Sidetree Protocol

The Sidetree Protocol is a Layer 2 protocol designed to enable scalable Decentralized Identifier (DID) networks that can operate on top of any existing decentralized anchoring system. This specification, ratified by the Decentralized Identity Foundation, provides a framework for creating open, public, and permissionless DID implementations without requiring special tokens or additional consensus mechanisms.

Key features:

• Enables creation of globally unique, user-controlled identifiers
• Operates without centralized authorities or trusted third parties
• Supports multiple anchoring systems (Bitcoin, Ethereum, etc.)
• Provides deterministic state resolution
• Offers scalable operation batching capabilities

Core Technical Components:

1. Network Architecture:

• Sidetree Nodes that process operations and maintain state
• Content-Addressable Storage (CAS) network for data distribution
• Underlying anchoring system for chronological ordering

2. File Structures:

• Core Index Files containing create, recover, and deactivate operations
• Provisional Index Files containing update operations
• Chunk Files containing operation data
• Proof Files containing cryptographic proofs

3. Operation Types:

• Create - Initial DID creation
• Update - Modification of DID state
• Recover - Recovery of DID control
• Deactivate - Permanent DID deactivation

Technical Specifications:

1. Purpose and Scope:

• Provides a deterministic protocol for DID creation and management
• Enables scalable Layer 2 solutions for existing blockchain systems
• Supports both short-form and long-form DID URI formats

2. Key Technical Requirements:

• Uses JSON Web Signatures (JWS) for operation authentication
• Implements Multihash for content addressing
• Requires Base64URL encoding for data representation
• Supports IPFS as the default CAS protocol

3. Implementation Requirements:

• Must implement specified hashing algorithms (SHA256)
• Must support defined key algorithms (secp256k1)
• Must handle compression (GZIP)
• Must enforce file size limits and validation rules

4. Security Considerations:

• Implements cryptographic commitment schemes
• Provides key rotation mechanisms
• Supports recovery mechanisms
• Includes deactivation capabilities

5. Interoperability Features:

• Compliant with W3C DID Core specification
• Supports multiple anchoring systems
• Enables cross-platform implementation
• Provides standardized REST API

6. Current Status:

• Version 1.0.1 specification
• Multiple active implementations
• Growing ecosystem adoption
• Continued development and refinement

The protocol is particularly notable for its ability to batch multiple operations together, enabling high throughput while maintaining decentralized security properties. This makes it suitable for large-scale DID deployments requiring both performance and security.