did:3

The did:3 method is a decentralized identifier implementation built natively on the Ceramic Network. This method uses Tile Documents, a fundamental data structure in Ceramic, to create mutable DID documents that can be securely updated over time. Unlike blockchain-based DID methods, did:3 leverages Ceramic's distributed network while using blockchain anchoring only for securing state transitions.

The method supports two versions: 3IDv1 (current) and 3IDv0 (legacy). Both versions enable key management and document updates through Ceramic's stream-based architecture. A key feature is the method's support for secure key rotation, made possible by anchoring updates to blockchain networks, which provides explicit versioning and proof-of-publication at specific block heights.

did:3 is designed with cryptographic agility in mind, supporting multiple key types through multicodec encoding. This allows for easy extension to new cryptographic schemes, including quantum-resistant ones. The method currently supports both secp256k1 and x25519 key types, enabling both authentication and encryption capabilities.

Key features include:

• Deterministic streaming for consistent DID resolution
• Versioned DID documents with blockchain-anchored state transitions
• Flexible key management supporting multiple public key types
• Minimal data synchronization requirements for verification
• Decentralized resolution through the Ceramic Network

Technical Implementation:

1. DID Generation and Structure

• Format: did:3:<StreamId> for v1 or did:3:<cid> for v0
• StreamID follows CIP-59 specification
• Uses multibase encoding for identifiers

2. Resolution Process

1. Extract StreamID from DID
2. Load stream from Ceramic network
3. Retrieve latest anchored commit
4. Convert stream content to DID document
5. Include metadata (creation, updates, version info)

3. Key Management

• Supports multiple public key formats:
  • secp256k1 for authentication
  • x25519 for key agreement
• Keys stored in publicKeys object within stream content
• Encoded using multicodec + multibase(base58btc)

4. Security Features

• Blockchain anchoring for state transitions
• Censorship resistance inherited from Ceramic
• Versioned updates with proof-of-publication
• Deactivation capability through content removal

5. Technology Stack

• Primary: Ceramic Network protocol
• Supporting:
  • IPLD for data structures
  • multicodec for key encoding
  • dag-cbor for content encoding
  • Blockchain networks for anchoring
  • base58btc for key representation