Peer DID Method Specification

The Peer DID Method Specification is a decentralized identifier standard designed for private, peer-to-peer relationships between parties. Unlike public DID methods that rely on blockchains or central registries, Peer DIDs operate independently of any central source of truth, making them ideal for direct relationships between people, organizations, and things.

The specification defines multiple algorithms for generating and managing these identifiers, with a focus on security, privacy, and efficiency. Peer DIDs are particularly well-suited for scenarios where only the participating parties need to resolve the identifiers, rather than requiring public resolution.

Key differentiating features include:

• Zero transaction costs for creation and maintenance
• Scalability limited only by participating parties
• No central system dependencies
• Reduced privacy concerns due to peer-to-peer nature
• Blockchain-agnostic implementation
• Offline-first capability
• Support for both short-form and long-form identifiers

Purpose and Scope:

• Enable private, secure peer-to-peer relationships using DIDs
• Support both pairwise (2-party) and n-wise (multiple party) relationships
• Provide mechanisms for key management and service endpoints
• Enable offline-capable identity management

Key Technical Specifications:

• Method name prefix: did:peer:
• Multiple numeric algorithms (numalgo) for DID generation:
  • Method 0: Single inception key
  • Method 1: Genesis doc with SHA-256 hash
  • Method 2: Multiple inception keys
  • Method 3: Shortened hash version
  • Method 4: Short/long form combination

Implementation Requirements:

• Support for Base58 encoding
• Implementation of specified generation algorithms
• Local storage for DID documents
• Support for cryptographic key management
• Verification of DID generation integrity

Security Considerations:

• Trust-on-first-use (TOFU) handling
• Proof of Control verification
• Secure key management practices
• Protection against man-in-the-middle attacks
• Entropy requirements for key generation

Interoperability Features:

• Compatible with DIDComm v2
• Support for multiple key types
• Service endpoint definitions
• Verification relationship handling
• Cross-method compatibility considerations

Current Adoption Status:

• Reference implementations available in Python and Java
• Active development and maintenance by the Decentralized Identity Foundation
• Growing adoption in private relationship scenarios
• Integration with various identity management systems