| Internet-Draft | CAT-4-MOQT | March 2026 |
| Law, et al. | Expires 4 September 2026 | [Page] |
A token-based authentication scheme for use with Media Over QUIC Transport.¶
This note is to be removed before publishing as an RFC.¶
The latest revision of this draft can be found at https://moq-wg.github.io/CAT-4-MOQT/. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-ietf-moq-c4m/.¶
Discussion of this document takes place on the Media Over QUIC mailing list (mailto:moq@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/moq/. Subscribe at https://www.ietf.org/mailman/listinfo/moq/.¶
Source for this draft and an issue tracker can be found at https://github.com/moq-wg/CAT-4-MOQT.¶
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 4 September 2026.¶
Copyright (c) 2026 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 extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
This draft introduces a token-based authentication scheme for use with MOQT [MoQTransport]. The scheme protects access to the relay during session establishment and also contrains the actions which the client may take once connected.¶
This draft defines version 1 of this specification.¶
An end-user logs-in to a distribution service. The service authenticates the user (via username/password, OAuth, 2FA or another method). The methods involved in this authentication step lie outside the scope of this draft.¶
Based upon the identity and permissions granted to that end-user, the service generates a token. A token is a data structure that has been serialized into a byte array. The token encodes information such as the user's ID, constraints on how and when they can access the MOQT distribution network and contraints on the actions they can take once connected. The token may be signed to make it tamper-resistent.¶
The token is given in the clear to the end-user, along with a URL to connect to the edge relay of a MOQT distribution network. The edge relay is part of a trusted MOQT distribution network. It has previously shared secrets with the distribution service, so that this relay is entitled to decrypt related tokens and to validate signatures.¶
The end-user client application provides the token to the MOQT distribution relay when it connects. This connection may be established over WebTransport or raw QUIC.¶
The relay decrypts the token upon receipt and validates the signature. Based upon claims conveyed in the token, the relay accepts or rejects the connection.¶
If the relay accepts the connection, then the client will take a series of MOQT actions: PUBLISH_NAMESPACE, SUBSCRIBE_NAMESPACE, SUBSCRIBE or FETCH. For each of these, it will supply the token it received using the AUTHENTICATION parameter.¶
As an alternative to this workflow, the distribution service may vend multiple tokens to the client. The client may use one of those tokens to establish the initial conneciton and others to authenticate its actions.¶
End User Distribution Service MOQT Relay
| | |
| | 0. Share secrets |
| |<----------------------->|
| | (offline/pre-setup) |
| | |
| 1. Login/Authenticate | |
|<----------------------->| |
| | |
| 2. Generate C4M Token | |
| + Relay URL | |
|<------------------------| |
| | |
| 3. Connect to Relay with Token |
|-------------------------------------------------->|
| | |
| | 4. Validate Token |
| |<----------------------->|
| | (previously shared |
| | secrets) |
| | |
| 5. Accept/Reject Connection |
|<--------------------------------------------------|
| | |
| 6. MOQT Actions with Token Authentication |
|<------------------------------------------------->|
| (PUBLISH_NAMESPACE, SUBSCRIBE, PUBLISH, FETCH)|
| | |
| | 7. Revalidate Token |
| |<----------------------->|
| | (if moqt-reval set, |
| | repeats at interval |
| | e.g., every 5 min) |
¶
This draft uses a single token format, namely the Common Access Token (CAT) [CAT]. The token is supplied as a byte array. When it must be cast to a string for inclusion in a URL, it is Base64 encoded [BASE64].¶
To provide control over the MOQT actions, this draft defines a new CBOR Web Token (CWT) Claim called "moqt". Use of the moqt claim is optional for clients. Support for processing the moqt claim is mandatory for relays.¶
The default for all actions is "Blocked" and this does not need to be communicated in the token. As soon as a token is provided, all actions are explicitly blocked unless explicitly enabled.¶
The "moqt" claim is defined by the following CDDL:¶
