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Update the CLSAG multisig API for TX signing

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This commit is contained in:
Luke Parker
2022-04-30 01:41:05 -04:00
parent d0506e2e9b
commit 22ac5ce3b6
5 changed files with 51 additions and 39 deletions
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43
coins/monero/src/clsag/multisig.rs
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@@ -19,15 +19,15 @@ use frost::{Curve, FrostError, algorithm::Algorithm, sign::ParamsView};
use monero::util::ringct::{Key, Clsag};
use crate::{
random_scalar,
hash_to_point,
frost::{MultisigError, Ed25519, DLEqProof},
key_image,
clsag::{Input, sign_core, verify}
};
pub trait Msg: Clone + Debug {
fn msg(&self, image: EdwardsPoint) -> [u8; 32];
pub trait TransactionData: Clone + Debug {
fn msg(&self) -> [u8; 32];
fn mask_sum(&self) -> Scalar;
}
#[allow(non_snake_case)]
@@ -42,23 +42,23 @@ struct ClsagSignInterim {
#[allow(non_snake_case)]
#[derive(Clone, Debug)]
pub struct Multisig<M: Msg> {
pub struct Multisig<D: TransactionData> {
b: Vec<u8>,
AH: (dfg::EdwardsPoint, dfg::EdwardsPoint),
input: Input,
image: Option<EdwardsPoint>,
msg: M,
data: D,
interim: Option<ClsagSignInterim>
}
impl<M: Msg> Multisig<M> {
impl<D: TransactionData> Multisig<D> {
pub fn new(
input: Input,
msg: M
) -> Result<Multisig<M>, MultisigError> {
data: D
) -> Result<Multisig<D>, MultisigError> {
Ok(
Multisig {
b: vec![],
@@ -67,7 +67,7 @@ impl<M: Msg> Multisig<M> {
input,
image: None,
msg,
data,
interim: None
}
)
@@ -78,7 +78,7 @@ impl<M: Msg> Multisig<M> {
}
}
impl<M: Msg> Algorithm<Ed25519> for Multisig<M> {
impl<D: TransactionData> Algorithm<Ed25519> for Multisig<D> {
type Signature = (Clsag, EdwardsPoint);
// We arguably don't have to commit to at all thanks to xG and yG being committed to, both of
@@ -146,7 +146,7 @@ impl<M: Msg> Algorithm<Ed25519> for Multisig<M> {
// in msg if signing a Transaction, yet this ensures CLSAG takes responsibility for its own
// security boundaries
context.extend(&self.image.unwrap().compress().to_bytes());
context.extend(&self.msg.msg(self.image.unwrap()));
context.extend(&self.data.msg());
context.extend(&self.input.context());
context
}
@@ -171,15 +171,14 @@ impl<M: Msg> Algorithm<Ed25519> for Multisig<M> {
seed.extend(&self.context());
seed.extend(&self.b);
let mut rng = ChaCha12Rng::from_seed(Blake2b512::digest(seed)[0 .. 32].try_into().unwrap());
let mask = random_scalar(&mut rng);
#[allow(non_snake_case)]
let (clsag, c, mu_C, z, mu_P, C_out) = sign_core(
&mut rng,
&self.msg.msg(self.image.unwrap()),
&self.data.msg(),
&self.input,
&self.image.unwrap(),
mask,
self.data.mask_sum(),
nonce_sum.0,
self.AH.0.0
);
@@ -200,7 +199,7 @@ impl<M: Msg> Algorithm<Ed25519> for Multisig<M> {
let mut clsag = interim.clsag.clone();
clsag.s[self.input.i] = Key { key: (sum.0 - interim.s).to_bytes() };
if verify(&clsag, &self.msg.msg(self.image.unwrap()), self.image.unwrap(), &self.input.ring, interim.C_out) {
if verify(&clsag, &self.data.msg(), self.image.unwrap(), &self.input.ring, interim.C_out) {
return Some((clsag, interim.C_out));
}
return None;
@@ -221,13 +220,13 @@ impl<M: Msg> Algorithm<Ed25519> for Multisig<M> {
#[allow(non_snake_case)]
#[derive(Clone, Debug)]
pub struct InputMultisig<M: Msg>(EdwardsPoint, Multisig<M>);
pub struct InputMultisig<D: TransactionData>(EdwardsPoint, Multisig<D>);
impl<M: Msg> InputMultisig<M> {
impl<D: TransactionData> InputMultisig<D> {
pub fn new(
input: Input,
msg: M
) -> Result<InputMultisig<M>, MultisigError> {
msg: D
) -> Result<InputMultisig<D>, MultisigError> {
Ok(InputMultisig(EdwardsPoint::identity(), Multisig::new(input, msg)?))
}
@@ -236,11 +235,11 @@ impl<M: Msg> InputMultisig<M> {
}
}
impl<M: Msg> Algorithm<Ed25519> for InputMultisig<M> {
impl<D: TransactionData> Algorithm<Ed25519> for InputMultisig<D> {
type Signature = (Clsag, EdwardsPoint);
fn addendum_commit_len() -> usize {
32 + Multisig::<M>::addendum_commit_len()
32 + Multisig::<D>::addendum_commit_len()
}
fn preprocess_addendum<R: RngCore + CryptoRng>(
@@ -249,7 +248,7 @@ impl<M: Msg> Algorithm<Ed25519> for InputMultisig<M> {
nonces: &[dfg::Scalar; 2]
) -> Vec<u8> {
let (mut serialized, end) = key_image::generate_share(rng, view);
serialized.extend(Multisig::<M>::preprocess_addendum(rng, view, nonces));
serialized.extend(Multisig::<D>::preprocess_addendum(rng, view, nonces));
serialized.extend(end);
serialized
}