What is a Verifiable Credential

A Verifiable Credential (VC) is a digital version of a credential—such as an ID card, certificate, diploma, or license—that can be issued, presented, and verified securely using cryptography.

Verifiable Credentials are tamper-proof, privacy-respecting, and designed to work without relying on centralized authorities. They are a core component of decentralized identity systems.

Key Concepts

Issuer: The entity that creates and signs the credential (e.g., a university, government agency, or company).
Holder: The person or organization who receives and stores the credential.
Verifier: The party that checks the authenticity and validity of the credential when it’s presented.

What’s Inside a Verifiable Credential?

A typical VC includes:

Information about the subject (e.g., name, ID number, degree earned)
The DID of the issuer
A cryptographic proof (e.g., digital signature)
The context and type of the credential (e.g., “UniversityDegreeCredential”)

Here’s a simplified example:

{
  "@context": ["https://www.w3.org/2018/credentials/v1"],
  "type": ["VerifiableCredential", "UniversityDegreeCredential"],
  "issuer": "did:example:123",
  "issuanceDate": "2024-01-01T00:00:00Z",
  "credentialSubject": {
    "id": "did:example:456",
    "degree": {
      "type": "BachelorDegree",
      "name": "Bachelor of Science in Computer Science"
    }
  },
  "proof": {
    "type": "Ed25519Signature2018",
    "created": "2024-01-01T00:00:00Z",
    "proofPurpose": "assertionMethod",
    "verificationMethod": "did:example:123#key-1",
    "jws": "eyJhbGciOiJF...etc"
  }
}

Benefits

Tamper-proof: Thanks to digital signatures, any change to the content invalidates the credential.
Privacy-respecting: Selective disclosure allows holders to share only the necessary information.
Instantly verifiable: The verifier can check the signature and issuer DID without contacting the issuer.
Interoperable: Built on open W3C standards and compatible across platforms.

Common Use Cases

Digital ID cards (citizen ID, employee badge)
Diplomas and professional certifications
Age verification and access control
Supply chain compliance credentials
Health passes and medical certificates

Relationship with DIDs

Verifiable Credentials rely on DIDs to identify and verify:

Who issued the credential
Who holds it
Which public keys to use for verification

This creates a trust framework where credentials are both portable and verifiable—without centralized intermediaries.

Let me know if you’d like a visual diagram or flow for this concept, or an explainer tailored for a non-technical audience!