Verification Flow | IDA — Identity for the AI Age

Verification is the process by which a Verifier cryptographically validates a Verifiable Credential or Verifiable Presentation.

Verification Flow Overview

Proof Request

A verifier initiates verification by sending a proof request to the holder:

{
  "type": "https://didcomm.org/present-proof/3.0/request-presentation",
  "id": "proof-req-001",
  "from": "did:adi:verifier001...",
  "to": ["did:adi:holder001..."],
  "body": {
    "goal_code": "verify.degree",
    "will_confirm": true,
    "presentation_definition": {
      "id": "degree-verification",
      "input_descriptors": [
        {
          "id": "degree-credential",
          "name": "University Degree",
          "purpose": "Verify the applicant holds a bachelor's degree",
          "constraints": {
            "fields": [
              {
                "path": ["$.credentialSubject.degree.type"],
                "filter": { "type": "string", "const": "BachelorDegree" }
              },
              {
                "path": ["$.credentialSubject.degree.university"],
                "filter": { "type": "string" }
              }
            ]
          }
        }
      ]
    }
  }
}

This follows the DIF Presentation Exchange v2 format.

Verify a Credential

Request

POST /api/v1/credentials/verify
Content-Type: application/json
{
  "credential": {
    "@context": ["https://www.w3.org/2018/credentials/v1", "..."],
    "type": ["VerifiableCredential", "UniversityDegreeCredential"],
    "issuer": "did:adi:issuer001...",
    "issuanceDate": "2026-03-28T10:00:00Z",
    "credentialSubject": { "..." },
    "credentialStatus": { "..." },
    "proof": { "..." }
  }
}

Response

{
  "verified": true,
  "checks": {
    "proof": {
      "status": "valid",
      "type": "Ed25519Signature2020",
      "verificationMethod": "did:adi:issuer001...#key-1"
    },
    "issuer": {
      "status": "valid",
      "did": "did:adi:issuer001...",
      "active": true
    },
    "schema": {
      "status": "valid",
      "schemaId": "did:adi:schema:university-degree-v1"
    },
    "expiration": {
      "status": "valid",
      "expirationDate": "2030-12-31T23:59:59Z"
    },
    "revocation": {
      "status": "valid",
      "revoked": false,
      "checkedAt": "2026-03-28T12:00:00Z"
    }
  },
  "warnings": []
}

Verify a Presentation

Request

POST /api/v1/presentations/verify
Content-Type: application/json
{
  "presentation": {
    "@context": ["https://www.w3.org/2018/credentials/v1"],
    "type": ["VerifiablePresentation"],
    "holder": "did:adi:holder001...",
    "verifiableCredential": [ { "..." } ],
    "proof": {
      "type": "Ed25519Signature2020",
      "challenge": "abc123-verifier-nonce",
      "domain": "https://verifier.example.com",
      "proofValue": "z4Abc123..."
    }
  },
  "challenge": "abc123-verifier-nonce",
  "domain": "https://verifier.example.com"
}

Response

{
  "verified": true,
  "presentationChecks": {
    "holderProof": "valid",
    "challenge": "matched",
    "domain": "matched"
  },
  "credentialResults": [
    {
      "index": 0,
      "type": "UniversityDegreeCredential",
      "verified": true,
      "checks": {
        "proof": "valid",
        "issuer": "valid",
        "schema": "valid",
        "expiration": "valid",
        "revocation": "valid"
      }
    }
  ]
}

Verification Checks Explained

1. Proof Integrity

The cryptographic signature is verified:

Resolve the verificationMethod from the issuer’s DID Document
Extract the public key
Verify the signature over the canonicalized credential data

2. Issuer DID Resolution

Resolve the issuer DID from the ADI blockchain
Confirm the DID is not deactivated
Confirm the verification method exists in the DID Document
Confirm the key is listed in the assertionMethod relationship

3. Schema Compliance

Fetch the schema from the Schema Registry
Validate credentialSubject attributes against the schema

4. Expiration

Compare expirationDate against current time
If expired, the credential is invalid

5. Revocation

Query the Revocation Registry using credentialStatus
Check the specific statusListIndex in the StatusList2021 bitstring
If the bit is set, the credential has been revoked

Selective Disclosure Verification

For BBS+ credentials, the verifier receives a derived proof:

POST /api/v1/presentations/verify
Content-Type: application/json
{
  "presentation": {
    "verifiableCredential": [
      {
        "credentialSubject": {
          "id": "did:adi:holder001...",
          "degree": {
            "type": "BachelorDegree",
            "university": "MIT"
          }
        },
        "proof": {
          "type": "BbsBlsSignatureProof2020",
          "nonce": "verifier-nonce",
          "proofValue": "DerivedProof123..."
        }
      }
    ]
  }
}

The verifier only sees the disclosed attributes (type and university), but can verify they were part of a validly signed credential.

Verification Failures

Failure	Description	Mitigation
`INVALID_SIGNATURE`	Proof signature does not verify	Credential may be tampered
`ISSUER_DEACTIVATED`	Issuer DID is deactivated	Contact issuer for re-issuance
`CREDENTIAL_EXPIRED`	Current time > expirationDate	Request updated credential
`CREDENTIAL_REVOKED`	Credential is in revocation list	Credential is no longer valid
`SCHEMA_MISMATCH`	Claims do not match schema	Possible schema version mismatch
`CHALLENGE_MISMATCH`	VP challenge does not match	Possible replay attack
`KEY_NOT_FOUND`	Verification method not in DID Doc	Key may have been rotated