Module threshold_ecdsa 

Threshold ECDSA for distributed signature generation.

This module implements a threshold ECDSA signature scheme where a group of n signers can jointly generate an ECDSA-style signature with only t signers participating (t-of-n threshold).

Protocol Overview

1. Setup: Distributed key generation to create key shares
2. Signing Round 1: Each signer generates nonce shares
3. Signing Round 2: Combine nonces and create partial signatures
4. Aggregation: Combine partial signatures into final signature

Example

use chie_crypto::threshold_ecdsa::*;

// Create a 2-of-3 threshold ECDSA setup
let threshold = 2;
let total = 3;

// Generate threshold key shares (in practice, use DKG)
let (group_pubkey, key_shares) = generate_threshold_keys(threshold, total).unwrap();

// Create signers from shares
let signer1 = ThresholdEcdsaSigner::from_share(threshold, total, key_shares[0].1.clone(), key_shares[0].2);
let signer2 = ThresholdEcdsaSigner::from_share(threshold, total, key_shares[1].1.clone(), key_shares[1].2);
let signer3 = ThresholdEcdsaSigner::from_share(threshold, total, key_shares[2].1.clone(), key_shares[2].2);

let message = b"Threshold ECDSA test";

// Signing Round 1: Generate nonce shares (only 2 signers participate)
let nonce1 = signer1.generate_nonce_share();
let nonce2 = signer2.generate_nonce_share();

let nonce_shares = vec![nonce1.public(), nonce2.public()];
let signer_ids = vec![1, 2];

// Signing Round 2: Create partial signatures
let partial1 = signer1.partial_sign(message, &nonce1, &nonce_shares, &signer_ids).unwrap();
let partial2 = signer2.partial_sign(message, &nonce2, &nonce_shares, &signer_ids).unwrap();

// Aggregate signatures
let signature = aggregate_threshold_signatures(&[partial1, partial2], &nonce_shares).unwrap();

// Verify
assert!(verify_threshold_ecdsa(&group_pubkey, message, &signature));

Structs

NonceShare

Nonce share (ephemeral key for signing)

PublicNonceShare

Public nonce share

PublicShare

Public key share

SecretShare

Secret share for a threshold ECDSA signer

ThresholdEcdsaSignature

Final threshold ECDSA signature

ThresholdEcdsaSigner

Threshold ECDSA signer

ThresholdPartialSignature

Partial signature from a signer

Enums

ThresholdEcdsaError

Functions

aggregate_threshold_public_key

Aggregate public key shares into group public key

aggregate_threshold_signatures

Aggregate partial signatures into final signature

generate_threshold_keys

Generate threshold key shares using polynomial secret sharing

verify_threshold_ecdsa

Verify a threshold ECDSA signature

Type Aliases

ThresholdEcdsaResult

ThresholdKeyShares

Type alias for threshold key generation result: (group_pubkey, key_shares)