SACM Working Group H. Birkholz
Internet-Draft Fraunhofer SIT
Intended status: Standards Track J. Fitzgerald-McKay
Expires: July 8, 2018 Department of Defense
C. Schmidt
The MITRE Corporation
D. Waltermire
January 04, 2018

Concise Software Identifiers


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

Status of This Memo

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

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This Internet-Draft will expire on July 8, 2018.

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Table of Contents

1. Introduction

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

SWID tags, as defined in ISO-19770-2:2015 [SWID], provide a standardized format for a record that identifies and describes a specific release of a software product. Different software products, and even different releases of a particular software product, each have a different SWID tag record associated with them. In addition to defining the format of these records, ISO-19770-2:2015 defines requirements concerning the SWID tag life-cycle. Specifically, when a software product is installed on an endpoint, that product’s SWID tag is also installed. Likewise, when the product is uninstalled or replaced, the SWID tag is deleted or replaced, as appropriate. As a result, ISO-19770-2:2015 describes a system wherein there is a correspondence between the set of installed software products on an endpoint, and the presence on that endpoint of the SWID tags corresponding to those products.

SWID tags are meant to be flexible and able to express a broad set of metadata about a software product. Moreover, there are multiple types of SWID tags, each providing different types of information. For example, a “corpus tag” is used to describe an application’s installation image on an installation media, while a “patch tag” is meant to describe a patch that modifies some other application. While there are very few required fields in SWID tags, there are many optional fields that support different uses of these different types of tags. While a SWID tag that consisted only of required fields could be a few hundred bytes in size, a tag containing many of the optional fields could be many orders of magnitude larger.

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

Real-world instances of SWID tags can be fairly large, and the communication of SWID tags in use-applications such as those described earlier can cause a large amount of data to be transported. This can be larger than acceptable for constrained devices and networks. CoSWID tags significantly reduce the amount of data transported as compared to a typical SWID tag. This reduction is enable through the use of CBOR, which maps human-readable labels of that content to more concise integer labels (indices). This allows SWID tags to be part of an enterprise security solution for a wider range of endpoints and environments.

1.1. Concise SWID Extensions

This document specifies a standard equivalent to the ISO-19770-2:2015 standard. The corresponding CoSWID data definition includes two kinds of augmentation.

1.2. Requirements Notation

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “NOT RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119, BCP 14 [RFC2119].

2. Concise SWID Data Definition

The following is a CDDL representation of the ISO-19770-2:2015 [SWID] XML schema definition of SWID tags. This representation includes every SWID tag fields and attribute and thus supports all SWID tag use cases. The CamelCase notation used in the XML schema definition is changed to a hyphen-separated notation (e.g. ResourceCollection is named resource-collection in the CoSWID data definition). This deviation from the original notation used in the XML representation reduces ambiguity when referencing certain attributes in corresponding textual descriptions. An attribute referred by its name in CamelCase notation explicitly relates to XML SWID tags, an attribute referred by its name in hyphen-separated notation explicitly relates to CoSWID tags. This approach simplifies the composition of further work that reference both XML SWID and CoSWID documents.

Human-readable names of members in the CDDL data definition are mapped to integer indices via a block of rules at the bottom of the definition. The 66 character strings of the SWID vocabulary that would have to be stored or transported in full if using the original vocabulary are replaced.

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

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

concise-software-identity = {
  ? entity-entry,
  ? payload-xor-evidence-entry,
  ? link-entry,
  ? software-meta-entry,
;  ? payload-entry,
  ? any-element-entry,
  ? corpus,
  ? patch,
  ? media,
  ? supplemental,
  ? tag-version,
  ? software-version,
  ? version-scheme,

