Internet DRAFT - draft-lundblade-rats-eat-media-type
draft-lundblade-rats-eat-media-type
RATS L. Lundblade
Internet-Draft Security Theory LLC
Intended status: Standards Track H. Birkholz
Expires: 27 November 2022 Fraunhofer SIT
T. Fossati
arm
26 May 2022
EAT Media Types
draft-lundblade-rats-eat-media-type-00
Abstract
Payloads used in Remote Attestation Procedures may require an
associated media type for their conveyance, for example when used in
RESTful APIs.
This memo defines media types to be used for Entity Attestation
Tokens (EAT).
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the Remote ATtestation
ProcedureS Working Group mailing list (rats@ietf.org), which is
archived at https://mailarchive.ietf.org/arch/browse/rats/.
Source for this draft and an issue tracker can be found at
https://github.com/thomas-fossati/draft-eat-mt.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 27 November 2022.
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Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. EAT Types . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. A Media Type Parameter for EAT Profiles . . . . . . . . . . . 4
4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6.1. Media Types . . . . . . . . . . . . . . . . . . . . . . . 6
6.2. application/eat-cwt Registration . . . . . . . . . . . . 6
6.3. application/eat-jwt Registration . . . . . . . . . . . . 7
6.4. application/eat-deb+cbor Registration . . . . . . . . . . 7
6.5. application/eat-deb+json Registration . . . . . . . . . . 8
6.6. application/eat-ucs+cbor Registration . . . . . . . . . . 8
6.7. application/eat-ucs+json Registration . . . . . . . . . . 9
6.8. Content-Format . . . . . . . . . . . . . . . . . . . . . 9
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . 10
7.2. Informative References . . . . . . . . . . . . . . . . . 11
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
Payloads used in Remote Attestation Procedures [RATS-Arch] may
require an associated media type for their conveyance, for example
when used in RESTful APIs (Figure 1).
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.----. .----------. .----------.
| RP | | Attester | | Verifier |
'-+--' '----+-----' '-----+----'
| | POST /verify |
| | EAT(Evidence) |
| +--------------------------->|
| | 200 OK |
| | EAT(Attestation Results) |
| |<---------------------------+
| POST /auth | |
| EAT(Attestation Results) | |
|<---------------------------+ |
| 201 Created | |
+--------------------------->| |
| | |
| | |
Figure 1: Conveying RATS conceptual messages in REST APIs using EAT
This memo defines media types to be used for Entity Attestation Token
(EAT) [EAT] payloads independently of the RATS Conceptual Message in
which they manifest themselves.
1.1. Requirements Language
This document uses the terms and concepts defined in [RATS-Arch].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. EAT Types
Figure 2 illustrates the six EAT wire formats and how they relate to
each other. [EAT] defines four of them (CWT, JWT and DEB in its JSON
and CBOR flavours), whilst [UCCS] defines the remaining two: UCCS and
UJCS.
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.-----.
.----+ UJCS |<-------------------------.
| '-----' |
| |
| .-----. |
+-----+ UCCS |<-----------------------. |
| '-----' | |
| | |
| .------. | |
+-----+ JWT |<------. | |
| '------' .--+---. | |
| | Crypto |<------. | |
| .------. '--+---' | | |
+-----+ CWT |<------' | | |
| '------' .---+-+-+----.
| | Claims-Set +--.
| .------. '---+---+----' |
+-----+ DEB-J |<------. | ^ | v
| '------' .--+---. | | | .------.
| | Bundle |<------' | | | Digest |
| .------. '--+---' | v '--+---'
+-----+ DEB-C |<------' ^ .---+----. |
| '------' | | submod |<---'
| | '--------'
v | ^
.--------------. | |
| Nested-Token +-----------------+------------'
'--------------'
.-------. .---------. .------.
Legenda: | Process | | Wire Fmt | | CDDL |
'-------' '---------' '------'
Figure 2: EAT Types
3. A Media Type Parameter for EAT Profiles
EAT is an open and flexible format. To improve interoperability,
Section 7 of [EAT] defines the concept of EAT profiles. Profiles are
used to constrain the parameters that producers and consumers of a
specific EAT profile need to understand in order to interoperate.
For example: the number and type of claims, which serialisation
format, the supported signature schemes, etc. EATs carry an in-band
profile identifier using the eat_profile claim (see Section 4.3.3 of
[EAT]). The value of the eat_profile claim is either an OID or a
URI.
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The media types defined in this document include an optional profile
parameter that can be used to mirror the eat_profile claim of the
transported EAT. Exposing the EAT profile at the API layer allows
API routers to dispatch payloads directly to the profile-specific
processor without having to snoop into the request bodies. This
design also provides a finer-grained and scalable type system that
matches the inherent extensibility of EAT. The expectation being
that a certain EAT profile automatically obtains a media type derived
from the base (e.g., application/eat-cwt) by populating the profile
parameter with the corresponding OID or URL.
4. Examples
The example in Figure 3 illustrates the usage of EAT media types for
transporting attestation evidence.
