MuSig2RegisterCombinedNonce

MuSig2RegisterCombinedNonce (experimental!) registers a pre-aggregated combined nonce for a signing session. This is an alternative to MuSig2RegisterNonces and is used when a coordinator has already aggregated all individual nonces and wants to distribute the combined nonce to participants.

NOTE: This method is mutually exclusive with MuSig2RegisterNonces for the same session. The MuSig2 BIP is not final yet and therefore this API must be considered to be HIGHLY EXPERIMENTAL and subject to change in upcoming releases. Backward compatibility is not guaranteed!

Source: signrpc/signer.proto

gRPC

rpc MuSig2RegisterCombinedNonce (MuSig2RegisterCombinedNonceRequest) returns (MuSig2RegisterCombinedNonceResponse);

REST

HTTP Method	Path
POST	/v2/signer/musig2/registercombinednonce

Code Samples

gRPC

Javascript

const fs = require('fs');
const grpc = require('@grpc/grpc-js');
const protoLoader = require('@grpc/proto-loader');

const GRPC_HOST = 'localhost:10009'
const MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'
const TLS_PATH = 'LND_DIR/tls.cert'

const loaderOptions = {
  keepCase: true,
  longs: String,
  enums: String,
  defaults: true,
  oneofs: true,
};
const packageDefinition = protoLoader.loadSync(['lightning.proto', 'signrpc/signer.proto'], loaderOptions);
const signrpc = grpc.loadPackageDefinition(packageDefinition).signrpc;
process.env.GRPC_SSL_CIPHER_SUITES = 'HIGH+ECDSA';
const tlsCert = fs.readFileSync(TLS_PATH);
const sslCreds = grpc.credentials.createSsl(tlsCert);
const macaroon = fs.readFileSync(MACAROON_PATH).toString('hex');
const macaroonCreds = grpc.credentials.createFromMetadataGenerator(function(args, callback) {
  let metadata = new grpc.Metadata();
  metadata.add('macaroon', macaroon);
  callback(null, metadata);
});
let creds = grpc.credentials.combineChannelCredentials(sslCreds, macaroonCreds);
let client = new signrpc.Signer(GRPC_HOST, creds);
let request = {
  session_id: <bytes>,
  combined_public_nonce: <bytes>,
};
client.muSig2RegisterCombinedNonce(request, function(err, response) {
  console.log(response);
});
// Console output:
//  {
//  }

Python

import codecs, grpc, os
# Generate the following 2 modules by compiling the signrpc/signer.proto with the grpcio-tools.
# See https://github.com/lightningnetwork/lnd/blob/master/docs/grpc/python.md for instructions.
import signer_pb2 as signrpc, signer_pb2_grpc as signerstub

GRPC_HOST = 'localhost:10009'
MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'
TLS_PATH = 'LND_DIR/tls.cert'

# create macaroon credentials
macaroon = codecs.encode(open(MACAROON_PATH, 'rb').read(), 'hex')
def metadata_callback(context, callback):
  callback([('macaroon', macaroon)], None)
auth_creds = grpc.metadata_call_credentials(metadata_callback)
# create SSL credentials
os.environ['GRPC_SSL_CIPHER_SUITES'] = 'HIGH+ECDSA'
cert = open(TLS_PATH, 'rb').read()
ssl_creds = grpc.ssl_channel_credentials(cert)
# combine macaroon and SSL credentials
combined_creds = grpc.composite_channel_credentials(ssl_creds, auth_creds)
# make the request
channel = grpc.secure_channel(GRPC_HOST, combined_creds)
stub = signerstub.SignerStub(channel)
request = signrpc.MuSig2RegisterCombinedNonceRequest(
  session_id=<bytes>,
  combined_public_nonce=<bytes>,
)
response = stub.MuSig2RegisterCombinedNonce(request)
print(response)
# {
# }

REST

Javascript

const fs = require('fs');
const request = require('request');

const REST_HOST = 'localhost:8080'
const MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'

let requestBody = {
  session_id: <string>, // <bytes> (base64 encoded)
  combined_public_nonce: <string>, // <bytes> (base64 encoded)
};
let options = {
  url: `https://${REST_HOST}/v2/signer/musig2/registercombinednonce`,
  // Work-around for self-signed certificates.
  rejectUnauthorized: false,
  json: true,
  headers: {
    'Grpc-Metadata-macaroon': fs.readFileSync(MACAROON_PATH).toString('hex'),
  },
  form: JSON.stringify(requestBody),
}
request.post(options, function(error, response, body) {
  console.log(body);
});
// Console output:
//  {
//  }

Python

import base64, codecs, json, requests

REST_HOST = 'localhost:8080'
MACAROON_PATH = 'LND_DIR/data/chain/bitcoin/regtest/admin.macaroon'
TLS_PATH = 'LND_DIR/tls.cert'

url = f'https://{REST_HOST}/v2/signer/musig2/registercombinednonce'
macaroon = codecs.encode(open(MACAROON_PATH, 'rb').read(), 'hex')
headers = {'Grpc-Metadata-macaroon': macaroon}
data = {
  'session_id': base64.b64encode(<bytes>),
  'combined_public_nonce': base64.b64encode(<bytes>),
}
r = requests.post(url, headers=headers, data=json.dumps(data), verify=TLS_PATH)
print(r.json())
# {
# }

Shell

# There is no CLI command for this RPC

Messages

signrpc.MuSig2RegisterCombinedNonceRequest

Source: signrpc/signer.proto

Field	gRPC Type	REST Type	REST Placement
session_id The unique ID of the signing session the combined nonce should be registered with.	bytes	string	body
combined_public_nonce The 66-byte combined public nonce that was aggregated externally. This is a concatenation of two 33-byte compressed public keys (R1 || R2).	bytes	string	body

signrpc.MuSig2RegisterCombinedNonceResponse

Source: signrpc/signer.proto

note

This response has no parameters.