any-uri = text
label = text / int

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

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

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

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

file = {
  ? size,
  ? file-version,
  ? file-hash,

filesystem-item = (
  ? key,
  ? location,
  ? root,

directory = {

process = {
  ? pid,

resource = {

entity = {
  ? reg-id,
  ? thumbprint,

evidence = {
  ? date,
  ? device-id,

link = {
  ? artifact,
  ? media-type,
  ? ownership,
  ? type,
  ? use,

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

payload = {

payload-xor-evidence-entry = ((3: evidence) // (6: payload))
tag-id = (0: text)
swid-name = (1: text)
entity-entry = (2: entity / [ 2* entity ])
evidence-entry = (3: evidence)
link-entry = (4: link / [ 2* link ])
software-meta-entry = (5: software-meta / [ 2* software-meta ])
payload-entry = (6: payload)
any-element-entry = (7: any-element-map / [ 2* any-element-map ])
corpus = (8: bool)
patch = (9: bool)
media = (10: text)
supplemental = (11: bool)
tag-version = (12: integer)
software-version = (13: text)
version-scheme = (14: text)
lang = (15: text)
directory-entry = (16: directory / [ 2* directory ])
file-entry = (17: file / [ 2* file ])
process-entry = (18: process / [ 2* process ])
resource-entry = (19: resource / [ 2* resource ])
size = (20: integer)
file-version = (21: text)
key = (22: bool)
location = (23: text)
fs-name = (24: text)
root = (25: text)
path-elements = (26: { * file-entry,
                       * directory-entry,
process-name = (27: text)
pid = (28: integer)
type = (29: text)
extended-data = (30: any-element-map / [ 2* any-element-map ])
entity-name = (31: text)
reg-id = (32: any-uri)
role = (33: text / [2* text])
thumbprint = (34: text)
date = (35: time)
device-id = (36: text)
artifact = (37: text)
href = (38: any-uri)
ownership = (39: "shared" / "private" / "abandon")
rel = (40: text)
media-type = (41: text)
use = (42: "optional" / "required" / "recommended")
activation-status = (43: text)
channel-type = (44: text)
colloquial-version = (45: text)
description = (46: text)
edition = (47: text)
entitlement-data-required = (48: bool)
entitlement-key = (49: text)
generator = (50: text)
persistent-id = (51: text)
product = (52: text)
product-family = (53: text)
revision = (54: text)
summary = (55: text)
unspsc-code = (56: text)
unspsc-version = (57: text)
file-hash = (58: [ hash-alg-id: int,
                   hash-value: bstr,

3. Description of the SWID Attribute Vocabulary Definition

Yet to be written still…

4. IANA Considerations

This document will include requests to IANA:

5. Security Considerations

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

A signed SWID tag whose signature is intact can be relied upon to be unchanged since it was signed. If the SWID tag was created by the software author, this generally means that it has undergone no change since the software application with which the tag is associated was installed. By implication, this means that the signed tag reflects the software author’s understanding of the details of that software product. This can be useful assurance when the information in the tag needs to be trusted, such as when the tag is being used to convey golden measurements. By contrast, the data contained in unsigned tags cannot be trusted to be unmodified.

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

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

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

6. Acknowledgements

7. Change Log

Changes from version 00 to version 01:

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

Changes from version 00 to version 01:

Changes from version 01 to version 02:

8. Contributors

9. References

9.1. Normative References

[I-D.ietf-ace-cbor-web-token] Jones, M., Wahlstroem, E., Erdtman, S. and H. Tschofenig, "CBOR Web Token (CWT)", Internet-Draft draft-ietf-ace-cbor-web-token-10, December 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC4108] Housley, R., "Using Cryptographic Message Syntax (CMS) to Protect Firmware Packages", RFC 4108, DOI 10.17487/RFC4108, August 2005.
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2", FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, October 2013.
[RFC7228] Bormann, C., Ersue, M. and A. Keranen, "Terminology for Constrained-Node Networks", RFC 7228, DOI 10.17487/RFC7228, May 2014.
[RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)", RFC 8152, DOI 10.17487/RFC8152, July 2017.
[SAM] "Information technology - Software asset management - Part 5: Overview and vocabulary", ISO/IEC 19770-5:2013, November 2013.
[SWID] "Information technology - Software asset management - Part 2: Software identification tag'", ISO/IEC 19770-2:2015, October 2015.
[X.1520] "Recommendation ITU-T X.1520 (2014), Common vulnerabilities and exposures", April 2011.

