---
title: Verifiable Credentials
titleTemplate: Guides
description: Public guide to issuing, verifying and revoking KryptoOS verifiable credentials.
---
KryptoOS uses verifiable credentials to let an issuer make a claim, a holder store it, and a verifier check it without relying on a central database.

## Lifecycle

1. **Issue:** an approved issuer signs a credential for a holder DID.
2. **Hold:** the holder stores the credential in their wallet or app.
3. **Present:** the holder shares the minimum proof needed.
4. **Verify:** the verifier checks issuer, signature, expiry and status.
5. **Revoke:** the issuer can update status without exposing private data.

## Public Credential Shape

```json
{
  "type": ["VerifiableCredential", "ExampleCredential"],
  "issuer": "did:kryptoos:issuer",
  "credentialSubject": {
    "id": "did:kryptoos:holder",
    "claim": "public-or-minimized-value"
  },
  "credentialStatus": {
    "type": "RevocationStatus",
    "status": "active"
  },
  "proof": {
    "type": "Sr25519Signature2026",
    "proofPurpose": "assertionMethod"
  }
}
```

This example is intentionally minimal. Public docs should not include real user identifiers, raw device IDs, private issuer keys or production status-list URLs.

## Verification Checklist

- DID format is valid.
- Issuer is allowed for the credential type.
- Signature verifies against the issuer DID document.
- Credential is not expired.
- Revocation status is active.
- The verifier requested only the claims it needs.

## Ecosystem Credentials

For Ouranoos, Eoonia and EmpoorioChain-specific credentials, see [Ecosystem Credentials](./ecosystem-credentials.md).

For selective disclosure and proof-only flows, see [ZK Credentials](./zk-credentials.md).