POST /challenge-response/v1/session/1234567890 HTTP/1.1
Host: verifier.example
Accept: application/eat-cwt; profile=tag:ar4si.example,2021
Content-Type: application/eat-cwt; profile=tag:evidence.example,2022
[ CBOR-encoded EAT w/ profile=tag:evidence.example,2022 ]
Figure 3: Example REST Verification API (request)
The example in Figure 4 illustrates the usage of EAT media types for
transporting attestation results.
HTTP/1.1 200 OK
Content-Type: application/eat-cwt; profile=tag:ar4si.example,2021
[ CBOR-encoded EAT w/ profile=tag:ar4si.example,2021 ]
Figure 4: Example REST Verification API (response)
In both cases the profile is carried as an explicit parameter.
5. Security Considerations
The security consideration of [EAT] and [UCCS] apply in full.
6. IANA Considerations
// RFC Editor: please replace RFCthis with this RFC number and remove
// this note.
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6.1. Media Types
IANA is requested to add the following media types to the "Media
Types" registry [IANA.media-types].
+==============+==========================+======================+
| Name | Template | Reference |
+==============+==========================+======================+
| EAT CWT | application/eat-cwt | RFCthis, Section 6.2 |
+--------------+--------------------------+----------------------+
| EAT JWT | application/eat-jwt | RFCthis, Section 6.3 |
+--------------+--------------------------+----------------------+
| EAT CBOR DEB | application/eat-deb+cbor | RFCthis, Section 6.4 |
+--------------+--------------------------+----------------------+
| EAT JSON DEB | application/eat-deb+json | RFCthis, Section 6.5 |
+--------------+--------------------------+----------------------+
| EAT UCCS | application/eat-ucs+cbor | RFCthis, Section 6.6 |
+--------------+--------------------------+----------------------+
| EAT UJCS | application/eat-ucs+json | RFCthis, Section 6.7 |
+--------------+--------------------------+----------------------+
Table 1: New Media Types
6.2. application/eat-cwt Registration
Type name: application
Subtype name: eat-cwt
Required parameters: n/a
Optional parameters: "profile" (EAT profile in string format. OIDs
MUST use the dotted-decimal notation. The parameter value is
case-insensitive.)
Encoding considerations: binary
Security considerations: Section 5 of RFCthis
Interoperability considerations: n/a
Published specification: Section 6.1 of RFCthis
Applications that use this media type: Attesters, Verifiers,
Endorsers and Reference-Value providers, Relying Parties that need
to transfer EAT payloads over HTTP(S), CoAP(S), and other
transports.
Fragment identifier considerations: n/a
Person & email address to contact for further information: RATS WG
mailing list (rats@ietf.org)
Intended usage: COMMON
Restrictions on usage: none
Author/Change controller: IETF
Provisional registration:
// maybe
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6.3. application/eat-jwt Registration
Type name: application
Subtype name: eat-jwt
Required parameters: n/a
Optional parameters: "profile" (EAT profile in string format. OIDs
MUST use the dotted-decimal notation. The parameter value is
case-insensitive.)
Encoding considerations: 8bit
Security considerations: Section 5 of RFCthis
Interoperability considerations: n/a
Published specification: Section 6.1 of RFCthis
Applications that use this media type Attesters, Verifiers,
Endorsers and Reference-Value providers, Relying Parties that need
to transfer EAT payloads over HTTP(S), CoAP(S), and other
transports.
Fragment identifier considerations: n/a
Person & email address to contact for further information: RATS WG
mailing list (rats@ietf.org)
Intended usage: COMMON
Restrictions on usage: none
Author/Change controller: IETF
Provisional registration:
// maybe
6.4. application/eat-deb+cbor Registration
Type name: application
Subtype name: eat-deb+cbor
Required parameters: n/a
Optional parameters: "profile" (EAT profile in string format. OIDs
MUST use the dotted-decimal notation. The parameter value is
case-insensitive.)
Encoding considerations: binary
Security considerations: Section 5 of RFCthis
Interoperability considerations: n/a
Published specification: Section 6.1 of RFCthis
Applications that use this media type: Attesters, Verifiers,
Endorsers and Reference-Value providers, Relying Parties that need
to transfer EAT payloads over HTTP(S), CoAP(S), and other
transports.
Fragment identifier considerations: n/a
Person & email address to contact for further information: RATS WG
mailing list (rats@ietf.org)
Intended usage: COMMON
Restrictions on usage: none
Author/Change controller: IETF
Provisional registration:
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// maybe
6.5. application/eat-deb+json Registration
Type name: application
Subtype name: eat-deb+json
Required parameters: n/a
Optional parameters: "profile" (EAT profile in string format. OIDs
MUST use the dotted-decimal notation. The parameter value is
case-insensitive.)
Encoding considerations: Same as [RFC7159]
Security considerations: Section 5 of RFCthis
Interoperability considerations: n/a
Published specification: Section 6.1 of RFCthis
Applications that use this media type Attesters, Verifiers,
Endorsers and Reference-Value providers, Relying Parties that need
to transfer EAT payloads over HTTP(S), CoAP(S), and other
transports.
