Relationship Credential (VRC)

A Verifiable Relationship Credential attests to a trust relationship between two entities, from the perspective of the issuer. It’s a primary building block of the Decentralized Trust Graph and an Edge Credential — it forms graph structure between existing entities.

Bidirectionality: Two VRCs = One Edge

The spec is explicit: “Two VRCs (one each direction) form a complete DTG edge.” A relationship is verified through a bi-directional pair of VRCs. When Alice and Bob establish a trust relationship, each issues one VRC to the other. Alice’s VRC says “I trust Bob”; Bob’s VRC says “I trust Alice.” Together, these two credentials form a complete, bilateral trust edge in the graph — the relationship doesn’t exist in the DTG until both halves are issued.

The Relationship Protocol

Establishing a relationship and exchanging VRCs follows a multi-step protocol over DIDComm:

1. Request — Alice sends a relationship request to Bob
2. Accept — Bob accepts the request
3. Finalize — both parties confirm, creating a private channel with a dedicated R-DID (Relationship DID)
4. VRC Request — either party requests a formal credential
5. VRC Issuance — the other party issues a signed VRC

The spec requires that each entity MUST generate a new, unique R-DID for every single entity they connect with, even within the same community. This is critical for privacy — your M-DID isn’t exposed in individual relationships.

For witnessed exchanges, see the Witnessed VRC Exchange Protocol.

What a VRC Contains

• Issuer — the R-DID or M-DID of the person attesting
• Subject — the R-DID or M-DID of the counterparty
• Type — ["VerifiableCredential", "DTGCredential", "RelationshipCredential"]
• Validity period — when the attestation is valid
• Proof — EdDSA JCS 2022 Data Integrity signature

ZKP Presentation

VRCs can stand alone — two individuals can issue VRCs to each other without either being a member of any VTC, and the resulting edge is a valid trust attestation. The cryptographic signatures speak for themselves; the meaning of the attestation is whatever real-world context the parties bring to it.

The spec defines two ZKP constructions for VRCs and recommends ZKP presentation by default whenever privacy matters. See zero-knowledge-proofs for the full discussion.

Pairwise ZKP (per VRC, no shared community required)

The holder of a VRC MAY construct a zero-knowledge proof that demonstrates possession of a valid VRC and selectively discloses chosen attributes, subject DIDs, or predicates over them. The canonical application is to disclose the parties’ P-DIDs while hiding the underlying R-DIDs — a public, verifiable claim that two known personas have a relationship, without exposing the private pairwise channel between them or enabling correlation across the holder’s other presentations.

This construction is available to any two parties who hold a VRC between them, regardless of shared community membership. It does not by itself confer community-level assurance like personhood; whatever assurance it carries derives from out-of-band context, the public reputation of any disclosed persona DIDs, and the cryptographic integrity of the VRC.

Community-Anchored ZKP (when both parties hold VMCs from the same community)

When both parties to a VRC hold VMCs from the same community, the holder MAY additionally construct a community-anchored ZKP of the relationship — anchored under VMC §5.2. The proof demonstrates:

1. Possession of the VRC
2. Possession of the underlying VMC (proving membership)
3. The VRC issuer holds a VMC from the same C-DID

This proof anchors the relationship within a community’s governance context — when the community’s VMCs are also PHCs, that personhood assurance carries forward — without revealing the underlying DIDs. It is one proof construction available to relationships within a shared community, not a universal precondition for issuing or holding a VRC.

Trust Graph Significance

VRCs are the edges that make the trust graph traversable. When evaluating trust in someone you don’t know directly, you look for paths through the graph — chains of VRCs connecting you to them through mutual connections. Multiple independent paths increase confidence.

VRCs can be strengthened by Witness Credentials and complemented by Endorsement Credentials, Persona Credentials, and other Annotation Credentials.

See also: zero-knowledge-proofs, dtg-credentials-overview, credential-categories, witnessed-vrc-exchange, did-types