9.2. Informative References

[I-D.banghart-sacm-rolie-softwaredescriptor] Waltermire, D. and S. Banghart, "Definition of the ROLIE Software Descriptor Extension", Internet-Draft draft-banghart-sacm-rolie-softwaredescriptor-01, May 2017.
[I-D.birkholz-tuda] Fuchs, A., Birkholz, H., McDonald, I. and C. Bormann, "Time-Based Uni-Directional Attestation", Internet-Draft draft-birkholz-tuda-04, March 2017.
[I-D.ietf-cbor-cddl] Birkholz, H., Vigano, C. and C. Bormann, "Concise data definition language (CDDL): a notational convention to express CBOR data structures", Internet-Draft draft-ietf-cbor-cddl-00, July 2017.
[I-D.ietf-sacm-terminology] Birkholz, H., Lu, J., Strassner, J., Cam-Winget, N. and A. Montville, "Security Automation and Continuous Monitoring (SACM) Terminology", Internet-Draft draft-ietf-sacm-terminology-14, December 2017.

Appendix A. Explicit file-hash Type Used in Concise SWID Tags (label 56)

CoSWID add explicit support for the representation of file-hashes using algorithms that are registered at the Named Information Hash Algorithm Registry via the file-hash member (label 56).

file-hash = (56: [ hash-alg-id: int, hash-value: bstr ] )

The number used as a value for hash-alg-id MUST refer the ID in the Named Information Hash Algorithm table; other hash algorithms MUST NOT be used. The hash-value MUST represent the raw hash value of the file-entry the file-hash type is included in.

Appendix B. CoSWID Attributes for Firmware (label 57)

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

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

To address the specific characteristics of firmware, the extension point $$resource-extension is used to allow for an additional type of resource description—firmware-entry—thereby increasing the self-descriptiveness and flexibility of CoSWID. The optional use of the extension point $$resource-extension in respect to firmware MUST adhere to the following CDDL data definition.

$$resource-extension //= (firmware-entry,)

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

firmware-entry = (57: firmware / [ 2* firmware ])
firmware-hash = (58: [ hash-alg-id: int,
                      hash-value: bstr,
firmware-name = (59 : text)
firmware-version = (60 : text / int)
component-index = (61 : int)
model-label = (62: text / int)
block-device-identifier = (63 : text / int)
firmware-package = (64: bstr)
firmware-package-identifier = (65: text)
target-hardware-identifier = (66: text)
dependency = (67: { ? firmware-name,
                    ? firmware-version,
                    ? firmware-package-identifier,

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

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

Appendix C. Signed Concise SWID Tags using COSE

SWID tags, as defined in the ISO-19770-2:2015 XML schema, can include cryptographic signatures to protect the integrity of the SWID tag. In general, tags are signed by the tag creator (typically, although not exclusively, the vendor of the software product 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 measurments for files.

The ISO-19770-2:2015 XML schema uses XML DSIG to support cryptographic signatures. CoSWID tags require a different signature scheme than this. COSE (CBOR Object Signing and Encryption) provides the required mechanism [RFC8152]. Concise SWID can be wrapped in a COSE Single Signer Data Object (cose-sign1) that contains a single signature. The following CDDL defines a more restrictive subset of header attributes allowed by COSE tailored to suit the requirements of Concise SWID.

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

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

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

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

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

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

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

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

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

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

Appendix E. CBOR Web Token for Concise SWID Tags

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


Appendix F. Group Definitions

These groups are intermediate CDDL data definitions that are reused in several items in the CoSWID CDDL data definition.

Appendix G. Item Definitions

This Appendix includes the description of every primitive and non-primitive type the concise-software-identifier is composed of. Every integer label included at the end of the CDDL data definition is addressed in this section.

