software ID Link Ownership Values" registry.
• rel (index 40): An integer or textual value that (integer label with text escape, see , for the "Software ID Link Relationship Values" registry ) identifies the relationship between this CoSWID and the target resource identified by the "href" item. If an integer value is used it MUST be an index value in the range -256 to 65535. Integer values in the range -256 to -1 are reserved for testing and use in closed environments (see ). Integer values in the range 0 to 65535 correspond to registered entries in the IANA "Software ID Link Relationship Values" registry (see . If a string value is used it MUST be either a private use name as defined in or a "Relation Name" from the IANA "Link Relation Types" registry: https://www.iana.org/assignments/link-relations/link-relations.xhtml as defined by . When a string value defined in the IANA "Software ID Link Relationship Values" registry matches a Relation Name defined in the IANA "Link Relation Types" registry, the index value in the IANA "Software ID Link Relationship Values" registry MUST be used instead, as this relationship has a specialized meaning in the context of a CoSWID tag. String values correspond to registered entries in the "Software ID Link Relationship Values" registry.
• 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. (This is a hint: There is no obligation for the server hosting the target of the URI to use the indicated media type when the URI is dereferenced.) Media types are identified by referencing a "Name" from the IANA "Media Types" registry: http://www.iana.org/assignments/media-types/media-types.xhtml. This item maps to '/SoftwareIdentity/Link/@type' in .
• use (index 42): An integer or textual value (integer label with text escape, see , for the "Software ID Link Relationship Values" registry ) used to determine if the referenced software component has to be installed before installing the software component identified by the COSWID tag. If an integer value is used it MUST be an index value in the range -256 to 255. Integer values in the range -256 to -1 are reserved for testing and use in closed environments (see ). Integer values in the range 0 to 255 correspond to registered entries in the IANA "Link Use Values" registry (see . If a string value is used it MUST be a private use name as defined in . String values correspond to registered entries in the "Software ID Link Use Values" registry.
• $$link-extension: This CDDL socket can be used to extend the link-entry map model. See .

The software-meta-entry Map The CDDL for the software-meta-entry map follows: software-meta-entry = { ? activation-status => text, ? channel-type => text, ? colloquial-version => text, ? description => text, ? edition => text, ? entitlement-data-required => bool, ? entitlement-key => text, ? generator => text / bstr .size 16, ? persistent-id => text, ? product => text, ? product-family => text, ? revision => text, ? summary => text, ? unspsc-code => text, ? unspsc-version => text, * $$software-meta-extension, global-attributes, } 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 The following describes each child item of this group.

• global-attributes: The global-attributes group described in .
• 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.
• channel-type (index 44): A textual value that identifies 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.
• 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 (byte-by-byte) only and is not intended to be used to determine if a specific value is earlier or later in a sequence.
• description (index 46): A textual value that provides a detailed description of the software component. This value MAY be multiple paragraphs separated by CR LF characters as described by .
• 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 example, this item can be used to differentiate enterprise, standard, or professional variants of a software component.
• 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.
• entitlement-key (index 49): A vendor-specific textual key that can be used to identify and establish a relationship to an 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. Since CoSWID tags are not intended to contain confidential information, tag authors are advised not to record unprotected, private software license keys in this field.
• 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.
• 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.
• product (index 52): A basic name for the software component that can be common across multiple tagged software components (e.g., Apache HTTPD).
• 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.
• 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.
• summary (index 55): A short description of the software component. This MUST be a single sentence suitable for display in a user interface.
• unspsc-code (index 56): An 8 digit UNSPSC classification code for the software component as defined by the United Nations Standard Products and Services Code (UNSPSC, ).
• unspsc-version (index 57): The version of UNSPSC used to define the unspsc-code value.
• $$meta-extension: This CDDL socket can be used to extend the software-meta-entry group model. See .

The Resource Collection Definition

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 member (index 7) and the corresponding hash-entry type. This is the equivalent of the namespace qualified "hash" attribute in . hash-entry = [ hash-alg-id: int, hash-value: bytes, ] The number used as a value for hash-alg-id is an integer-based hash algorithm identifier who's value MUST refer to an ID in the IANA "Named Information Hash Algorithm Registry" with a Status of "current" (at the time the generator software was built or later); other hash algorithms MUST NOT be used. If the hash-alg-id is not known, then the integer value "0" MUST be used. This allows for conversion from ISO SWID tags , which do not allow an algorithm to be identified for this field. The hash-value MUST represent the raw hash value as a byte string (as opposed to, e.g., base64 encoded) generated from the representation of the resource using the hash algorithm indicated by hash-alg-id.

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: path-elements-group = ( ? directory => one-or-more<directory-entry>, ? file => one-or-more<file-entry>, ) resource-collection = ( path-elements-group, ? process => one-or-more<process-entry>, ? resource => one-or-more<resource-entry>, * $$resource-collection-extension, ) filesystem-item = ( ? key => bool, ? location => text, fs-name => text, ? root => text, ) file-entry = { filesystem-item, ? size => uint, ? file-version => text, ? hash => hash-entry, * $$file-extension, global-attributes, } directory-entry = { filesystem-item, ? path-elements => { path-elements-group }, * $$directory-extension, global-attributes, } process-entry = { process-name => text, ? pid => integer, * $$process-extension, global-attributes, } resource-entry = { type => text, * $$resource-extension, global-attributes, } 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 The following describes each member of the groups and maps illustrated above.

• filesystem-item: A list of common items used for representing the filesystem root, relative location, name, and significance of a file or directory item.
• global-attributes: The global-attributes group described in .
• directory (index 16): A directory item allows child directory and file items to be defined within a directory hierarchy for the software component.
• file (index 17): A file item allows details about a file to be provided for the software component.
• 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.
• 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 is currently under specified. As a result, this item might be further defined through extension in the future.
• size (index 20): The file's size in bytes.
• file-version (index 21): The file's version as reported by querying information on the file from the operating system (if available). This item maps to '/SoftwareIdentity/(Payload|Evidence)/File/@version' in .
• hash (index 7): A hash of the file as described in .
• 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.
• 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 (as indicated in the location value in the evidence entry map) if no parent is defined. The location MUST NOT include a file's name, which is provided by the fs-name item.
• fs-name (index 24): The name of the directory or file without any path information. This aligns with a file "name" in . This item maps to '/SoftwareIdentity/(Payload|Evidence)/(File|Directory)/@name' in .
• root (index 25): A host-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.
• path-elements (index 26): This group allows a hierarchy of directory and file items to be defined in payload or evidence items. This is a construction within the CDDL definition of CoSWID to support shared syntax and does not appear in .
• process-name (index 27): The software component's process name as it will appear in an endpoint's process list. This aligns with a process "name" in . This item maps to '/SoftwareIdentity/(Payload|Evidence)/Process/@name' in .
• 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.
• type (index 29): A human-readable string indicating the type of resource.
• $$resource-collection-extension: This CDDL socket can be used to extend the resource-collection group model. This can be used to add new specialized types of resources. See .
• $$file-extension: This CDDL socket can be used to extend the file-entry group model. See .
• $$directory-extension: This CDDL socket can be used to extend the directory-entry group model. See .
• $$process-extension: This CDDL socket can be used to extend the process-entry group model. See .
• $$resource-extension: This CDDL socket can be used to extend the resource-entry group model. See .

