npub1xu…g43rm on Nostr: #[cfg(feature = "nostr")] use frost_secp256k1_tr as frost; #[cfg(feature = "nostr")] ...

#[cfg(feature = "nostr")]
use frost_secp256k1_tr as frost;
#[cfg(feature = "nostr")]
use rand::thread_rng;
#[cfg(feature = "nostr")]
use std::collections::BTreeMap;

#[cfg(feature = "nostr")]
fn main() -> Result<(), Box<dyn std::error::Error>> {
let mut rng = thread_rng();
let max_signers = 3;
let min_signers = 2;

////////////////////////////////////////////////////////////////////////////
// Round 0: Key Generation (Trusted Dealer)
////////////////////////////////////////////////////////////////////////////

// In a real P2P setup, you'd use Distributed Key Generation (DKG).
// For local testing/simulations, the trusted dealer is faster.
let (shares, pubkey_package) = frost::keys::generate_with_dealer(
max_signers,
min_signers,
frost::keys::IdentifierList::Default,
&mut rng,
)?;

// Verifying the public key exists
let group_public_key = pubkey_package.verifying_key();
println!("Group Public Key: {:?}", group_public_key);

////////////////////////////////////////////////////////////////////////////
// Round 1: Commitment
////////////////////////////////////////////////////////////////////////////

let message = b"BIP-64MOD Consensus Proposal";
let mut signing_commitments = BTreeMap::new();
let mut participant_nonces = BTreeMap::new();

// Participants 1 and 2 decide to sign
for i in 1..=min_signers {
let identifier = frost::Identifier::try_from(i as u16)?;

// Generate nonces and commitments
let (nonces, commitments) = frost::round1::commit(
shares[&identifier].signing_share(),
&mut rng,
);

signing_commitments.insert(identifier, commitments);
participant_nonces.insert(identifier, nonces);
}

////////////////////////////////////////////////////////////////////////////
// Round 2: Signing
////////////////////////////////////////////////////////////////////////////

let mut signature_shares = BTreeMap::new();
let signing_package = frost::SigningPackage::new(signing_commitments, message);

for i in 1..=min_signers {
let identifier = frost::Identifier::try_from(i as u16)?;
let nonces = &participant_nonces[&identifier];

// Each participant produces a signature share
let key_package: frost::keys::KeyPackage = shares[&identifier].clone().try_into()?;
let share = frost::round2::sign(&signing_package, nonces, &key_package)?;
signature_shares.insert(identifier, share);
}

////////////////////////////////////////////////////////////////////////////
// Finalization: Aggregation
////////////////////////////////////////////////////////////////////////////

let group_signature = frost::aggregate(
&signing_package,
&signature_shares,
&pubkey_package,
)?;

// Verification
group_public_key.verify(message, &group_signature)?;

println!("Threshold signature verified successfully!");
Ok(())
}

#[cfg(not(feature = "nostr"))]
fn main() {
println!("This example requires the 'nostr' feature. Please run with: cargo run --example trusted-dealer --features nostr");
}