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Back to Knowledge Hub Self-Sovereign Identity

Self-Sovereign
Identity

SSI shifts control of identity from centralized authorities to individuals. Explore the architecture, DID methods, credential workflows, and decentralized trust frameworks that power sovereign identity systems worldwide.

The SSI Model

Self-Sovereign Identity is built on the Issuer-Holder-Verifier model. Instead of a central authority controlling identity data, credentials are issued to individuals who hold them in digital wallets and present them to verifiers on demand — cryptographically signed and privacy-preserving.

This model eliminates the need for every service provider to be a identity provider. Governments issue foundational identity credentials once; individuals reuse them across sectors without the issuer tracking every interaction.

DID Methods Comparison

Method Ledger Key Strength Registry Use Case
did:indy Hyperledger Indy ZKPs, AnonCreds Permissioned Government SSI networks
did:key None Simple, no ledger Inline Peer-to-peer, ephemeral
did:web DNS Web-based, familiar Web domain Enterprise, verifiers
did:cheqd Cheqd Payment rails, DIDs Permissionless Pay-per-use credentials
did:ethr Ethereum Smart contracts Permissionless DeFi, DAO credentials
did:polygon Polygon Scalability, EVM Permissionless High-throughput networks

The Credential Flow

1

Issuance

An issuer (government, bank, university) cryptographically signs a verifiable credential and sends it to the holder's wallet. The credential contains claims about the holder along with the issuer's signature.

2

Storage

The holder stores the credential in their digital wallet. The wallet manages key material, DID documents, and credential storage. The holder has full control over which credentials to share and with whom.

3

Presentation

When a verifier requests proof, the holder presents a verifiable presentation — a subset of claims from one or more credentials. Using selective disclosure and zero-knowledge proofs, only required information is revealed.

4

Verification

The verifier checks the cryptographic signature, validates the DID, checks revocation status, and verifies the presentation satisfies the required criteria. No call-back to the issuer is needed.

Key Protocols & Frameworks

DIDComm

Peer-to-peer messaging protocol for secure DID-to-DID communication. Enables encrypted, authenticated message exchange between identity owners without intermediaries.

AnonCreds

Anonymous credential system based on Camenisch-Lysyanskaya signatures. Enables unlinkable presentations and selective disclosure with zero-knowledge proofs.

OpenID4VC

OpenID Foundation suite of protocols for Verifiable Credential issuance (OpenID4VCI) and presentation (OpenID4VP), bridging OAuth2 flows with VCs.

Trust Over IP

A four-layer architecture model (Network, Governance, Protocol, Application) for organizing decentralized trust infrastructure across technical and human trust layers.

Further Reading