The payload-entry Map The CDDL for the payload-entry map follows: payload-entry = { resource-collection, * $$payload-extension, global-attributes, } The following describes each child item of this group.

• global-attributes: The global-attributes group described in .
• resource-collection: The resource-collection group described in .
• $$payload-extension: This CDDL socket can be used to extend the payload-entry group model. See .

The evidence-entry Map The CDDL for the evidence-entry map follows: evidence-entry = { resource-collection, ? date => integer-time, ? device-id => text, ? location => text, * $$evidence-extension, global-attributes, } date = 35 device-id = 36 The following describes each child item of this group.

• global-attributes: The global-attributes group described in .
• resource-collection: The resource-collection group described in .
• date (index 35): The date and time the information was collected pertaining to the evidence item in Epoch-Based Date/Time format as specified in .
• device-id (index 36): The endpoint's string identifier from which the evidence was collected.
• location (index 23): The absolute filepath of the location of the CoSWID tag generated as evidence. (Location values in filesystem-items in the payload can be expressed relative to this location.)
• $$evidence-extension: This CDDL socket can be used to extend the evidence-entry group model. See .

Full CDDL Specification In order to create a valid CoSWID document the structure of the corresponding CBOR message MUST adhere to the following CDDL specification. concise-swid-tag = { tag-id => text / bstr .size 16, tag-version => integer, ? corpus => bool, ? patch => bool, ? supplemental => bool, software-name => text, ? software-version => text, ? version-scheme => $version-scheme, ? media => text, ? software-meta => one-or-more<software-meta-entry>, entity => one-or-more<entity-entry>, ? link => one-or-more<link-entry>, ? payload-or-evidence, * $$coswid-extension, global-attributes, } payload-or-evidence //= ( payload => payload-entry ) payload-or-evidence //= ( evidence => evidence-entry ) any-uri = uri label = text / int $version-scheme /= multipartnumeric $version-scheme /= multipartnumeric-suffix $version-scheme /= alphanumeric $version-scheme /= decimal $version-scheme /= semver $version-scheme /= int / text any-attribute = ( label => one-or-more<text> / one-or-more<int> ) one-or-more<T> = T / [ 2* T ] global-attributes = ( ? lang => text, * any-attribute, ) hash-entry = [ hash-alg-id: int, hash-value: bytes, ] entity-entry = { entity-name => text, ? reg-id => any-uri, role => one-or-more<$role>, ? thumbprint => hash-entry, * $$entity-extension, global-attributes, } $role /= tag-creator $role /= software-creator $role /= aggregator $role /= distributor $role /= licensor $role /= maintainer $role /= int / text link-entry = { ? artifact => text, href => any-uri, ? media => text, ? ownership => $ownership, rel => $rel, ? media-type => text, ? use => $use, * $$link-extension, global-attributes, } $ownership /= shared $ownership /= private $ownership /= abandon $ownership /= int / text $rel /= ancestor $rel /= component $rel /= feature $rel /= installationmedia $rel /= packageinstaller $rel /= parent $rel /= patches $rel /= requires $rel /= see-also $rel /= supersedes $rel /= supplemental $rel /= -256..64436 / text $use /= optional $use /= required $use /= recommended $use /= int / text software-meta-entry = { ? activation-status => text, ? channel-type => text, ? colloquial-version => text, ? description => text, ? edition => text, ? entitlement-data-required => bool, ? entitlement-key => text, ? generator => text / bstr .size 16, ? persistent-id => text, ? product => text, ? product-family => text, ? revision => text, ? summary => text, ? unspsc-code => text, ? unspsc-version => text, * $$software-meta-extension, global-attributes, } path-elements-group = ( ? directory => one-or-more<directory-entry>, ? file => one-or-more<file-entry>, ) resource-collection = ( path-elements-group, ? process => one-or-more<process-entry>, ? resource => one-or-more<resource-entry>, * $$resource-collection-extension, ) file-entry = { filesystem-item, ? size => uint, ? file-version => text, ? hash => hash-entry, * $$file-extension, global-attributes, } directory-entry = { filesystem-item, ? path-elements => { path-elements-group }, * $$directory-extension, global-attributes, } process-entry = { process-name => text, ? pid => integer, * $$process-extension, global-attributes, } resource-entry = { type => text, * $$resource-extension, global-attributes, } filesystem-item = ( ? key => bool, ? location => text, fs-name => text, ? root => text, ) payload-entry = { resource-collection, * $$payload-extension, global-attributes, } evidence-entry = { resource-collection, ? date => integer-time, ? device-id => text, ? location => text, * $$evidence-extension, global-attributes, } integer-time = #6.1(int) ; "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 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 multipartnumeric-suffix = 2 alphanumeric = 3 decimal = 4 semver = 16384 ; "role" integer indexes tag-creator=1 software-creator=2 aggregator=3 distributor=4 licensor=5 maintainer=6 ; "ownership" integer indexes abandon=1 private=2 shared=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 ; this is already defined earlier ; "use" integer indexes optional=1 required=2 recommended=3

Determining the Type of CoSWID The operational model for SWID and CoSWID tags was introduced in , 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".
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".

CoSWID Indexed Label Values This section defines a number of kinds of indexed label values that are maintained in a registry each (). These values are represented as positive integers. In each registry, the value 0 is marked as Reserved.

