SSS Wallet Core

A distributed cryptographic wallet system using Shamir's Secret Sharing (SSS) to securely manage private keys. The system splits a private key into multiple shares and can recover it using only a subset of shares.

Features

• Distributed Key Management: Split private key into 5 shares (recoverable with 3)
• Secure Signing: Sign messages using randomly selected shares
• Signature Verification: ECDSA signature validation
• REST API: Simple HTTP-based API

Quick Start

# Install dependencies
go mod download

# Run server
go run cmd/server/main.go

Server runs on http://localhost:8080

API Endpoints

GET /wallet

Get wallet public key information.

Response:

{
  "x": "1234567890abcdef...",
  "y": "fedcba0987654321..."
}

POST /sign

Sign a message using distributed shares.

Request:

{
  "message": "Hello, World!"
}

Response:

{
  "r": "a1b2c3d4e5f6...",
  "s": "f6e5d4c3b2a1..."
}

POST /verify

Verify a signature.

Request:

{
  "message": "Hello, World!",
  "r": "a1b2c3d4e5f6...",
  "s": "f6e5d4c3b2a1..."
}

Response:

{
  "valid": true
}

Security Features

• Shamir's Secret Sharing: 5 shares with threshold 3
• ECDSA: P-256 curve with SHA-256 hashing
• Random Selection: Different share combinations for each signature
• Fault Tolerance: System remains secure even if some shares are lost

Architecture

sss-wallet-core/
├── cmd/server/main.go    # Application entry point
├── core/                 # Core cryptographic logic
│   ├── keygen.go        # Key generation & splitting
│   ├── sss.go           # Shamir reconstruction
│   ├── sign.go          # ECDSA signing
│   └── verify.go        # Signature verification
└── handlers/            # HTTP request handlers
    ├── wallet.go        # Wallet info handler
    ├── sign.go          # Signing handler
    └── verify.go        # Verification handler

Requirements

• Go 1.24.3+
• Hashicorp Vault library

Use Cases

• Blockchain wallet key management
• Multi-signature systems
• Secure key backup and recovery
• Distributed systems with fault tolerance

License

MIT