$$Claims-Set-Claims //= (moqt-label => moqt-value) moqt-label = TBD_MOQT moqt-value = [ + moqt-scope ] moqt-scope = [ moqt-actions, ? [ + moqt-ns-match ], ? moqt-track-match ] moqt-actions = [ + moqt-action ] moqt-action = int moqt-ns-match = bin-match / nil moqt-track-match = bin-match bin-match = bstr / [ match-type, match-value ] match-type = prefix-match / suffix-match match-value = bstr prefix-match = 1 suffix-match = 2¶
The "moqt" claim bounds the scope of MOQT actions for which the token can provide access. It is an array of action scopes. Each scope is an array with three elements: an array of integers that identifies the actions, an array of match objects for the namespace, and a match object for the track name.¶
The actions are integers defined as follows:¶
| Action | Key | Reference |
|---|---|---|
| CLIENT_SETUP | 0 | [MoQTransport] Section 9.3 |
| SERVER_SETUP | 1 | [MoQTransport] Section 9.3 |
| PUBLISH_NAMESPACE | 2 | [MoQTransport] Section 9.20 |
| SUBSCRIBE_NAMESPACE | 3 | [MoQTransport] Section 9.25 |
| SUBSCRIBE | 4 | [MoQTransport] Section 9.9 |
| REQUEST_UPDATE | 5 | [MoQTransport] Section 9.11 |
| PUBLISH | 6 | [MoQTransport] Section 9.13 |
| FETCH | 7 | [MoQTransport] Section 9.16 |
| TRACK_STATUS | 8 | [MoQTransport] Section 9.19 |
The scope of the moqt claim is limited to the actions provided in the array. Any action not present in the array is not authorized by moqt claim.¶
When a match object is a byte string, it is an exact match. When a match object is an array, the first element is the match type and the second is the match value. Matches are performed bytewise against the corresponding field of the Full Track Name (as defined in Section 2.4.1 of [MoQTransport]). The first namespace match object is applied to the first field in the Track Namespace, and so on. The match for the track name is matched against the Track Name. Exact matches must match exactly, prefix matches must match the beginning of the byte string, and suffix matches must match the end of the byte string.¶
The track namespace match and track name match are optional. If the length of the scope array is two, then no track name match is performed at all and the scope of the token includes all track names. If the length is one, the scope includes all namespaces as well as no matching is performed. The list of actions is mandatory.¶
A nil match object is special: it only matches the end of the list of namespaces. This allows the scope to be limited to a precise namespace. If the list of namespace match objects does not end with a nil match object, then the scope includes all longer namespaces that start with fields that match.¶
No normalization is applied to the values against which to match; it is performed bytewise.¶
Full Track Names in this draft are represented using Extended Diagnostic Notation (EDN) as defined in [EDN] as an array with two elements: an array of namespace fields and a track name.¶
Example: Allow with an exact match [['example','com'],'/bob']¶
{
/moqt/ TBD_MOQT: [[
[ /ANNOUNCE/ 2, /SUBSCRIBE_NAMESPACE/ 3, /PUBLISH/ 6, /FETCH/ 7 ],
['example','com',nil],
'/bob'
]]
}
¶
Permits * [['example','com'], '/bob'] Prohibits * [['example','com'], ''] * [['example','com'], '/bob/123'] * [['example','com'], '/alice'] * [['example','com'], '/bob/logs'] * [['alternate','example','com'], '/bob'] * [['12345'], ''] * [['example'], 'com/bob'] * [['example','com','/bob'], ''] * [['example','com',''], '/bob']¶
Example: Allow with a prefix match [['example','com'],'/bob']¶
{
/moqt/ TBD_MOQT: [[
[ /ANNOUNCE/ 2, /SUBSCRIBE_NAMESPACE/ 3, /PUBLISH/ 6, /FETCH/ 7 ],
['example','com',nil],
[ /prefix/ 1, '/bob']
]]
}
¶
Permits * [['example','com'], '/bob'] * [['example','com'], '/bob/123'] * [['example','com'], '/bob/logs'] Prohibits * [['example','com'], ''] * [['example','com'], '/alice'] * [['alternate','example','com'], '/bob'] * [['12345'], ''] * [['example'], 'com/bob']¶
Example: Allow with a prefix match on namespace and exact match on track name [['example','com'],'/bob']
~~~~~~~~~~~~~~~
{
/moqt/ TBD_MOQT: [[
[ /PUBLISH_NAMESPACE/ 2, /SUBSCRIBE_NAMESPACE/ 3, /PUBLISH/ 6, /FETCH/ 7 ],
{ /exact/ 0: 'example.com'},
{ /exact/ 0: '/bob'}
]]
}
~~~~~~~~~~~~~~~¶
Permits * [['example','com'], '/bob'] * [['example','com',''], '/bob'] * [['example','com','bob'], '/bob'] Prohibits * [['example','com'], ''] * [['example','com'], '/bob/123'] * [['example','com'], '/alice'] * [['example','com'], '/bob/logs'] * [['alternate','example','com'], '/bob'] * [['12345'], ''] * [['example'], 'com/bob'] * [['example','com','/bob'], '']¶
Example: Allow with a prefix match on namespace [['example','com']].