  1. tag-id: An identifier uniquely referencing a (composite) software component. The tag identifier is intended to be globally unique. There are no strict guidelines on how this identifier is structured, but examples include a 16 byte GUID (e.g. class 4 UUID).
  2. swid-name: This item provides the software component name as it would typically be referenced. For example, what would be seen in the add/remove dialog on a Windows device, or what is specified as the name of a packaged software product or a patch identifier name on a Linux device.
  3. entity: Specifies the organizations related to the software component referenced by this CoSWID tag.
  4. evidence: This item is used to provide results from a scan of a system where software that does not have a CoSWID tag is discovered. This information is not provided by the software-creator, and is instead created when a system is being scanned and the evidence for why software is believed to be installed on the device is provided in the evidence item.
  5. link: A reference to any another item (can include details that are related to the CoSWID tag such as details on where specific resources can be found, e.g. vulnerability database associations, ROLIE feeds, MUD files, etc). This is modeled directly to match the HTML [LINK] element; it is critical for streamlining software discovery scenarios to ensure their consistency.
  6. software-meta: An open-ended collection of key/value data related to this CoSWID. The attributes included in this Element are predefined attributes to ensure common usage across the industry. The schema allows for any additional attribute to be included in a CoSWID tag, though it is recommended that industry norms for new attributes are defined and followed to the degree possible.
  7. payload: The items that may be installed on a system entity when the software component is installed. Note that payload may be a superset of the items installed and - depending on optimization mechanisms in respect to that system entity - may or may not include every item that could be created or executed on the corresponding system entitiy when software components are installed. In general, payload will be used to indicate the files that may be installed with a software component. Therefore payload will often be a superset of those files (i.e. if a particular optional sub-component is not installed, the files associated with that software component may be included in payload, but not installed in the system entity).
  8. any-element: A default map that can contain arbitrary map members and even nested maps (which would be also any-elements). In essence, the any-element allows items not defined in this CDDL data definition to be included in a Concise Software Identifier.
  9. corpus: Set to true, if this attribute specifies that this SWID tag is a collection of information that describes the pre-installation data of software component.
  10. patch: A set of files that is intended to modify an existing set of files (including configuration files, scripts and corresponding environment variables that are create by the OS for the runtime environment) that composes a software component. A software component patch does neither alter the version number (see 13) nor the release details (descriptive english text, see 44) of a software components. [revision 52?]. If a Concise SWID tag is a patch, it MUST contain the patch item and its value MUST be set to true. It is recommended but not required to include a rel(ation) item in a patch CoSWID. If a CoSWID includes a patch member, but not a rel member, it is implied that it SHOULD be installed independently of any other CoSWID tag document – even if an effective but not explicit relationship exists.
  11. media: This text value is a hint to the tag consumer to understand what this SWID tag applies to. This item can also be included in the link item to represent a attributes defined by the W3C Media Queries Recommendation (see A hint to the consumer of the link to what the target item is applicable for.
  12. supplemental: Specifies that this tag provides supplemental tag data that can be merged with primary tag data to create a complete record of the software information. Supplemental tags will often be provided at install time and may be provided by different entities (such as the tag consumer, or a Value Added Reseller).
  13. tag-version: This item indicates if a specific release of a software component has more than one tag that can represent that specific release. This may be the case if a CoSWID tag producer creates and releases an incorrect tag that they subsequently want to fix, but with no underlying changes to the product the CoSWID tag represents. This could happen if, for example, a patch is distributed that has a link reference that does not cover all the various software releases it can patch. A newer CoSWID tag for that patch can be generated and the tag-version value incremented to indicate that the data is updated.
  14. software-version: Underlying development version for the software component.