Version Scheme The following table contains a set of values for use in the concise-swid-tag group's version-scheme item. Version Scheme Name strings match the version schemes defined in the ISO/IEC 19770-2:2015 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. Version Scheme Values

Index	Version Scheme Name	Definition
1	multipartnumeric	Numbers separated by dots, where the numbers are interpreted as decimal integers (e.g., 1.2.3, 1.2.3.4.5.6.7, 1.4.5, 1.21)
2	multipartnumeric+suffix	Numbers separated by dots, where the numbers are interpreted as decimal integers with an additional textual suffix (e.g., 1.2.3a)
3	alphanumeric	Strictly a string, no interpretation as number
4	decimal	A single decimal floating point number
16384	semver	A semantic version as defined by . Also see the specification for more information

multipartnumeric and the numbers part of multipartnumeric+suffix are interpreted as a sequence of numbers and are sorted in lexicographical order by these numbers (i.e., not by the digits in the numbers) and then the textual suffix (for multipartnumeric+suffix). Alphanumeric strings are sorted lexicographically as character strings. Decimal version numbers are interpreted as a single floating point number (e.g., 1.25 is less than 1.3). The values above are registered in the IANA "Software ID Version Scheme Values" registry defined in . Additional entries will likely be registered over time in this registry. A CoSWID producer that is aware of the version scheme that has been used to select the version value, SHOULD include the optional version-scheme item to avoid semantic ambiguity. If the CoSWID producer does not have this information, it SHOULD omit the version-scheme item. The following heuristics can be used by a CoSWID consumer, based on the version schemes' partially overlapping value spaces:

• "decimal" and "multipartnumeric" partially overlap in their value space when a value matches a decimal number. When a corresponding software-version item's value falls within this overlapping value space, it is expected that the "decimal" version scheme is used.
• "multipartnumeric" and "semver" partially overlap in their value space when a "multipartnumeric" value matches the semantic versioning syntax. When a corresponding software-version item's value falls within this overlapping value space, it is expected that the "semver" version scheme is used.
• "alphanumeric" and other version schemes might overlap in their value space. When a corresponding software-version item's value falls within this overlapping value space, it is expected that the other version scheme is used and "alphanumeric" is not used.

Note that these heuristics are imperfect and can guess wrong, which is the reason the version-scheme item SHOULD be included by the producer.

Entity Role Values The following table indicates the index value to use for the entity-entry group's role item (see ). These values match the entity roles defined in the ISO/IEC 19770-2:2015 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. Entity Role Values

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 , "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 , "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 as "software licensor", a "person or organization who owns or holds the rights to issue a software license for a specific software [component]"
6	maintainer	The person or organization that is responsible for coordinating and making updates to the source code for the software component. This SHOULD be used when the "maintainer" is a different person or organization than the original "softwareCreator".

The values above are registered in the IANA "Software ID Entity Role Values" registry defined in . Additional values will likely be registered over time.

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

Index	Ownership Type	Definition
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.

The values above are registered in the IANA "Software ID Link Ownership Values" registry defined in . Additional values will likely be registered over time.

Link Rel Values The following table indicates the index value to use for the link-entry group's rel item (see ). These values match the link rel values defined in the ISO/IEC 19770-2:2015 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. Link Relationship Values

Index	Relationship Type	Definition
1	ancestor	The link references a software tag for a previous release of this software. This can be useful to define an upgrade path.
2	component	The link references a software 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 software tag that is the parent of the referencing tag. This relationship can be used when multiple software components are part of a software bundle, where the "parent" is the software 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 software tag, and the bundle can provide a "component" link relationship to each child software component.
7	patches	The link references a software tag that the referencing software patches. Typically only used for patch tags (see ).
8	requires	The link references a prerequisite for installing this software. A patch tag (see ) 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.
10	supersedes	The link references another software that this software replaces. A patch tag (see ) can use this to represent another patch that this patch incorporates or replaces.
11	supplemental	The link references a software tag that the referencing tag supplements. Used on supplemental tags (see ).

The values above are registered in the IANA "Software ID Link Relationship Values" registry defined in . Additional values will likely be registered over time.

Link Use Values The following table indicates the index value to use for the link-entry group's use item (see ). These values match the link use values defined in the ISO/IEC 19770-2:2015 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. Link Use Values

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

The values above are registered in the IANA "Software ID Link Use Values" registry defined in . Additional values will likely be registered over time.

swid and swidpath Expressions This specification defines the following expressions for use in CoSWID and to provide interoperability with schemes used in . Because both the "swid" and "swidpath" schemes are to be interpreted within a local, rather than a global, context, neither of these scheme are URIs as defined in and the swid and swidpath scheme names are not registered as permanent schemes with IANA. That noted, swid and swidpath expressions conform to all rules for URI syntax. All uses of these expressions encountered within a CoSWID are to be interpreted as described in this section. RFC Ed.: throughout this section, please replace RFC-AAAA with the RFC number of this specification and remove this note.

"swid" Expressions Expressions specifying the "swid" scheme are used to reference a software tag by its tag-id. A tag-id referenced in this way can be used to identify the tag resource in the context of where it is referenced from. For example, when a tag is installed on a given device, that tag can reference related tags on the same device using expressions with this scheme. For expressions that use the "swid" scheme, the scheme specific part MUST consist of a referenced software tag's tag-id. This tag-id MUST be URI encoded according to Section 2.1. The following expression is a valid example:

"swidpath" Expressions Expressions specifying the "swidpath" scheme are used to filter tags out of a base collection, so that matching tags are included in the identified tag collection. The XPath expression references the data that must be found in a given software tag out of base collection for that tag to be considered a matching tag. Tags to be evaluated (the base collection) include all tags in the context of where the swidpath expression is referenced from. For example, when a tag is installed on a given device, that tag can reference related tags on the same device using an expression with this scheme. For URIs that use the "swidpath" scheme, the following requirements apply:

• The scheme specific part MUST be an XPath expression as defined by . The included XPath expression will be URI encoded according to .
• This XPath is evaluated over SWID tags, or COSWID tags transformed into SWID tags, found on a system. A given tag MUST be considered a match if the XPath evaluation result value has an effective boolean value of "true" according to , Section 2.4.3.

IANA Considerations This document has a number of IANA considerations, as described in the following subsections. In summary, 6 new registries are established with this request, with initial entries provided for each registry. New values for 5 other registries are also requested.

CoSWID Items Registry This registry uses integer values as index values in CBOR maps. This document defines a new registry titled "CoSWID Items". Future registrations for this registry are to be made based on as follows: CoSWID Items Registration Procedures

Range	Registration Procedures
0-32767	Standards Action with Expert Review
32768-4294967295	Specification Required

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. CoSWID Items Initial Registrations

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
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
29	type	RFC-AAAA
30	Unassigned
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
54	revision	RFC-AAAA
55	summary	RFC-AAAA
56	unspsc-code	RFC-AAAA
57	unspsc-version	RFC-AAAA
58-4294967295	Unassigned

Software ID Values Registries The following IANA registries provide a mechanism for new values to be added over time to common enumerations used by SWID and CoSWID. While neither the CoSWID nor SWID specification is subordinate to the other and will evolve as their respective standards group chooses, there is value in supporting alignment between the two standards. Shared use of common code points, as spelled out in these registries, will facilitate this alignment, hence the intent for shared use of these registries and the decision to use "swidsoftware-id" (rather than "swid" or "coswid") in registry names.

