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Lint FROST key gen and optimize sign for the success path

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This commit is contained in:
Luke Parker
2022-05-30 01:46:30 -04:00
parent 5a1f273cd5
commit 614badfef7
2 changed files with 51 additions and 43 deletions
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24
crypto/frost/src/sign.rs
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@@ -4,7 +4,6 @@ use std::{rc::Rc, collections::HashMap};
use rand_core::{RngCore, CryptoRng};
use ff::Field;
use group::Group;
use transcript::Transcript;
@@ -99,7 +98,8 @@ fn preprocess<R: RngCore + CryptoRng, C: Curve, A: Algorithm<C>>(
#[allow(non_snake_case)]
struct Package<C: Curve> {
Ris: HashMap<u16, C::G>,
B: HashMap<u16, [C::G; 2]>,
binding: C::F,
R: C::G,
share: Vec<u8>
}
@@ -170,16 +170,9 @@ fn sign_with_share<C: Curve, A: Algorithm<C>>(
}
#[allow(non_snake_case)]
let mut Ris = HashMap::with_capacity(params.view.included.len());
#[allow(non_snake_case)]
let mut R = C::G::identity();
for l in &params.view.included {
#[allow(non_snake_case)]
let this_R = B[l][0] + (B[l][1] * binding);
Ris.insert(*l, this_R);
R += this_R;
}
let R = {
B.values().map(|B| B[0]).sum::<C::G>() + (B.values().map(|B| B[1]).sum::<C::G>() * binding)
};
let share = C::F_to_bytes(
&params.algorithm.sign_share(
&params.view,
@@ -190,7 +183,7 @@ fn sign_with_share<C: Curve, A: Algorithm<C>>(
)
);
Ok((Package { Ris, R, share: share.clone() }, share))
Ok((Package { B, binding, R, share: share.clone() }, share))
}
// This doesn't check the signing set is as expected and unexpected changes can cause false blames
@@ -220,11 +213,12 @@ fn complete<C: Curve, A: Algorithm<C>>(
return Ok(res);
}
// Find out who misbehaved
// Find out who misbehaved. It may be beneficial to randomly sort this to have detection be
// within n / 2 on average, and not gameable to n, though that should be minor
for l in &sign_params.view.included {
if !sign_params.algorithm.verify_share(
sign_params.view.verification_share(*l),
sign.Ris[l],
sign.B[l][0] + (sign.B[l][1] * sign.binding),
responses[l]
) {
Err(FrostError::InvalidShare(*l))?;