  15. version-scheme: Scheme used for the version number. Valid enumerations are : * alphanumeric: strictly a string, sorting alphanumerically * decimal: a floating point number (i.e., 1.25 is less than 1.3 ) * multipartnumeric: numbers separated via dots, where the numbers are * interpreted as integers (ie, 1.2.3 , , This string * convention is similar to OIDs. * multipartnumeric+suffix: numbers separated via dots, where the numbers are * interpreted as integers with an additional string suffix (e.g., 1.2.3a). * semver: a string as defined by the spec [FiXME: reference] * unknown: the last resort choice, no attempt should be made to order these
  16. lang: An RFC5646 conferment language tag or corresponding IANA index integer.
  17. directory: A directory item allows one or more directories to be defined in the file structure.
  18. file: A file element that allows one or more files to be specified for a given location.
  19. process: Provides process (software component in execution) information for data that will show up in a devices process table.
  20. resource: A set of items that can be used to provide arbitrary resource information about an application installed on a system entity, or evidence collected from a system entity.
  21. size: The file size in bytes of the file.
  22. file-version The file version.
  23. key: Files that are considered important or required for the use of a software component. Typical key files would be those which, if not available on a system entity, would cause the software component not to execute or function properly. Key files will typically be used to validate that a software component referenced by the CoSWID tag document is actually installed on a specific system entity.
  24. location: The directory or location where a file was found or can expected to be located. This text-string is intended to include the filename itself. This SHOULD be the relative path represented by the root item.
  25. fs-name: The file name or directory name without any path characters.
  26. root: A system-specific root folder that the location item is an offset from. If this is not specified the assumption is the root is the same folder as the location of the CoSWID tag. The text-string value represents a path expression relative to the CoSWID tag document location in the (composite) file-system hierarchy.
  27. path-elements: Provides the ability to apply a directory structure to the path expressions for files defined in a payload or evidence item.
  28. process-name: The process name as it will be found in the system entity’s process table.
  29. pid: The process ID for the process in execution that can be included in the process item as part of an evidence tag.
  30. type: The type of resource represented via a text-string (typically, registry-key, port or root-uri)
  31. extended-data: An open-ended collection of elements that can be used to attach arbitrary metadata to an entity item.
  32. entity-name: The text-string name of the organization claiming a particular role in the CoSWID tag.
  33. reg-id: The registration id is intended to uniquely identify a naming authority in a given scope (e.g. global, organization, vendor, customer, administrative domain, etc.) that is implied by the referenced naming authority. The value of an registration ID MUST be a RFC 3986 URI. The scope SHOULD be the scope of an organization. In a given scope, the registration id MUST be used consistently.
  34. role: The relationship between this organization and this tag. The role of tag creator is required for every CoSWID tag. The role of an entity may include any role value, but the per-defined roles include: “aggregator”, “distributor”, “licensor”, “software-creator”, “tag-creator”. The enumerations of this will include a request to IANA in order to be reference-able via an integer index.
  35. thumbprint: This value provides a hexadecimal string that contains a hash (i.e. the thumbprint) of the signing entities certificate [s] [FIXME: this requires the same structure as file-hash?].
  36. date: The sate and time evidence represented by an evidence item was gathered.
  37. device-id: A text-string identifier for a device evidence was gathered from.
  38. artifact: For installation media (rel=”installation-media”) - dictates the canonical name for the file. Items with the same artifact name should be considered mirrors of each other (so download from wherever works).
  39. href: The link to the item being referenced. The href can point to several different things, and can be any of the following: * a relative uri (no scheme), which is interpreted depending on context (for example, “./folder/supplemental.coswid”) * a physical file location with any system-acceptable URI scheme (e.g., file:// http:// https:// ftp://) * an URI with “coswid:” as the scheme, which refers to another CoSWID by tag-id. This URI would need to be resolved in the context of the system by software that can lookup other CoSWID tags (for example, * “coswid:2df9de35-0aff-4a86-ace6-f7dddd1ade4c”). an URI with “swidpath:” as the scheme, which refers to another CoSIWD via an XPATH query. This URI would need to be resolved in the context of the system entity via dedicated software components that can lookup other CoSWID tags and select the appropriate tag based on an XPATH query. Examples include: * swidpath://SoftwareIdentity[Entity/@regid=’’] would * retrieve all CoSWID tags that include an entity where the regid was * “Contoso”. * swidpath://SoftwareIdentity[Meta/@persistentId=’b0c55172-38e9-4e36-be86-92206ad8eddb’] * would retrieve CoSWID tags that matched the persistent-id. See XPATH query standard : [FIXME: Concise XPATH representation is covered in the YANG-CBOR I-D]