Registration Procedures The following registries allow for the registration of index values and names. New registrations will be permitted through either a Standards Action with Expert Review policy or a Specification Required policy . The following registries also reserve the integer-based index values in the range of -1 to -256 for private use as defined by . This allows values -1 to -24 to be expressed as a single uint_8t in CBOR, and values -25 to -256 to be expressed using an additional uint_8t in CBOR.

Private Use of Index and Name Values The integer-based index values in the private use range (-1 to -256) are intended for testing purposes and closed environments; values in other ranges SHOULD NOT be assigned for testing. For names that correspond to private use index values, an Internationalized Domain Name prefix MUST be used to prevent name conflicts using the form: Where both "domainprefix" and "name" MUST each be either an NR-LDH label or a U-label as defined by , and "name" also MUST be a unique name within the namespace defined by the "domainprefix". Use of a prefix in this way allows for a name to be used in the private use range. This is consistent with the guidance in .

Expert Review Criteria Designated experts MUST ensure that new registration requests meet the following additional criteria:

• The requesting specification MUST provide a clear semantic definition for the new entry. This definition MUST clearly differentiate the requested entry from other previously registered entries.
• The requesting specification MUST describe the intended use of the entry, including any co-constraints that exist between the use of the entry's index value or name, and other values defined within the SWID/CoSWID model.
• Index values and names outside the private use space MUST NOT be used without registration. This is considered squatting and MUST be avoided. Designated experts MUST ensure that reviewed specifications register all appropriate index values and names.
• Standards track documents MAY include entries registered in the range reserved for entries under the Specification Required policy. This can occur when a standards track document provides further guidance on the use of index values and names that are in common use, but were not registered with IANA. This situation SHOULD be avoided.
• All registered names MUST be valid according to the XML Schema NMTOKEN data type (see , Section 3.3.4). This ensures that registered names are compatible with the SWID format where they are used.
• Registration of vanity names SHOULD be discouraged. The requesting specification MUST provide a description of how a requested name will allow for use by multiple stakeholders.

Software ID Version Scheme Values Registry This document establishes a new registry titled "Software ID Version Scheme Values". This registry provides index values for use as version-scheme item values in this document and version scheme names for use in . [TO BE REMOVED: This registration should take place at the following location: https://www.iana.org/assignments/software-id] This registry uses the registration procedures defined in with the following associated ranges: Software ID Version Scheme Registration Procedures

Range	Registration Procedures
0-16383	Standards Action with Expert Review
16384-65535	Specification Required

Assignments MUST consist of an integer Index value, the Version Scheme Name, and a reference to the defining specification. Initial registrations for the "Software ID Version Scheme Values" registry are provided below, which are derived from the textual version scheme names defined in . Software ID Version Scheme Initial Registrations

Index	Version Scheme Name	Specification
0	Reserved
1	multipartnumeric	See
2	multipartnumeric+suffix	See
3	alphanumeric	See
4	decimal	See
5-16383	Unassigned
16384	semver	See
16385-65535	Unassigned

Registrations MUST conform to the expert review criteria defined in . Designated experts MUST also ensure that newly requested entries define a value space for the corresponding version item that is unique from other previously registered entries. Note: The initial registrations violate this requirement, but are included for backwards compatibility with . See also .

Software ID Entity Role Values Registry This document establishes a new registry titled "Software ID Entity Role Values". This registry provides index values for use as entity-entry role item values in this document and entity role names for use in . [TO BE REMOVED: This registration should take place at the following location: https://www.iana.org/assignments/software-id] This registry uses the registration procedures defined in with the following associated ranges: Software ID Entity Role Registration Procedures

Range	Registration Procedures
0-127	Standards Action with Expert Review
128-255	Specification Required

Assignments consist of an integer Index value, a Role Name, and a reference to the defining specification. Initial registrations for the "Software ID Entity Role Values" registry are provided below, which are derived from the textual entity role names defined in . Software ID Entity Role Initial Registrations

Index	Role Name	Specification
0	Reserved
1	tagCreator	See
2	softwareCreator	See
3	aggregator	See
4	distributor	See
5	licensor	See
6	maintainer	See
7-255	Unassigned

Registrations MUST conform to the expert review criteria defined in .

Software ID Link Ownership Values Registry This document establishes a new registry titled "Software ID Link Ownership Values". This registry provides index values for use as link-entry ownership item values in this document and link ownership names for use in . [TO BE REMOVED: This registration should take place at the following location: https://www.iana.org/assignments/software-id] This registry uses the registration procedures defined in with the following associated ranges: Software ID Link Ownership Registration Procedures

Range	Registration Procedures
0-127	Standards Action with Expert Review
128-255	Specification Required

Assignments consist of an integer Index value, an Ownership Type Name, and a reference to the defining specification. Initial registrations for the "Software ID Link Ownership Values" registry are provided below, which are derived from the textual entity role names defined in . Software ID Link Ownership Inital Registrations

Index	Ownership Type Name	Definition
0	Reserved
1	abandon	See
2	private	See
3	shared	See
4-255	Unassigned

Registrations MUST conform to the expert review criteria defined in .

Software ID Link Relationship Values Registry This document establishes a new registry titled "Software ID Link Relationship Values". This registry provides index values for use as link-entry rel item values in this document and link ownership names for use in . [TO BE REMOVED: This registration should take place at the following location: https://www.iana.org/assignments/software-id] This registry uses the registration procedures defined in with the following associated ranges: Software ID Link Relationship Registration Procedures

Range	Registration Procedures
0-32767	Standards Action with Expert Review
32768-65535	Specification Required

Assignments consist of an integer Index value, the Relationship Type Name, and a reference to the defining specification. Initial registrations for the "Software ID Link Relationship Values" registry are provided below, which are derived from the link relationship values defined in . Software ID Link Relationship Initial Registrations

Index	Relationship Type Name	Specification
0	Reserved
1	ancestor	See
2	component	See
3	feature	See
4	installationmedia	See
5	packageinstaller	See
6	parent	See
7	patches	See
8	requires	See
9	see-also	See
10	supersedes	See
11	supplemental	See
12-65535	Unassigned

Registrations MUST conform to the expert review criteria defined in . Designated experts MUST also ensure that a newly requested entry documents the URI schemes allowed to be used in an href associated with the link relationship and the expected resolution behavior of these URI schemes. This will help to ensure that applications processing software tags are able to interoperate when resolving resources referenced by a link of a given type.

