multisig-rs

A multisig wallet implementation in Rust using secp256k1 for transaction signing and verification. This project explores cryptographic primitives, threshold signatures, and robust error handling in blockchain applications.

Overview

This project implements a multi-signature (multisig) wallet where multiple parties must approve a transaction before it can be executed. It uses the secp256k1 elliptic curve cryptography library for signing and verification, which is the same cryptographic standard used in Bitcoin and Ethereum.

Key Features

• M-of-N Signature Scheme: Configure a wallet requiring M signatures out of N total signers
• Secp256k1 Cryptography: Industry-standard elliptic curve cryptography for secure signing
• Transaction Management: Create, sign, and verify transactions with multiple signatures
• Threshold Signature Support: Only execute transactions when the required threshold is met
• Robust Error Handling: Comprehensive error types using thiserror for better debugging
• Serialization Support: JSON serialization for transactions and wallet state using serde

Architecture

The project is structured into several core modules:

multisig-rs/
├── src/
│   ├── main.rs           # CLI entry point
│   ├── lib.rs            # Library root and module declarations
│   ├── wallet.rs         # MultisigWallet implementation
│   ├── transaction.rs    # Transaction structure and signing logic
│   ├── crypto.rs         # Cryptographic utilities (key generation, signing)
│   └── error.rs          # Custom error types
├── tests/
│   └── integration_tests.rs  # Integration tests
├── Cargo.toml            # Project dependencies
└── README.md             # This file

How It Works

1. Wallet Creation

Create a multisig wallet by specifying:

• N: Total number of signers.
• M: Minimum number of signatures required (threshold).
• Public Keys: List of all authorized signers' public keys.

2. Transaction Proposal

Any authorized signer can propose a transaction containing:

• Recipient address.
• Amount to transfer.
• Optional metadata.

3. Signature Collection

Signers review and sign the proposed transaction:

• Each signature is verified against the authorized public keys.
• Signatures are collected until the threshold M is reached.

4. Transaction Execution

Once M valid signatures are collected:

• The transaction is verified
• If valid, the transaction can be executed.
• If invalid or insufficient signatures, the transaction is rejected.

Cryptographic Primitives

Secp256k1

• Elliptic Curve: secp256k1 (same as Bitcoin/Ethereum).
• Key Generation: Secure random private key generation.
• Signing: ECDSA (Elliptic Curve Digital Signature Algorithm).
• Verification: Public key recovery and signature validation.

Hashing

• SHA-256: Used for transaction hashing before signing.
• Ensures data integrity and prevents tampering

Use Cases

• Corporate Treasury: Require multiple executives to approve large transactions
• DAO Governance: Multi-party approval for fund disbursement
• Escrow Services: Buyer, seller, and arbiter must all agree
• Security: Reduce single point of failure by distributing signing authority

Security Considerations

• Private Key Management: Private keys should never be shared or stored insecurely
• Signature Verification: All signatures are cryptographically verified before acceptance
• Threshold Security: Even if some keys are compromised, funds remain safe if below threshold
• Replay Protection: Each transaction should include unique identifiers to prevent replay attacks

Getting Started

Prerequisites

• Rust 1.70+ (install from rustup.rs)
• Cargo (comes with Rust)

Installation

git clone https://github.com/Cherrypick14/multisig-rs.git
cd multisig-rs
cargo build --release

Running Tests

cargo test

Example Usage

use multisig_rs::{MultisigWallet, Transaction};

// Create a 2-of-3 multisig wallet
let wallet = MultisigWallet::new(2, vec![pubkey1, pubkey2, pubkey3]);

// Create a transaction
let tx = Transaction::new(recipient, amount);

// Sign with first key
let sig1 = tx.sign(&private_key1);
wallet.add_signature(&tx, sig1);

// Sign with second key (reaches threshold)
let sig2 = tx.sign(&private_key2);
wallet.add_signature(&tx, sig2);

// Verify and execute
if wallet.verify_transaction(&tx) {
    wallet.execute_transaction(&tx);
}

Dependencies

• secp256k1: Elliptic curve cryptography
• rand: Secure random number generation
• sha2: SHA-256 hashing
• serde: Serialization/deserialization
• serde_json: JSON support
• thiserror: Error handling

Roadmap

• Project initialization
• Core wallet implementation
• Transaction signing and verification
• CLI interface
• Comprehensive test suite
• Documentation and examples
• Advanced features (time locks, spending limits)

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

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

Acknowledgments

• Bitcoin and Ethereum for secp256k1 standards
• Rust cryptography community
• Multi-signature wallet research and implementations

Contact

For questions or suggestions, please open an issue on GitHub.