Decentralized Identity System

A robust smart contract implementation for managing decentralized identities, credentials, and zero-knowledge proofs on the Stacks blockchain. This system provides a comprehensive framework for digital identity management with built-in security features, reputation tracking, and recovery mechanisms.

Features

• Identity Management

  • Self-sovereign identity registration
  • Secure identity recovery mechanisms
  • Identity status tracking
  • Configurable recovery addresses

• Credential System

  • Verifiable credential issuance
  • Credential revocation
  • Expiration management
  • Metadata support

• Zero-Knowledge Proofs

  • Proof submission and verification
  • Proof data validation
  • Timestamp tracking
  • Admin-based verification

• Reputation System

  • Configurable reputation scores
  • Administrative score updates
  • Score range validation

Technical Specifications

Constants

• Minimum reputation score: 0
• Maximum reputation score: 1000
• Minimum expiration blocks: 1
• Maximum metadata length: 256 bytes
• Minimum proof size: 64 bytes

Error Codes

ERR-NOT-AUTHORIZED (1000)        - Unauthorized access attempt
ERR-ALREADY-REGISTERED (1001)    - Identity already exists
ERR-NOT-REGISTERED (1002)        - Identity not found
ERR-INVALID-PROOF (1003)         - Invalid or non-existent proof
ERR-INVALID-CREDENTIAL (1004)    - Invalid credential
ERR-EXPIRED-CREDENTIAL (1005)    - Credential has expired
ERR-REVOKED-CREDENTIAL (1006)    - Credential has been revoked
ERR-INVALID-SCORE (1007)         - Invalid reputation score
ERR-INVALID-INPUT (1008)         - Invalid input parameters
ERR-INVALID-EXPIRATION (1009)    - Invalid expiration time
ERR-INVALID-RECOVERY-ADDRESS (1010) - Invalid recovery address
ERR-INVALID-PROOF-DATA (1011)    - Invalid proof data

Usage

Identity Registration

(register-identity
    identity-hash     ;; (buff 32)
    recovery-addr     ;; (optional principal)
)

Credential Management

;; Issue a new credential
(issue-credential
    subject          ;; principal
    claim-hash       ;; (buff 32)
    expiration       ;; uint
    metadata         ;; (string-utf8 256)
)

;; Revoke a credential
(revoke-credential
    issuer           ;; principal
    nonce            ;; uint
)

Zero-Knowledge Proofs

;; Submit a proof
(submit-proof
    proof-hash       ;; (buff 32)
    proof-data       ;; (buff 1024)
)

;; Verify a proof (admin only)
(verify-proof
    proof-hash       ;; (buff 32)
)

Recovery Process

(initiate-recovery
    identity         ;; principal
    new-hash         ;; (buff 32)
)

Security Features

• Input validation for all public functions
• Strict authorization checks
• Prevention of proof hash collisions
• Protected admin functions
• Secure recovery process
• Credential expiration enforcement

Read-Only Functions

• get-identity: Retrieve identity information
• get-credential: Get credential details
• verify-credential: Check credential validity
• get-proof: Retrieve proof information

Administrative Functions

• set-admin: Update contract administrator
• update-reputation: Modify identity reputation scores

Best Practices

1. Always verify credentials before accepting them
2. Set appropriate expiration times for credentials
3. Use strong hash functions for identity and claim hashes
4. Implement additional off-chain verification when necessary
5. Maintain secure storage of private keys and recovery information

Future Improvements

• Integration with DID standards
• Enhanced reputation algorithms
• Multi-signature recovery options
• Credential schema validation
• Enhanced privacy features

License

This project is licensed under the MIT License - see the LICENSE file for details.