Software ID Link Use Values Registry This document establishes a new registry titled "Software ID Link Use Values". This registry provides index values for use as link-entry use item values in this document and link use names for use in . [TO BE REMOVED: This registration should take place at the following location: https://www.iana.org/assignments/software-id] This registry uses the registration procedures defined in with the following associated ranges: Software ID Link Use Registration Procedures

Range	Registration Procedures
0-127	Standards Action with Expert Review
128-255	Specification Required

Assignments consist of an integer Index value, the Link Use Type Name, and a reference to the defining specification. Initial registrations for the "Software ID Link Use Values" registry are provided below, which are derived from the link relationship values defined in . Software ID Link Use Initial Registrations

Index	Link Use Type Name	Specification
0	Reserved
1	optional	See
2	required	See
3	recommended	See
4-255	Unassigned

Registrations MUST conform to the expert review criteria defined in .

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: Binary (encoded as CBOR ). See RFC-AAAA for details. Security considerations: See 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: The syntax and semantics of fragment identifiers specified for "application/swid+cbor" are as specified for "application/cbor". (At publication of RFC-AAAA, there is no fragment identification syntax defined for "application/cbor".) Additional information: Magic number(s): if tagged, first five bytes in hex: da 53 57 49 44 (see in RFC-AAAA) File extension(s): coswid Macintosh file type code(s): none Macintosh Universal Type Identifier code: org.ietf.coswid conforms to public.data Person & email address to contact for further information: IESG <iesg@ietf.org> Intended usage: COMMON Restrictions on usage: None Author: Henk Birkholz <henk.birkholz@sit.fraunhofer.de> Change controller: IESG

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 : CoAP Content-Format IDs

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

CBOR Tag Registration IANA is requested to allocate a tag in the "CBOR Tags" registry , preferably with the specific value requested: CoSWID CBOR Tag

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

CoSWID Model for use in SWIMA Registration The Software Inventory Message and Attributes (SWIMA) for PA-TNC specification defines a standardized method for collecting an endpoint device's software inventory. A CoSWID can provide evidence of software installation which can then be used and exchanged with SWIMA. This registration adds a new entry to the IANA "Software Data Model Types" registry defined by to support CoSWID use in SWIMA as follows: Pen: 0 Integer: TBD2 Name: Concise Software Identifier (CoSWID) Reference: RFC-AAAA Deriving Software Identifiers: A Software Identifier generated from a CoSWID tag is expressed as a concatenation of the form in as follows: Where TAG_CREATOR_REGID is the reg-id item value of the tag's entity item having the role value of 1 (corresponding to "tag creator"), and the UNIQUE_ID is the same tag's tag-id item. If the tag-id item's value is expressed as a 16-byte binary string, the UNIQUE_ID MUST be represented using the UUID string representation defined in including the "urn:uuid:" prefix. The TAG_CREATOR_REGID and the UNIQUE_ID are connected with a double underscore (_), without any other connecting character or whitespace.

Signed CoSWID Tags 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. Signing CoSWID tags follows the procedures defined in CBOR Object Signing and Encryption . A CoSWID tag MUST be wrapped in a COSE Signature structure, either COSE_Sign1 or COSE_Sign. In the first case, a Single Signer Data Object (COSE_Sign1) contains a single signature and MUST be signed by the tag creator. The following CDDL specification defines a restrictive subset of COSE header parameters that MUST be used in the protected header in this case. COSE-Sign1-coswid<payload> = [ protected: bstr .cbor protected-signed-coswid-header, unprotected: unprotected-signed-coswid-header, payload: bstr .cbor payload, signature: bstr, ] 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 = { * cose-label => cose-values, } The COSE_Sign structure allows for more than one signature, one of which MUST be issued by the tag creator, to be applied to a CoSWID tag and MAY be used. The corresponding usage scenarios are domain-specific and require well-specified application guidance. COSE-Sign-coswid<payload> = [ protected: bstr .cbor protected-signed-coswid-header1, unprotected: unprotected-signed-coswid-header, payload: bstr .cbor payload, signature: [ * COSE_Signature ], ] protected-signed-coswid-header1 = { 3 => "application/swid+cbor", * cose-label => cose-values, } protected-signature-coswid-header = { 1 => int, ; algorithm identifier * cose-label => cose-values, } unprotected-signed-coswid-header = { * cose-label => cose-values, } COSE_Signature = [ protected: bstr .cbor protected-signature-coswid-header, unprotected: unprotected-signed-coswid-header, signature : bstr ] 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). A CoSWID MUST be signed, using the above mechanism, to protect the integrity of the CoSWID tag. See the security considerations (in ) for more information on why a signed CoSWID is valuable in most cases.

CBOR-Tagged CoSWID Tags This specification allows for tagged and untagged CBOR data items that are CoSWID tags. Consecutively, the CBOR tag for CoSWID tags defined in SHOULD be used in conjunction with CBOR data items that are a CoSWID tags. Other CBOR tags MUST NOT be used with a CBOR data item that is a CoSWID tag. If tagged, both signed and unsigned CoSWID tags MUST use the CoSWID CBOR tag. In case a signed CoSWID is tagged, a CoSWID CBOR tag MUST be appended before the COSE envelope whether it is a COSE_Untagged_Message or a COSE_Tagged_Message. In case an unsigned CoSWID is tagged, a CoSWID CBOR tag MUST be appended before the CBOR data item that is the CoSWID tag. coswid = unsigned-coswid / signed-coswid unsigned-coswid = concise-swid-tag / tagged-coswid<concise-swid-tag> signed-coswid1 = signed-coswid-for<unsigned-coswid> signed-coswid = signed-coswid1 / tagged-coswid<signed-coswid1> tagged-coswid<T> = #6.1398229316(T) signed-coswid-for<payload> = #6.18(COSE-Sign1-coswid<payload>) / #6.98(COSE-Sign-coswid<payload>) This specification allows for a tagged CoSWID tag to reside in a COSE envelope that is also tagged with a CoSWID CBOR tag. In cases where a tag creator is not a signer (e.g., hand-offs between entities in a trusted portion of a supply-chain), retaining CBOR tags attached to unsigned CoSWID tags can be of great use. Nevertheless, redundant use of tags SHOULD be avoided when possible.

