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1. Definition 2. Functional Requirements 3. Syntax 4. Semantics

1 Definition

A Trust Message is a signed, structured communication exchanged between entities participating in the MPAI‑PTF Trust Framework. A Trust Message may represent either:

  • a Trust Request, in which an entity asks another entity to perform a trust‑related operation, or
  • a Trust Response, in which an entity returns the result of such a request.

Trust Messages provide a uniform, cryptographically protected mechanism for initiating and responding to trust operations, enabling interoperability, auditability, and policy‑driven verification.

2 Functional Requirements

A Trust Message shall:

  • Identify the message
    • Include a versioned header.
    • Include a unique message identifier.
    • Include the time at which the message was created.
  • Indicate the message type
    • "TrustRequest" or "TrustResponse".
  • Identify the communicating parties
    • A Trust Request shall include a RequesterID.
    • A Trust Response shall include a ResponderID.
  • Carry request information (for TrustRequest)
    • Requested operation.
    • Target object type.
    • Target object identifier.
  • Carry response information (for TrustResponse)
    • Status (Success or Failure).
    • Optional failure reason.
    • Optional result payload.
  • Provide integrity protection
    • Include a digital signature using an algorithm from the Security Algorithm Taxonomy.
  • Support metadata
    • Optional descriptive metadata.
    • Optional Data Exchange Metadata.
  • Reject undeclared fields
    • Only the fields defined in the schema shall be permitted.

3 Syntax

https://schemas.mpai.community/PTF/V1.0/data/TrustMessage.json

4 Semantics

Field Description
Header Version header of the form PTF-MSG-Vx.y.
MessageType Indicates whether the message is a TrustRequest or a TrustResponse.
MessageID Unique identifier of the trust message.
MessageTime Time at which the message was created, using the OSD Time data type.
RequesterID Identifier of the entity making the request (present only for TrustRequest).
ResponderID Identifier of the entity responding (present only for TrustResponse).
Request.Operation The trust operation being requested.
Request.TargetType Type of object the request concerns (e.g., CII, InstanceCredential).
Request.TargetID Identifier of the target object.
Response.Status Result of the request: Success or Failure.
Response.Reason Optional human‑readable reason for failure.
Response.Result Optional result payload returned by the responder.
Signature Digital signature over the entire Trust Message.
Signature.Algorithm Signature algorithm identifier from the Security Algorithm Taxonomy.
Signature.Value Base64url‑encoded digital signature value.
DataXMData Optional Data Exchange Metadata.
DescrMetadata Optional human‑readable descriptive metadata (max 2048 characters).

 

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