Fragment identifier considerations: n/a
Person & email address to contact for further information: RATS WG
mailing list (rats@ietf.org)
Intended usage: COMMON
Restrictions on usage: none
Author/Change controller: IETF
Provisional registration:
// maybe
6.6. application/eat-ucs+cbor Registration
Type name: application
Subtype name: eat-ucs+cbor
Required parameters: n/a
Optional parameters: "profile" (EAT profile in string format. OIDs
MUST use the dotted-decimal notation. The parameter value is
case-insensitive.)
Encoding considerations: binary
Security considerations: Section 5 of RFCthis
Interoperability considerations: n/a
Published specification: Section 6.1 of RFCthis
Applications that use this media type: Attesters, Verifiers,
Endorsers and Reference-Value providers, Relying Parties that need
to transfer EAT payloads over HTTP(S), CoAP(S), and other
transports.
Fragment identifier considerations: n/a
Person & email address to contact for further information: RATS WG
mailing list (rats@ietf.org)
Intended usage: COMMON
Restrictions on usage: none
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Author/Change controller: IETF
Provisional registration:
// maybe
6.7. application/eat-ucs+json Registration
Type name: application
Subtype name: eat-ucs+json
Required parameters: n/a
Optional parameters: "profile" (EAT profile in string format. OIDs
MUST use the dotted-decimal notation. The parameter value is
case-insensitive.)
Encoding considerations: Same as [RFC7159]
Security considerations: Section 5 of RFCthis
Interoperability considerations: n/a
Published specification: Section 6.1 of RFCthis
Applications that use this media type Attesters, Verifiers,
Endorsers and Reference-Value providers, Relying Parties that need
to transfer EAT payloads over HTTP(S), CoAP(S), and other
transports.
Fragment identifier considerations: n/a
Person & email address to contact for further information: RATS WG
mailing list (rats@ietf.org)
Intended usage: COMMON
Restrictions on usage: none
Author/Change controller: IETF
Provisional registration:
// maybe
6.8. Content-Format
| (*Issue*: need a way to pass the profile information when using
| content formats. A new CoAP option?)
IANA is requested to register a Content-Format number in the "CoAP
Content-Formats" sub-registry, within the "Constrained RESTful
Environments (CoRE) Parameters" Registry [IANA.core-parameters], as
follows:
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+==========================+================+======+===========+
| Content-Type | Content Coding | ID | Reference |
+==========================+================+======+===========+
| application/eat-cwt | - | TBD1 | RFCthis |
+--------------------------+----------------+------+-----------+
| application/eat-jwt | - | TBD2 | RFCthis |
+--------------------------+----------------+------+-----------+
| application/eat-deb+cbor | - | TBD3 | RFCthis |
+--------------------------+----------------+------+-----------+
| application/eat-deb+json | - | TBD4 | RFCthis |
+--------------------------+----------------+------+-----------+
| application/eat-ucs+cbor | - | TBD5 | RFCthis |
+--------------------------+----------------+------+-----------+
| application/eat-ucs+json | - | TBD6 | RFCthis |
+--------------------------+----------------+------+-----------+
Table 2: New Content-Formats
TBD1..6 are to be assigned from the space 256..999.
In the registry as defined by Section 12.3 of [CoAP] at the time of
writing, the column "Content-Type" is called "Media type" and the
column "Content Coding" is called "Encoding".
// RFC editor: please remove this paragraph.
7. References
7.1. Normative References
[CoAP] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/rfc/rfc7252>.
[EAT] Lundblade, L., Mandyam, G., and J. O'Donoghue, "The Entity
Attestation Token (EAT)", Work in Progress, Internet-
Draft, draft-ietf-rats-eat-13, 20 May 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-rats-
eat-13>.
[IANA.core-parameters]
IANA, "Constrained RESTful Environments (CoRE)
Parameters",
<https://www.iana.org/assignments/core-parameters>.
[IANA.media-types]
IANA, "Media Types",
<https://www.iana.org/assignments/media-types>.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <https://www.rfc-editor.org/rfc/rfc7159>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[UCCS] Birkholz, H., O'Donoghue, J., Cam-Winget, N., and C.
Bormann, "A CBOR Tag for Unprotected CWT Claims Sets",
Work in Progress, Internet-Draft, draft-ietf-rats-uccs-02,
12 January 2022, <https://datatracker.ietf.org/doc/html/
draft-ietf-rats-uccs-02>.
7.2. Informative References
[RATS-Arch]
Birkholz, H., Thaler, D., Richardson, M., Smith, N., and
W. Pan, "Remote Attestation Procedures Architecture", Work
in Progress, Internet-Draft, draft-ietf-rats-architecture-
16, 24 May 2022, <https://datatracker.ietf.org/doc/html/
draft-ietf-rats-architecture-16>.
Acknowledgments
TODO
Authors' Addresses
Laurence Lundblade
Security Theory LLC
Email: lgl@securitytheory.com
Henk Birkholz
Fraunhofer Institute for Secure Information Technology
Rheinstrasse 75
64295 Darmstadt
Germany
Email: henk.birkholz@sit.fraunhofer.de
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Thomas Fossati
arm
Email: thomas.fossati@arm.com
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