Security Considerations The following security considerations for use of CoSWID tags focus on:

• ensuring the integrity and authenticity of a CoSWID tag
• the application of CoSWID tags to address security challenges related to unmanaged or unpatched software
• reducing the potential for unintended disclosure of a device's software load

A tag is considered "authoritative" if the CoSWID tag was created by the software provider. An authoritative CoSWID tag contains information about a software component provided by the supplier of the software component, who is expected to be an expert in their own software. Thus, authoritative CoSWID tags can represent authoritative information about the software component. The degree to which this information can be trusted depends on the tag's chain of custody and the ability to verify a signature provided by the supplier if present in the CoSWID tag. The provisioning and validation of CoSWID tags are handled by local policy and is outside the scope of this document. A signed CoSWID tag (see ) whose signature has been validated can be relied upon to be unchanged since it was signed. By contrast, the data contained in unsigned tags can be altered by any user or process with write-access to the tag. To support signature validation, there is the need to associate the right key with the software provider or party originating the signature in a secure way. This operation is application specific and needs to be addressed by the application or a user of the application; a specific approach for which is out-of-scope for this document. When an authoritative tag is signed, the originator of the signature can be verified. A trustworthy association between the signature and the originator of the signature can be established via trust anchors. A certification path between a trust anchor and a certificate including a public key enabling the validation of a tag signature can realize the assessment of trustworthiness of an authoritative tag. Verifying that the software provider is the signer is a different matter. This requires an association between the signature and the tag's entity item associated corresponding to the software provider. No mechanism is defined in this draft to make this association; therefore, this association will need to be handled by local policy. As always, the validity of a signature does not imply veracity of the signed statements: anyone can sign assertions such that the software is from a specific software-creator or that a specific persistent-id applies; policy needs to be applied to evaluate these statements and to determine their suitability for a specific use. Loss of control of signing credentials used to sign CoSWID tags would create doubt about the authenticity and integrity of any CoSWID tags signed using the compromised keys. In such cases, the legitimate tag signer (namely, the software provider for an authoritative CoSWID tag) can employ uncompromised signing credentials to create a new signature on the original tag. The tag version number would not be incremented since the tag itself was not modified. Consumers of CoSWID tags would need to validate the tag using the new credentials and would also need to make use of revocation information available for the compromised credentials to avoid validating tags signed with them. The process for doing this is beyond the scope of this specification. The CoSWID format allows the use of hash values without an accompanying hash algorithm identifier. This exposes the tags to some risk of cross-algorithm attacks. We believe that this can become a practical problem only if some implementations allow the use of insecure hash algorithms. Since it may not become known immediately when an algorithm becomes insecure, this leads to a strong recommendation to only include support for hash algorithms that are generally considered secure, and not just marginally so. CoSWID tags are intended to contain public information about software components and, as such, the contents of a CoSWID tag (as opposed to the set of tags that apply to the endpoint, see below) does not need to be protected against unintended disclosure on an endpoint. Conversely, generators of CoSWID tags need to ensure that only public information is disclosed. Entitlement Keys are an example for information where particular care is required; tag authors are advised not to record unprotected, private software license keys in this field. CoSWID tags are intended to be easily discoverable by authorized applications and users on an endpoint in order to make it easy to determine the tagged software load. Access to the collection of an endpoint's CoSWID tags needs to be appropriately controlled to authorized applications and users using an appropriate access control mechanism. Since the tag-id of a CoSWID tag can be used as a global index value, failure to ensure the tag-id's uniqueness can cause collisions or ambiguity in CoSWID tags that are retrieved or processed using this identifier. CoSWID is designed to not require a registry of identifiers. As a result, CoSWID requires the tag creator to employ a method of generating a unique tag identifier. Specific methods of generating a unique identifier are beyond the scope of this specification. A collision in tag-ids may result in false positives/negatives in software integrity checks or mis-identification of installed software, undermining CoSWID use cases such as vulnerability identification, software inventory, etc. If such a collision is detected, then the tag consumer may want to contact the maintainer of the CoSWID to have them issue a correction addressing the collision; however, this also discloses to the maintainer that the consumer has the other tag with the given tag-id in their database. More generally speaking, a tag consumer needs to be robust against such collisions lest the collision become a viable attack vector. 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 CoSWID tags can be similarly controlled. On more open systems, where many users can manage the software inventory, CoSWID tags can be easier to add or remove. On such systems, it can be possible to add or remove 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 CoSWID tags, so products can be present on an endpoint without providing a corresponding CoSWID tag. As such, any collection of 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, CoSWID tags are an easy way to provide a preliminary understanding of that endpoint's software inventory. As CoSWID tags do not expire, inhibiting new CoSWID tags from reaching an intended consumer would render that consumer stuck with outdated information, potentially leaving associated vulnerabilities or weaknesses unmitigated. Therefore, a CoSWID tag consumer should actively check for updated tag-versions via more than one means. This specification makes use of relative paths (e.g., filesystem paths) in several places. A signed COSWID tag cannot make use of these to derive information that is considered to be covered under the signature. Typically, relative file system paths will be used to identify targets for an installation, not sources of tag information. Any report of an endpoint's 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, CoSWID tags are designed to be easily discoverable by authorized applications and users on 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 CoSWID tag information that has been collected from an endpoint in transit and at rest, not because those tags individually contain sensitive information, but because the collection of 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 CDDL specification 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, CoSWID tags can be created by any party and the CoSWID tags collected from an endpoint could contain a mixture of vendor and non-vendor created tags. For this reason, a CoSWID tag might contain potentially malicious content. Input sanitization, loop detection, and signature verification are ways that implementations can address this concern. More generally speaking, the security considerations of , , and apply.

Privacy Consideration As noted in , collected information about an endpoint's software load, such as what might be represented by an endpoint's CoSWID tag collection, could be used to identify vulnerable software for attack. Collections of endpoint software information also can have privacy implications for users. The set of application a user installs can give clues to personal matters such as political affiliation, banking and investments, gender, sexual orientation, medical concerns, etc. While the collection of CoSWID tags on an endpoint wouldn't increase the privacy risk (since a party able to view those tags could also view the applications themselves), if those CoSWID tags are gathered and stored in a repository somewhere, visibility into the repository now also gives visibility into a user's application collection. For this reason, repositories of collected CoSWID tags not only need to be protected against collection by malicious parties, but even authorized parties will need to be vetted and made aware of privacy responsibilities associated with having access to this information. Likewise, users should be made aware that their software inventories are being collected from endpoints. Furthermore, when collected and stored by authorized parties or systems, the inventory data needs to be protected as both security and privacy-sensitive information.

Change Log [THIS SECTION TO BE REMOVED BY THE RFC EDITOR.] Changes from version 22 to version 23

• Removed request for IANA registration of swid and swidpath as URI schemes. Updated text to note that that these are not URIs but expressions that follow URI syntax

Changes from version 12 to version 14:

• Moved key identifier to protected COSE header
• Fixed index reference for hash
• Removed indirection of CDDL type definition for filesystem-item
• Fixed quantity of resource and process
• Updated resource-collection
• Renamed socket name in software-meta to be consistent in naming
• Aligned excerpt examples in I-D text with full CDDL
• Fixed titles where title was referring to group instead of map
• Added missing date in SEMVER
• Fixed root cardinality for file and directory, etc.
• Transformed path-elements-entry from map to group for re-usability
• Scrubbed IANA Section
• Removed redundant supplemental rule
• Aligned discrepancy with ISO spec.
• Addressed comments on typos.
• Fixed kramdown nits and BCP reference.
• Addressed comments from WGLC reviewers.