~~~~~~~~~~~~~~~
{
/moqt/ TBD_MOQT: [[
[ /PUBLISH_NAMESPACE/ 2, /SUBSCRIBE_NAMESPACE/ 3, /PUBLISH/ 6, /FETCH/ 7 ],
['example','com']
]]
}
~~~~~~~~~~~~~~~¶
Permits * [['example','com'], '/bob'] * [['example','com',''], '/bob'] * [['example','com','bob'], '/bob'] * [['example','com'], ''] * [['example','com'], '/bob/123'] * [['example','com'], '/alice'] * [['example','com'], '/bob/logs'] * [['example','com','/bob'], ''] Prohibits * [['alternate','example','com'], '/bob'] * [['12345'], ''] * [['example'], 'com/bob']¶
Multiple actions may be communicated within the same token, with different permissions. This can be facilitated by the logical claims defined in [Composite] or simply by defining multiple limits, depending on the required restrictions. In both cases, the order in which limits are declared and evaluated is unimportant. The evaluation stops after the first acceptable result is discovered.¶
{
/moqt/ TBD_MOQT: [
[[/PUBLISH/ 6], ['example','com',nil], [ /prefix/ 1, 'bob']],
[[/PUBLISH/ 6], ['example','com',nil], 'logs/12345/bob']
],
/exp/ 4: 1750000000
}
¶
(1) PUBLISH (Allow with a prefix match) [['example','com'],'/bob']¶
(2) PUBLISH (Allow with an exact match) [['example','com'],'/logs/12345/bob']¶
Evaluating [['example','com'],'/bob/123'] would succeed on test 1 and test 2 would never be evaluated.
Evaluating [['example','com'],'/logs/12345/bob'] would fail on test 1 but then succeed on test 2.
Evaluating [['example','com'],''] would fail on test 1 and on test 2.¶
In addition, the entire token expires at 2025-05-02T21:57:24+00:00.¶
The "moqt-reval" claim is defined by the following CDDL:¶
$$Claims-Set-Claims //= (moqt-reval-label => moqt-reval-value) moqt-reval-label = TBD_MOQT_REVAL moqt-reval-value = number¶
The "moqt-reval" claim indicates that the token must be revalidated for ongoing streams. If the token is no longer acceptable, the actions authorized by it MUST not be permitted to continue.¶
The "moqt-reval-value" is a revalidation interval, expressed in seconds. It provides an upper bound on how long a token may be considered acceptable for an ongoing stream. A revalidator MAY revalidate sooner.¶
If the revalidation interval is smaller than the recipient is prepared or able to revalidate, the recipient MUST reject the token. If a recipient is unable to revalidate tokens, it MUST reject all tokens with a "moqt-reval" claim.¶
A token can be revalidated by simply validating it again, just as if it were new. However, since some claims, signatures, MACs, and other attributes that could contribute to unacceptability may be incapable of changing acceptability in the duration, a revalidator may optimize by skipping some of the checks as long as the outcome of the validation is the same. Revalidators SHOULD skip reverifying MACs and signatures when the list of acceptable issuer keys is unchanged.¶
When the value of this claim is zero, the token MUST NOT be revalidated. This is the default behaviour when the claim is not present.¶
This claim MUST NOT be used outside of a base claimset. If used within a composition claims, the token is not well-formed.¶
The claim key for this claim is TBD_MOQT_REVAL and the claim value is a number. Recipients MUST support this claim. This claim is OPTIONAL for issuers.¶
This section defines the use of CAT's Demonstrating Proof of Possession (DPoP) claims [DPoP] to enhance security in MOQT environments. This approach leverages the CAT token's "cnf" (confirmation) claim with JWK Thumbprint binding and the "catdpop" (CAT DPoP Settings) claim to provide proof-of-possession capabilities that prevent token theft and replay attacks in MOQT systems.¶
This proposal extends the CAT authentication model by binding tokens to client cryptographic key pairs. To enable sender-constrained token usage, the CAT tokens include DPoP-related claims as defined [CAT] Section 4.8, ensuring that only the legitimate token holder can use the token for MOQT operations.¶
DPoP binding is accomplished by providing the "cnf" claim with the "jkt" (JWK Thumbprint) confirmation method.¶
Below is an example showing jkt token binding.¶
{
/ cnf / 8: {
/ jkt / 3: h'0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef' / 32-byte SHA-256 JWK thumbprint (hex-encoded) /
},
/ moqt / TBD_MOQT: [
[
[/PUBLISH_NAMESPACE/ 2, /SUBSCRIBE_NAMESPACE/ 3, /PUBLISH/ 6, /FETCH/ 7],
['cdn','example','com',nil],
[ /prefix/ 1, '/sports/']
]
],
/ catdpop /
321: {
0: 300, / 5-minute window /
1: 1 / Honor jti for replay protection /
},
/ exp /
4: 1750000000
}
¶
Implementation Requirements:¶
Relay Validation: MOQT relays MUST verify that DPoP proofs are signed with the private key corresponding to the "jkt" value¶
Proof Binding: Relays MUST reject requests where DPoP proof validation or key binding fails¶
Processing Semantics: Relays MUST process DPoP proofs as Protected Resource Access requests per [DPoP] Section 7¶
This section defines the use of DPoP with an application-agnostic proof framework as specified in [DPOP-PROOF], which extends the traditional HTTP-centric DPoP model to support arbitrary protocols including MOQT. This approach replaces HTTP-specific claims with a flexible authorization context structure that can accommodate protocol-specific command representations.¶
The DPoP proof JWT follows the structure defined in Section 4 of [DPOP-PROOF] with the following required claims:¶
JWT Header:¶
"typ": "dpop-proof+jwt"¶
"alg": Asymmetric signature algorithm identifier¶
"jwk": Public key for verification¶
JWT Payload:¶
For MOQT operations, the Authorization Context ("actx") object contains:¶
"type": "moqt" (registered identifier for MOQT protocol)¶
"action": MOQT action identifier¶
"tns": Track namespace (required)¶
"tn": Track name (required)¶
"resource": MOQT resource identifier (optional)¶
When the optional "resource" parameter is included, it MUST be consistent with the
"tns" and "tn" parameters. The resource URI should follow the format
moqt://<relay-endpoint>?tns=<namespace>&tn=<track> where the tns and tn query
parameters match the respective "tns" and "tn" fields in the Authorization Context.¶
Example DPoP proof for MOQT PUBLISH_NAMESPACE operation:¶
{
"typ": "dpop-proof+jwt",
"alg": "ES256",
"jwk": { ... }
}
.
{
"jti": "unique-request-id",
"iat": 1705123456,
"actx": {
"type": "moqt",
"action": "PUB_NS",
"tns": "sports",
"tn": "live-feed"
}
}
¶
MOQT action mapping for Authorization Context:¶
| MOQT Action | actx.action |
|---|---|
| CLIENT_SETUP | SETUP |
| SERVER_SETUP | SETUP |
| PUBLISH_NAMESPACE | PUB_NS |
| SUBSCRIBE_NAMESPACE | SUB_NS |
| SUBSCRIBE | SUBSCRIBE |
| REQUEST_UPDATE | REQ_UPDATE |
| PUBLISH | PUBLISH |
| FETCH | FETCH |
| TRACK_STATUS | TRK_STATUS |
Relays supporting this application-agnostic DPoP framework MUST:¶
Validate DPoP proofs according to [DPOP-PROOF]¶
Verify that the "actx.type" is "moqt" for MOQT operations¶
Validate that the "actx.action" matches the requested MOQT action¶
Verify that the "actx.tns" corresponds to the target track namespace¶
Verify that the "actx.tn" corresponds to the target track name¶
If present, verify the "actx.resource" is consistent with "tns" and "tn"¶
Reject requests where Authorization Context validation fails¶
The Authorization Context "resource" field should specify track namespace (tns) and track name (tn) parameters for MOQT resources:¶
The following process illustrates how DPoP proof provision results in CAT token binding and subsequent MOQT relay validation:¶
┌──────────────┐ ┌─────────────────────┐ ┌──────┐
│MOQT Client │ │Authorization Server │ │MOQT │
│ │ │ │ │Relay │
└──────┬───────┘ └──────────┬──────────┘ └──────┘
│ │ │
│ (1) Generate Key Pair │ │
│ EC P-256/RSA │ │
│ private_key, public_key │ │
│ │ │
│ (2) Authentication Request │ │
│ + User Credentials │ │
│ + Public Key (JWK format) │ │
