WIP: Add musig support

Cargo.toml

@@ -26,6 +26,7 @@ cli = ["base64-compat", "clap", "fern", "log", "jobserver", "shell-escape"]
 [dependencies]
 bitcoin = { version = "0.32.5", features = [ "std", "serde", "rand", "rand-std" ] }
 secp256k1 = { version = "0.29", features = [ "recovery" ] }
+secp256k1_zkp_musig = { package = "secp256k1-zkp", git = "https://github.com/sanket1729/rust-secp256k1-zkp.git", rev = "0de61c2cc536a58f08822851528a5dfa5968d155" }
 bip39 = { version = "2.1.0", features = [ "all-languages" ] }
 lightning-invoice = { version = "0.32.0", features = [ "std" ] }
 miniscript = { version = "12.3.0", features = ["compiler"] }

src/bin/hal/cmd/mod.rs

@@ -9,6 +9,7 @@ pub mod ln;
 pub mod merkle;
 pub mod message;
 pub mod miniscript;
+pub mod musig;
 pub mod psbt;
 pub mod random;
 pub mod script;
@@ -28,6 +29,7 @@ pub fn subcommands() -> Vec<clap::App<'static, 'static>> {
 		merkle::subcommand(),
 		message::subcommand(),
 		miniscript::subcommand(),
+		musig::subcommand(),
 		psbt::subcommand(),
 		random::subcommand(),
 		script::subcommand(),

src/bin/hal/cmd/musig.rs

@@ -0,0 +1,43 @@
+
+use std::str::FromStr;
+use crate::prelude::*;
+use secp256k1_zkp_musig as zkpmusig;
+
+pub fn subcommand<'a>() -> clap::App<'a, 'a> {
+	cmd::subcommand_group("musig", "use the MuSig2 multisignature protocol")
+		.subcommand(cmd_aggregate())
+}
+
+pub fn execute<'a>(args: &clap::ArgMatches<'a>) {
+	match args.subcommand() {
+		("aggregate", Some(ref m)) => exec_aggregate(&m),
+		(_, _) => unreachable!("clap prints help"),
+	};
+}
+
+fn cmd_aggregate<'a>() -> clap::App<'a, 'a> {
+	cmd::subcommand("aggregate", "aggregate public keys in a MuSig2 compatible way")
+		.arg(args::flag(
+			"ordered", "aggregate in the specified order instead of ordering lexicographically",
+		))
+		.arg(args::arg("pubkeys", "list of public keys in hex").required(true).multiple(true))
+}
+
+fn exec_aggregate<'a>(args: &clap::ArgMatches<'a>) {
+	let mut pks = Vec::with_capacity(2);
+	for arg in args.values_of("pubkeys").need("no pubkeys provided") {
+		let pk = bitcoin::PublicKey::from_str(&arg).unwrap_or_else(|_| {
+			exit!("invalid public key provided: {}", arg);
+		});
+		pks.push(zkpmusig::PublicKey::from_slice(&pk.inner.serialize()).unwrap());
+	}
+
+	if !args.is_present("ordered") {
+		//TODO(stevenroose) is this lexicographically
+		pks.sort_by_key(|k| k.serialize());
+	}
+
+	let secp = zkpmusig::Secp256k1::new();
+	let agg = zkpmusig::MusigKeyAggCache::new(&secp, &pks[..]);
+	print!("{}", agg.agg_pk());
+}

src/bin/hal/main.rs

@@ -141,6 +141,7 @@ fn main() {
 		("merkle", Some(ref m)) => cmd::merkle::execute(&m),
 		("message", Some(ref m)) => cmd::message::execute(&m),
 		("miniscript", Some(ref m)) => cmd::miniscript::execute(&m),
+		("musig", Some(ref m)) => cmd::musig::execute(&m),
 		("psbt", Some(ref m)) => cmd::psbt::execute(&m),
 		("random", Some(ref m)) => cmd::random::execute(&m),
 		("script", Some(ref m)) => cmd::script::execute(&m),