Changes in version 12:

• Addressed a bunch of minor editorial issues based on WGLC feedback.
• Added text about the use of UTF-8 in CoSWID.
• Adjusted tag-id to allow for a UUID to be provided as a bstr.
• Cleaned up descriptions of index ranges throughout the document, removing discussion of 8 bit, 16 bit, etc.
• Adjusted discussion of private use ranges to use negative integer values and to be more clear throughout the document.
• Added discussion around resolving overlapping value spaces for version schemes.
• Added a set of expert review criteria for new IANA registries created by this document.
• Added new registrations for the "swid" and "swidpath" URI schemes, and for using CoSWID with SWIMA.

Changes from version 03 to version 11:

• Reduced representation complexity of the media-entry type and removed the Section describing the older data structure.
• Added more signature schemes from COSE
• Included a minimal required set of normative language
• Reordering of attribute name to integer label by priority according to semantics.
• Added an IANA registry for CoSWID items supporting future extension.
• Cleaned up IANA registrations, fixing some inconsistencies in the table labels.
• Added additional CDDL sockets for resource collection entries providing for additional extension points to address future SWID/CoSWID extensions.
• Updated Section on extension points to address new CDDL sockets and to reference the new IANA registry for items.
• Removed unused references and added new references to address placeholder comments.
• Added table with semantics for the link ownership item.
• Clarified language, made term use more consistent, fixed references, and replacing lowercase RFC2119 keywords.

Changes from version 02 to version 03:

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

Changes from version 01 to version 02:

• Enforced a more strict separation between the core CoSWID definition and additional usage by moving content to corresponding appendices.
• Removed artifacts inherited from the reference schema provided by ISO (e.g., NMTOKEN(S))
• Simplified the core data definition by removing group and type choices where possible
• Minor reordering of map members
• Added a first extension point to address requested flexibility for extensions beyond the any-element

Changes from version 00 to version 01:

• Ambiguity between evidence and payload eliminated by introducing explicit members (while still
• allowing for "empty" SWID tags)
• Added a relatively restrictive COSE envelope using cose_sign1 to define signed CoSWID (single signer only, at the moment)
• 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:

• Removed redundant any-attributes originating from the ISO-19770-2:2015 XML schema definition
• Fixed broken multi-map members
• Introduced a more restrictive item (any-element-map) to represent custom maps, increased restriction on types for the any-attribute, accordingly
• Fixed X.1520 reference
• Minor type changes of some attributes (e.g., NMTOKENS)
• Added semantic differentiation of various name types (e,g. fs-name)

Changes from version 06 to version 07:

• Added type choices/enumerations based on textual definitions in 19770-2:2015
• Added value registry request
• Added media type registration request
• Added content format registration request
• Added CBOR tag registration request
• Removed RIM appendix to be addressed in complementary draft
• Removed CWT appendix
• Flagged firmware resource collection appendix for revision
• Made use of terminology more consistent
• Better defined use of extension points in the CDDL
• Added definitions for indexed values
• Added IANA registry for Link use indexed values

Changes from version 05 to version 06:

• Improved quantities
• Included proposals for implicit enumerations that were NMTOKENS
• Added extension points
• Improved exemplary firmware-resource extension

Changes from version 04 to version 05:

• Clarified language around SWID and CoSWID to make more consistent use of these terms.
• Added language describing CBOR optimizations for single vs. arrays in the model front matter.
• Fixed a number of grammatical, spelling, and wording issues.
• Documented extension points that use CDDL sockets.
• Converted IANA registration tables to markdown tables, reserving the 0 value for use when a value is not known.
• Updated a number of references to their current versions.

Changes from version 03 to version 04:

• Re-index label values in the CDDL.
• Added a Section describing the CoSWID model in detail.
• Created IANA registries for entity-role and version-scheme

Changes from version 02 to version 03:

• Updated CDDL to allow for a choice between a payload or evidence
• Re-index label values in the CDDL.
• Added item definitions
• Updated references for COSE, CBOR Web Token, and CDDL.

Changes from version 01 to version 02:

• Added extensions for Firmware and CoSWID use as Reference Integrity Measurements (CoSWID RIM)
• Changes meta handling in CDDL from use of an explicit use of items to a more flexible unconstrained collection of items.
• Added Sections discussing use of COSE Signatures and CBOR Web Tokens

Changes from version 00 to version 01:

• Added CWT usage for absolute SWID paths on a device
• Fixed cardinality of type-choices including arrays
• Included first iteration of firmware resource-collection

