Digital Credentials Explained in Simple Terms

A digital credential is like a digital version of a physical document, such as a diploma, ID card, or certificate, that proves something about you or your achievements. It’s stored electronically, often on your phone or computer, and can be shared easily and securely.

Here’s how it works in everyday life:

• Official and Trustworthy: A digital credential is issued by a trusted organization, like a school, employer, or government. It’s designed so no one can fake it.

• Easy to Share: You can send it via email, a QR code, or an app to prove something, like showing you have a degree to a job recruiter.

• Private and Secure: You control what you share, and the credential is protected so it can’t be stolen or altered.

• Convenient: Instead of carrying paper documents, you have all your credentials in one place, like a digital wallet on your phone.

For example, a digital credential could be a badge proving you completed an online course, a driver’s license on your phone, or a ticket to an event. It’s like having a super secure, digital version of your important papers that you can use anytime, anywhere.

Digital Credentials Explained in Technical Terms

A digital credential is a structured, electronically stored representation of a claim or qualification about a subject (e.g., an individual, organization, or entity), typically issued, stored, and verified using cryptographic and digital technologies. Digital credentials often align with standards like the W3C Verifiable Credentials Data Model and are integral to decentralized identity, self-sovereign identity (SSI), and secure data exchange systems. They are commonly implemented as Verifiable Credentials (VCs) but can also include simpler formats like digital badges or certificates.

Key Components of Digital Credentials

1. Data Structure:

   • A digital credential is typically a JSON, JSON-LD, or XML document containing:

     • Metadata: Details like issuer, issuance date, expiration, and credential type.

     • Claims: Assertions about the subject (e.g., “Bob earned a Project Management Certification”).

     • Proof Mechanism: A cryptographic signature (e.g., RSA, ECDSA) or hash to ensure authenticity and integrity.

   • Example (simplified Verifiable Credential in JSON):

     {
       "@context": ["https://www.w3.org/2018/credentials/v1"],
       "id": "urn:uuid:abcd-1234",
       "type": ["VerifiableCredential", "CertificationCredential"],
       "issuer": "did:example:certissuer",
       "issuanceDate": "2024-06-01T00:00:00Z",
       "credentialSubject": {
         "id": "did:example:bob",
         "certification": {
           "name": "Project Management Professional",
           "level": "Advanced"
         }
       },
       "proof": {
         "type": "Ed25519Signature2020",
         "created": "2024-06-01T00:00:00Z",
         "proofValue": "z3x4y5..."
       }
     }

2. Issuance and Verification:

   • Issuer: An entity (e.g., university, employer, or certification body) creates the credential, signs it with a private key, and delivers it to the subject via a secure channel (e.g., digital wallet, email).

   • Verification: A verifier (e.g., employer, service provider) checks the credential’s authenticity by validating the issuer’s digital signature using the corresponding public key, often retrieved via a Decentralized Identifier (DID) or a public registry.

   • Verification may also involve checking revocation status (e.g., via a blockchain or centralized registry).

3. Decentralized Identifiers (DIDs) (Optional):

   • In advanced implementations, digital credentials use DIDs (e.g., did:ethr:0xabc...) to uniquely identify issuers and subjects without relying on centralized authorities.

   • DIDs resolve to DID Documents containing public keys and endpoints for verification.

4. Storage and Management:

   • Digital credentials are stored in a digital wallet (e.g., mobile apps like Microsoft Authenticator, Trinsic, or open-source SSI wallets), which manages credentials, keys, and sharing protocols.

   • Simpler credentials (e.g., digital badges) may be stored as PDFs, images, or proprietary formats in platforms like Credly or Badgr.

5. Cryptographic Security:

   • Credentials are protected using cryptographic techniques like digital signatures or hashes to prevent tampering.

   • Advanced credentials may incorporate Zero-Knowledge Proofs (ZKPs) for selective disclosure, allowing the subject to prove specific attributes (e.g., “I have a valid license”) without revealing the entire credential.

Workflow of Digital Credentials

1. Issuance: The issuer generates the credential, signs it, and sends it to the subject’s wallet or designated storage.

2. Storage: The subject stores the credential in a secure digital wallet or platform, controlling access via private keys or authentication.

3. Presentation: The subject shares the credential (or a subset of its data) with a verifier, often as a Verifiable Presentation (a signed wrapper for VCs) or a simpler format like a PDF or QR code.

4. Verification: The verifier validates the credential’s signature, integrity, and revocation status, ensuring it’s legitimate and current.

Standards and Formats

• W3C Verifiable Credentials: A standardized model for interoperable, cryptographically secure credentials.

• Open Badges: A standard (by IMS Global) for digital badges, often used for education and professional achievements.

• eIDAS: European framework for electronic identification and trust services, supporting digital credentials for identity and signatures.

• Proprietary Formats: Some platforms (e.g., Credly, Certifier) use custom formats for badges or certificates, often less interoperable.

Technologies

• Blockchain/Distributed Ledgers: Used for DID resolution, revocation registries, or anchoring credentials (e.g., Ethereum, Hyperledger Indy).

• Cryptography: Digital signatures (e.g., Ed25519), ZKPs (e.g., zk-SNARKs), and hash functions (e.g., SHA-256).

• Protocols: DIDComm, OpenID Connect, or OAuth 2.0 for secure credential exchange.

Use Cases

• Education: Digital diplomas or course certificates (e.g., MIT’s Blockcerts).

• Professional Certifications: Badges for skills or licenses (e.g., PMP, Cisco certifications).

• Identity: Digital IDs or passports for online authentication.

• Access Control: Event tickets or membership passes.

• Compliance: Proof of regulatory compliance (e.g., KYC documents).

Benefits

• Security: Cryptographic protections prevent forgery and tampering.

• Portability: Credentials are easily stored and shared digitally.

• Privacy: Selective disclosure (in advanced systems) limits shared data.

• Efficiency: Instant issuance and verification reduce manual processes.

Challenges

• Interoperability: Proprietary formats may not work across platforms.

• User Experience: Managing wallets or keys can be complex for non-technical users.

• Adoption: Requires issuers, verifiers, and users to adopt compatible systems.

• Revocation: Ensuring credentials can be invalidated if needed (e.g., a revoked license).

In summary, digital credentials are electronically issued, cryptographically secured representations of claims or qualifications, ranging from simple badges to complex VCs. They enable secure, efficient, and user-controlled sharing of verified information in digital ecosystems.

Until next time,
Verified Credentials