Skip to content
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

FROST cfrg spec #119

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

FROST cfrg spec #119

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
36 changes: 20 additions & 16 deletions schnorr_fun/src/frost.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,8 @@
//! # proofs_of_possession.clone(),
//! # )
//! # .unwrap();
//! // signing parties must use a common set of nonces when creating signature shares
//! // signing parties must use a common set of nonces when creating signature shares.
//! // nonces can be derived from a session id that use includes publicly known values.
//! let verification_shares_bytes: Vec<_> = frost_key
//! .verification_shares()
//! .map(|share| share.to_bytes())
Expand Down Expand Up @@ -133,9 +134,9 @@ impl<H: Tagged, NG: AddTag + Clone> Frost<H, NG> {
/// Generate a new Frost context from a Schnorr context.
pub fn new(schnorr: Schnorr<H, NG>) -> Self {
Self {
schnorr: schnorr.clone(),
binding_hash: H::default().tagged(b"frost/binding"),
keygen_id_hash: H::default().tagged(b"frost/keygenid"),
schnorr,
binding_hash: H::default().tagged(b"FROST/noncecoef"),
keygen_id_hash: H::default().tagged(b"FROST/keygenid"),
}
}
}
Expand Down Expand Up @@ -603,8 +604,6 @@ impl<H: Digest<OutputSize = U32> + Clone, NG> Frost<H, NG> {
.ok_or(NewKeyGenError::ZeroFrostKey)?;

let mut keygen_hash = self.keygen_id_hash.clone();
keygen_hash.update((len_first_poly as u32).to_be_bytes());
keygen_hash.update((point_polys.len() as u32).to_be_bytes());
for poly in &point_polys {
for point in poly.0.iter() {
keygen_hash.update(point.to_bytes());
Expand Down Expand Up @@ -747,8 +746,11 @@ impl<H: Digest<OutputSize = U32> + Clone, NG> Frost<H, NG> {
nonces: Vec<(u32, Nonce)>,
message: Message,
) -> SignSession {
let mut nonce_map: BTreeMap<_, _> =
nonces.into_iter().map(|(i, nonce)| (i, nonce)).collect();
let mut nonce_map: BTreeMap<_, _> = nonces
.clone()
.into_iter()
.map(|(i, nonce)| (i, nonce))
.collect();

let agg_nonce_jac: [Point<NonNormal, Public, Zero>; 2] =
nonce_map
Expand All @@ -770,14 +772,15 @@ impl<H: Digest<OutputSize = U32> + Clone, NG> Frost<H, NG> {
.unwrap_or_else(|| G.clone().normalize()),
];

let binding_coeff = Scalar::from_hash(
self.binding_hash
.clone()
.add(agg_nonce_points[0])
.add(agg_nonce_points[1])
.add(frost_key.public_key())
.add(message),
);
// encode group commitment
let mut hash = self.binding_hash.clone();
for (i, nonce) in nonces {
hash = hash.add(i as u8).add(nonce.0[0]).add(nonce.0[1]);
}

hash = hash.add(message);
let binding_coeff = Scalar::from_hash(hash);

let (agg_nonce, nonces_need_negation) =
g!({ agg_nonce_points[0] } + binding_coeff * { agg_nonce_points[1] })
.normalize()
Expand Down Expand Up @@ -969,6 +972,7 @@ mod test {
Scalar::from_non_zero_u32(NonZeroU32::new(i*j)
.expect("starts from 1")))
.collect();

scalar_polys.push(ScalarPoly::new(scalar_poly));
}
let point_polys: Vec<PointPoly> = scalar_polys.iter().map(|sp| sp.to_point_poly()).collect();
Expand Down