References Normative References Many protocols make use of points of extensibility that use constants to identify various protocol parameters. To ensure that the values in these fields do not have conflicting uses and to promote interoperability, their allocations are often coordinated by a central record keeper. For IETF protocols, that role is filled by the Internet Assigned Numbers Authority (IANA). To make assignments in a given registry prudently, guidance describing the conditions under which new values should be assigned, as well as when and how modifications to existing values can be made, is needed. This document defines a framework for the documentation of these guidelines by specification authors, in order to assure that the provided guidance for the IANA Considerations is clear and addresses the various issues that are likely in the operation of a registry. This is the third edition of this document; it obsoletes RFC 5226. Historically, designers and implementers of application protocols have often distinguished between standardized and unstandardized parameters by prefixing the names of unstandardized parameters with the string "X-" or similar constructs. In practice, that convention causes more problems than it solves. Therefore, this document deprecates the convention for newly defined parameters with textual (as opposed to numerical) names in application protocols. This memo documents an Internet Best Current Practice. ISO/IEC 10646-1 defines a large character set called the Universal Character Set (UCS) which encompasses most of the world's writing systems. The originally proposed encodings of the UCS, however, were not compatible with many current applications and protocols, and this has led to the development of UTF-8, the object of this memo. UTF-8 has the characteristic of preserving the full US-ASCII range, providing compatibility with file systems, parsers and other software that rely on US-ASCII values but are transparent to other values. This memo obsoletes and replaces RFC 2279. A Uniform Resource Identifier (URI) is a compact sequence of characters that identifies an abstract or physical resource. This specification defines the generic URI syntax and a process for resolving URI references that might be in relative form, along with guidelines and security considerations for the use of URIs on the Internet. The URI syntax defines a grammar that is a superset of all valid URIs, allowing an implementation to parse the common components of a URI reference without knowing the scheme-specific requirements of every possible identifier. This specification does not define a generative grammar for URIs; that task is performed by the individual specifications of each URI scheme. [STANDARDS-TRACK] The Internet today is in need of a standardized form for the transmission of internationalized "text" information, paralleling the specifications for the use of ASCII that date from the early days of the ARPANET. This document specifies that format, using UTF-8 with normalization and specific line-ending sequences. [STANDARDS-TRACK] Internet technical specifications often need to define a formal syntax. Over the years, a modified version of Backus-Naur Form (BNF), called Augmented BNF (ABNF), has been popular among many Internet specifications. The current specification documents ABNF. It balances compactness and simplicity with reasonable representational power. The differences between standard BNF and ABNF involve naming rules, repetition, alternatives, order-independence, and value ranges. This specification also supplies additional rule definitions and encoding for a core lexical analyzer of the type common to several Internet specifications. [STANDARDS-TRACK] This document describes the structure, content, construction, and semantics of language tags for use in cases where it is desirable to indicate the language used in an information object. It also describes how to register values for use in language tags and the creation of user-defined extensions for private interchange. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. This document is one of a collection that, together, describe the protocol and usage context for a revision of Internationalized Domain Names for Applications (IDNA), superseding the earlier version. It describes the document collection and provides definitions and other material that are common to the set. [STANDARDS-TRACK] The Concise Binary Object Representation (CBOR) is a data format whose design goals include the possibility of extremely small code size, fairly small message size, and extensibility without the need for version negotiation. These design goals make it different from earlier binary serializations such as ASN.1 and MessagePack. This document obsoletes RFC 7049, providing editorial improvements, new details, and errata fixes while keeping full compatibility with the interchange format of RFC 7049. It does not create a new version of the format. The Constrained Application Protocol (CoAP) is a specialized web transfer protocol for use with constrained nodes and constrained (e.g., low-power, lossy) networks. The nodes often have 8-bit microcontrollers with small amounts of ROM and RAM, while constrained networks such as IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs) often have high packet error rates and a typical throughput of 10s of kbit/s. The protocol is designed for machine- to-machine (M2M) applications such as smart energy and building automation. CoAP provides a request/response interaction model between application endpoints, supports built-in discovery of services and resources, and includes key concepts of the Web such as URIs and Internet media types. CoAP is designed to easily interface with HTTP for integration with the Web while meeting specialized requirements such as multicast support, very low overhead, and simplicity for constrained environments. August Cellars Concise Binary Object Representation (CBOR) is a data format designed for small code size and small message size. There is a need to be able to define basic security services for this data format. This document defines the CBOR Object Signing and Encryption (COSE) protocol. This specification describes how to create and process signatures, message authentication codes, and encryption using CBOR for serialization. This specification additionally describes how to represent cryptographic keys using CBOR. This document, along with RFC 9053, obsoletes RFC 8152. This document extends "PA-TNC: A Posture Attribute (PA) Protocol Compatible with Trusted Network Connect (TNC)" (RFC 5792) by providing specific attributes and message exchanges to allow endpoints to report their installed software inventory information to a NEA Server, as defined in "Network Endpoint Assessment (NEA): Overview and Requirements" (RFC 5209). This specification defines a model for the relationships between resources on the Web ("links") and the type of those relationships ("link relation types"). It also defines the serialisation of such links in HTTP headers with the Link header field. This document proposes a notational convention to express Concise Binary Object Representation (CBOR) data structures (RFC 7049). Its main goal is to provide an easy and unambiguous way to express structures for protocol messages and data formats that use CBOR or JSON. August Cellars Vigil Security, LLC Concise Binary Object Representation (CBOR) is a data format designed for small code size and small message size. CBOR Object Signing and Encryption (COSE) defines a set of security services for CBOR. This document defines a countersignature algorithm along with the needed header parameters and CBOR tags for COSE. This document updates RFC 9052. IANA In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. IANA IANA IANA IANA Informative References There has been ongoing confusion about the differences between Information Models and Data Models for defining managed objects in network management. This document explains the differences between these terms by analyzing how existing network management model specifications (from the IETF and other bodies such as the International Telecommunication Union (ITU) or the Distributed Management Task Force (DMTF)) fit into the universe of Information Models and Data Models. This memo documents the main results of the 8th workshop of the Network Management Research Group (NMRG) of the Internet Research Task Force (IRTF) hosted by the University of Texas at Austin. This memo provides information for the Internet community. This specification defines a Uniform Resource Name namespace for UUIDs (Universally Unique IDentifier), also known as GUIDs (Globally Unique IDentifier). A UUID is 128 bits long, and can guarantee uniqueness across space and time. UUIDs were originally used in the Apollo Network Computing System and later in the Open Software Foundation\'s (OSF) Distributed Computing Environment (DCE), and then in Microsoft Windows platforms. This specification is derived from the DCE specification with the kind permission of the OSF (now known as The Open Group). Information from earlier versions of the DCE specification have been incorporated into this document. [STANDARDS-TRACK] This document defines a resource-oriented approach for security automation information publication, discovery, and sharing. Using this approach, producers may publish, share, and exchange representations of software descriptors, security incidents, attack indicators, software vulnerabilities, configuration checklists, and other security automation information as web-addressable resources. Furthermore, consumers and other stakeholders may access and search this security information as needed, establishing a rapid and on-demand information exchange network for restricted internal use or public access repositories. This specification extends the Atom Publishing Protocol and Atom Syndication Format to transport and share security automation resource representations. This memo specifies a component-based architecture for Manufacturer Usage Descriptions (MUDs). The goal of MUD is to provide a means for end devices to signal to the network what sort of access and network functionality they require to properly function. The initial focus is on access control. Later work can delve into other aspects. This memo specifies two YANG modules, IPv4 and IPv6 DHCP options, a Link Layer Discovery Protocol (LLDP) TLV, a URL, an X.509 certificate extension, and a means to sign and verify the descriptions. In network protocol exchanges, it is often useful for one end of a communication to know whether the other end is in an intended operating state. This document provides an architectural overview of the entities involved that make such tests possible through the process of generating, conveying, and evaluating evidentiary Claims. It provides a model that is neutral toward processor architectures, the content of Claims, and protocols. National Institute for Standards and Technology The MITRE Corporation G2, Inc G2, Inc

Acknowledgments This document draws heavily on the concepts defined in the ISO/IEC 19770-2:2015 specification. The authors of this document are grateful for the prior work of the 19770-2 contributors. We are also grateful for the careful reviews provided by the IESG reviewers. Special thanks go to Benjamin Kaduk.

Contributors Universität Bremen TZI

Postfach 330440 Bremen D-28359 Germany +49-421-218-63921 cabo@tzi.org

Carsten Bormann contributed to the CDDL specifications and the IANA considerations.