  40. ownership: Determines the relative strength of ownership of the software components. Valid enumerations are: abandon, private, shared
  41. rel: The relationship between this CoSWID and the target file. Relationships can be identified by referencing the IANA registration library:
  42. media-type: The IANA MediaType for the target file; this provides the consumer with intelligence of what to expect. See for more details on link type.
  43. use: Determines if the target software is a hard requirement or not. Valid enumerations are: required, recommended, optional,
  44. activation-status: Identification of the activation status of this software title (e.g. Trial, Serialized, Licensed, Unlicensed, etc). Typically, this is used in supplemental tags.
  45. channel-type: Provides information on which channel this particular software was targeted for (e.g. Volume, Retail, OEM, Academic, etc). Typically used in supplemental tags.
  46. colloquial-version: The informal or colloquial version of the product (i.e. 2013). Note that this version may be the same through multiple releases of a software product where the version specified in entity is much more specific and will change for each software release. Note that this representation of version is typically used to identify a group of specific software releases that are part of the same release/support infrastructure (i.e. Fabrikam Office 2013). This version is used for string comparisons only and is not compared to be an earlier or later release (that is done via the entity version [FIXME: consistency).
  47. description: A longer, detailed description of the software. This description can be multiple sentences (differentiated from summary, which is a very short, one-sentence description).
  48. edition: The variation of the product (Extended, Enterprise, Professional, Standard etc).
  49. entitlement-data-required: An indicator to determine if there should be accompanying proof of entitlement when a software license reconciliation is completed.
  50. entitlement-key: A vendor-specific textual key that can be used to reconcile the validity of an entitlement. (e.g. serial number, product or license key).
  51. generator: The name of the software tool that created a CoSWID tag. This item is typically used if tags are created on the fly or via a catalog-based analysis for data found on a computing device.
  52. persistent-id: A GUID used to represent products installed where the product are related, but may be different versions. For example, an “upgradeCode” (see as an reference for this example).
  53. product: The base name of the product (e.g. [FIXME: what are appropriate examples?].
  54. product-family: The overall product family this software belongs to. Product family is not used to identify that a product is part of a suite, but is instead used when a set of products that are all related may be installed on multiple different devices. For example, an enterprise backup system may consist of a backup services, multiple different backup services that support mail services, databases and ERP systems, as well as individual software components that backup client system entities. In such an usage scenario, all software components that are part of the backup system would have the same product-family name so they can be grouped together in respect to reporting systems.
  55. revision: The informal or colloquial representation of the sub-version of the given product (ie, SP1, R2, RC1, Beta 2, etc). Note that the version will provide very exact version details, the revision is intended for use in environments where reporting on the informal or colloquial representation of the software is important (for example, if for a certain business process, an organization recognizes that it must have, for example “ServicePack 1” or later of a specific product installed on all devices, they can use the revision data value to quickly identify any devices that do not meet this requirement). Depending on how a software organizations distributes revisions, this value could be specified in a primary (if distributed as an upgrade) or supplemental (if distributed as a patch) CoSWID tag.
  56. summary: A short (one-sentence) description of the software.
  57. unspsc-code: An 8 digit code that provides UNSPSC classification of the software product this SWID tag identifies. For more information see,
  58. unspsc-version: The version of the UNSPSC code used to define the UNSPSC code value. For more information see,

Authors' Addresses

Henk Birkholz Fraunhofer SIT Rheinstrasse 75 Darmstadt, 64295 Germany EMail:
Jessica Fitzgerald-McKay Department of Defense 9800 Savage Road Ft. Meade, Maryland USA EMail:
Charles Schmidt The MITRE Corporation 202 Burlington Road Bedford, Maryland 01730 USA EMail:
David Waltermire National Institute of Standards and Technology 100 Bureau Drive Gaithersburg, Maryland 20877 USA EMail: