Basic Session Credential Grant Type for the Agent Enrollment Protocol

Introduction AEP session credentials allow a Service to issue a stateful credential after an Agent authenticates with a baseline AEP client assertion . This document defines the basic grant type for Services that want to reuse HTTP Basic authentication while preserving AEP key possession as the issuance root. Grant type request and response bodies are JSON objects carried over HTTP semantics as defined by AEP. This grant type does not replace baseline AEP authentication. Services that implement this grant type MUST continue to accept baseline AEP authentication on authenticated AEP commands.

Requirements Language 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.

Grant Type The grant type identifier is:

A Service that enables this grant type lists basic in commands.grant_types and lists grant and revoke in commands.supported in its AEP Inspect document.

Inspect Configuration A Service MAY publish configuration under commands.grant_types_config.basic:

default_lifetime_seconds is an AEP-owned numeric value and is therefore represented as a JSON string. realm, when present, identifies the HTTP Basic realm associated with credentials issued by this grant type. scopes_supported, when present, lists Service-defined scope strings an Agent can request. supports_per_credential_revoke is a string boolean. If absent, the default is "false". Every successful Grant response includes credential_id. When this value is "true", the Service MUST support a Revoke request containing both grant_type and that credential_id. When this value is "false" or absent, the Agent MUST use grant-type or all-grant-types Revoke instead.

Grant Request The Agent invokes AEP Grant using baseline Authorization: AEP <jwt> authentication with op equal to grant.

grant_type MUST be basic. label is OPTIONAL and is an Agent-provided display label. Services MAY ignore it. requested_scopes is OPTIONAL. A Service MAY grant fewer scopes than requested. Unsupported requested scopes MAY be omitted from the response scopes array. If the Service cannot issue a useful credential for the requested scopes, it MUST return invalid_request. The Agent does not submit a password. The Service generates the username and password, or generates the password for a Service-owned username, and returns the credential in the Grant response.

Grant Response A successful Grant response is a JSON object:

username and password are REQUIRED. Agents MUST treat password as an opaque secret. Services MUST generate values that can be encoded according to RFC 7617 without lossy transformation. Generated passwords MUST contain at least 128 bits of entropy. Generated usernames and passwords MUST NOT contain control characters. expires_at is REQUIRED and is an RFC 3339 timestamp for credential expiry. realm, when present, identifies the associated HTTP Basic realm. scopes is OPTIONAL and contains the granted scope strings when present. A missing or null value means the Basic credential has no scope-limited authorization. The Service MAY return an empty array with the same meaning. credential_id is REQUIRED and is a stable Service-issued identifier for the issued Basic credential. It follows the Service-wide uniqueness and non-reassignment requirements in the Core Grant command. It is not the username or password and is not used for credential presentation. The Agent stores it with the credential and sends it only when targeting that credential in a Revoke request supported by the Service. The response does not include the base64-encoded Authorization value. Agents construct that value locally from username ":" password according to RFC 7617.

Credential Presentation On later HTTP requests, the Agent presents the credential using HTTP Basic authentication:

On protected resources, the Agent MAY instead use the dedicated AEP carrier while preserving the Basic field value:

Services implementing this grant type MUST accept both carriers on protected resources. Agents MUST use only one AEP carrier per request, and the ambiguity and precedence rules are defined by AEP core. The encoded value is standard base64 of username ":" password as defined by RFC 7617. This encoding is not AEP's base64url binary convention. Authenticated AEP command endpoints MUST continue to accept baseline AEP authentication.

Revoke The Agent invokes AEP Revoke using baseline Authorization: AEP <jwt> authentication with op equal to revoke. To revoke all Basic credentials of this type for the authenticated Agent:

When the Service advertises per-credential Revoke, the Agent can revoke one Basic credential:

Revoke returns an empty JSON object on success. The Service MUST return success regardless of whether a matching credential existed. To revoke all session credentials of every grant type, Agents use the core all_grant_types Revoke request.

Error Handling This grant type uses the AEP error vocabulary defined by the core protocol. A Basic credential that is expired, malformed, revoked, unknown, or bound to a different Agent fails as not_recognized.

IANA Considerations This document requests registration of basic in the AEP Grant Types registry. Field Value Grant Type basic Description HTTP Basic credential issued through AEP Grant Reference This document

Security Considerations Basic credentials are bearer secrets once encoded into the Authorization header. Services MUST store passwords using strong password-storage controls. Services MUST NOT log raw passwords or Authorization header values, and Services MUST support AEP Revoke for every advertised grant type. Agents that suspect credential disclosure SHOULD call AEP Revoke using baseline AEP authentication and then fall back to per-request signed client assertions until a new credential is issued. Services SHOULD use a distinct realm or credential store for AEP-issued Basic credentials when the Service also supports human-facing Basic credentials.

Privacy Considerations Basic credentials can become correlation handles if reused outside the issuing Service. Agents MUST NOT present AEP-issued Basic credentials to other Services. Services MUST NOT log raw passwords or Authorization header values in ordinary logs or telemetry.