├──────────────────────────────────►│ │
│ │ │
│ │ (3) User Authentication │
│ │ & Authorization │
│ │ │
│ │ (4) Generate CAT Token: │
│ │ • "cnf" claim with │
│ │ "jkt": SHA256(public_key)│
│ │ • "catdpop" processing │
│ │ settings │
│ │ • "moqt" action scope │
│ │ • Sign with shared secret │
│ │ │
│ (5) CAT Token Response │ │
│ + Bound CAT Token │ │
│ + Relay Endpoint URL │ │
|◄──────────────────────────────────┤ │
│ │ │
¶
Steps 1-5 Detail:¶
Client Key Generation: The MOQT client generates an asymmetric key pair (typically EC P-256) for DPoP operations¶
Authentication with Public Key: Client authenticates with the authorization server, providing user credentials and the public key¶
User Authentication: Authorization server validates user identity and permissions¶
CAT Token Generation: Server creates a CAT token containing:¶
Token Delivery: Server provides the bound CAT token and relay endpoint information to the client¶
┌──────────────┐ ┌─────────────────────┐ ┌───────┐
│MOQT Client │ │Authorization Server │ │MOQT │
│ │ │ │ │Relay │
└──────┬───────┘ └──────────┬──────────┘ └──────┬┘
│ │ │
│ │ │
│ (6) For each MOQT action: │ │
│ Create fresh DPoP proof JWT │ │
│ • Header: typ="dpop-proof+jwt"│ │
│ • alg, jwk │ │
│ • Claims: jti, iat, actx │ │
│ • Sign with private_key │ │
│ │ │
│ (7) MOQT Request │ │
│ + CAT Token │ │
│ + Fresh DPoP Proof │ │
│ (CLIENT_SETUP, PUBLISH_NAMESPACE,│ │
│ SUBSCRIBE, PUBLISH, FETCH) │ │
├─────────────────────────────────────────────────────────────────────►│
│ │ │
│ │ (8)│
│ │ CAT Validation: │
│ │ • Verify token │
│ │ signature │
│ │ • Validate claims│
│ │ including exp, |
| | scope │
│ │ │
│ │ (9)│
│ │ DPoP Validation: │
│ │ • Extract "jkt" │
│ │ from token │
│ │ • Verify DPoP │
│ │ JWT signature │
│ │ • Validate key │
│ │ binding │
│ │ • Check │
│ │ freshness │
│ │ │
│ │ (10)│
│ │ Action Authorization│
│ │ • Match action │
│ │ to token scope│
│ │ • Check ns/track│
│ │ permissions │
│ │ │
│ (11) Response │ │
│ Success/Error │ │
◄─────────────────────────────────────────────────────────────────────┤
│ │ │
¶
Steps 6-11 Detail:¶
DPoP Proof Creation: For each MOQT action, the client creates a fresh DPoP proof JWT with:¶
MOQT Request: Client sends MOQT action with both CAT token and fresh DPoP proof¶
CAT Token Validation: Relay validates:¶
DPoP Proof Validation: Relay performs:¶
Extract "jkt" (JWK Thumbprint) from CAT token's "cnf" claim¶
Verify DPoP JWT signature using embedded public key¶
Confirm that SHA-256 hash of DPoP public key matches "jkt" value¶
Check proof freshness within "catdpop" window settings¶
Process replay protection based on "jti" settings¶
Validate Authorization Context ("actx") according to [DPOP-PROOF]¶
Verify "actx.type" is "moqt"¶
Validate "actx.action" matches the requested MOQT action¶
Verify "actx.tns" and "actx.tn" correspond to target resources¶
Action Authorization: Relay validates the specific MOQT action against token scope and namespace/track permissions¶
Response: Relay responds with success or appropriate error information¶
Any time an application wishes to add a CAT token to a URL or path element, the token SHOULD first be Base64 encoded [BASE64]. The syntax and method of modifying the URL is left to the application to define and is not constrained by this specification.¶
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.¶
TODO Add security considerations for DPoP Claims¶
IANA will register the following claims in the "CBOR Web Token (CWT) Claims" registry:¶
| moqt | moqt-reval | |
|---|---|---|
| Claim Name | moqt | moqt-reval |
| Claim Description | MOQT Action | MOQT revalidation |
| JWT Claim Name | N/A | N/A |
| Claim Key | TBD_MOQT (1+2) | TBD_MOQT (1+2) |
| Claim Value Type | array | number |
| Change Controller | IESG | IESG |
| Specification Document | RFCthis | RFCthis |
[RFC Editor: Please replace RFCthis with the published RFC number for this document.]¶
The IETF moq workgroup¶