Skip to content

[PoC] Add processing of MuSig2 fields #127

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
bigspider wants to merge 1 commit into
base: master
Choose a base branch
from
Draft

[PoC] Add processing of MuSig2 fields #127

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
48 changes: 45 additions & 3 deletions src/ledger.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6,10 +6,10 @@ use std::net::{IpAddr, Ipv4Addr, SocketAddr};
use async_trait::async_trait;
use bitcoin::{
bip32::{DerivationPath, Fingerprint, Xpub},
psbt::Psbt,
psbt::{raw, Psbt},
};
use ledger_bitcoin_client::psbt::PartialSignature;
use ledger_bitcoin_client::SignPsbtYieldedObject;
use ledger_bitcoin_client::{MusigPartialSignature, MusigPubNonce, SignPsbtYieldedObject};

use ledger_apdu::APDUAnswer;
use ledger_transport_hidapi::TransportNativeHID;
Expand Down Expand Up @@ -188,7 +188,17 @@ impl<T: Transport + Sync + Send> HWI for Ledger<T> {
input.tap_key_sig = Some(sig);
}
},
_ => {} // Ignore MuSig2 and unknown payloads
SignPsbtYieldedObject::MusigPubNonce(nonce) => {
let key = musig2_pub_nonce_key(&nonce);
input.unknown.insert(key, nonce.pubnonce.to_vec());
}
SignPsbtYieldedObject::MusigPartialSignature(partial) => {
let key = musig2_partial_sig_key(&partial);
input
.unknown
.insert(key, partial.partial_signature.to_vec());
}
_ => {} // Ignore unknown payloads
}
}
Ok(())
Expand All @@ -199,6 +209,38 @@ impl<T: Transport + Sync + Send> HWI for Ledger<T> {
}
}

/// rust-bitcoin's PSBT implementation does not support musig2 fields,
/// so we encode them as unknown fields, until support is added.
/// BIP-373: PSBT_IN_MUSIG2_PUB_NONCE = 0x1b
/// Key: {0x1b}|{33-byte participant_pubkey}|{33-byte aggregate_pubkey}[|{32-byte tapleaf_hash}]
fn musig2_pub_nonce_key(nonce: &MusigPubNonce) -> raw::Key {
let mut key_data = Vec::with_capacity(66 + 32);
key_data.extend_from_slice(&nonce.participant_pubkey.to_bytes());
key_data.extend_from_slice(&nonce.aggregate_pubkey.to_bytes());
if let Some(tapleaf_hash) = nonce.tapleaf_hash {
key_data.extend_from_slice(tapleaf_hash.as_ref());
}
raw::Key {
type_value: 0x1b,
key: key_data,
}
}

/// BIP-373: PSBT_IN_MUSIG2_PARTIAL_SIG = 0x1c
/// Key: {0x1c}|{33-byte participant_pubkey}|{33-byte aggregate_pubkey}[|{32-byte tapleaf_hash}]
fn musig2_partial_sig_key(sig: &MusigPartialSignature) -> raw::Key {
let mut key_data = Vec::with_capacity(66 + 32);
key_data.extend_from_slice(&sig.participant_pubkey.to_bytes());
key_data.extend_from_slice(&sig.aggregate_pubkey.to_bytes());
if let Some(tapleaf_hash) = sig.tapleaf_hash {
key_data.extend_from_slice(tapleaf_hash.as_ref());
}
raw::Key {
type_value: 0x1c,
key: key_data,
}
}

fn key_string_from_parts(fg: Fingerprint, path: DerivationPath, xpub: Xpub) -> String {
format!(
"[{}/{}]{}",
Expand Down
Loading