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Smash the singular Ciphersuite trait into multiple

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This helps identify where the various functionalities are used, or rather, not
used. The `Ciphersuite` trait present in `patches/ciphersuite`, facilitating
the entire FCMP++ tree, only requires the markers _and_ canonical point
decoding. I've opened a PR to upstream such a trait into `group`
(https://github.com/zkcrypto/group/pull/68).

`WrappedGroup` is still justified for as long as `Group::generator` exists.
Moving `::generator()` to its own trait, on an independent structure (upstream)
would be massively appreciated. @tarcieri also wanted to update from
`fn generator()` to `const GENERATOR`, which would encourage further discussion
on https://github.com/zkcrypto/group/issues/32 and
https://github.com/zkcrypto/group/issues/45, which have been stagnant.

The `Id` trait is occasionally used yet really should be first off the chopping
block.

Finally, `WithPreferredHash` is only actually used around a third of the time,
which more than justifies it being a separate trait.

---

Updates `dalek_ff_group::Scalar` to directly re-export
`curve25519_dalek::Scalar`, as without issue. `dalek_ff_group::RistrettoPoint`
also could be replaced with an export of `curve25519_dalek::RistrettoPoint`,
yet the coordinator relies on how we implemented `Hash` on it for the hell of
it so it isn't worth it at this time. `dalek_ff_group::EdwardsPoint` can't be
replaced for an re-export of `curve25519_dalek::SubgroupPoint` as it doesn't
implement `zeroize`, `subtle` traits within a released, non-yanked version.
Relevance to https://github.com/serai-dex/serai/issues/201 and
https://github.com/dalek-cryptography/curve25519-dalek/issues/811#issuecomment-3247732746.

Also updates the `Ristretto` ciphersuite to prefer `Blake2b-512` over
`SHA2-512`. In order to maintain compliance with FROST's IETF standard,
`modular-frost` defines its own ciphersuite for Ristretto which still uses
`SHA2-512`.
This commit is contained in:
Luke Parker
2025-09-03 12:25:37 -04:00
parent 215e41fdb6
commit a141deaf36
124 changed files with 1003 additions and 1211 deletions
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20
coordinator/tributary/src/transaction.rs
View File

@@ -6,8 +6,8 @@ use rand_core::{RngCore, CryptoRng};
use blake2::{digest::typenum::U32, Digest, Blake2b};
use ciphersuite::{
group::{ff::Field, Group, GroupEncoding},
Ciphersuite,
group::{Group, GroupEncoding},
*,
};
use dalek_ff_group::Ristretto;
use schnorr::SchnorrSignature;
@@ -52,7 +52,7 @@ impl SigningProtocolRound {
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub struct Signed {
/// The signer.
signer: <Ristretto as Ciphersuite>::G,
signer: <Ristretto as WrappedGroup>::G,
/// The signature.
signature: SchnorrSignature<Ristretto>,
}
@@ -73,7 +73,7 @@ impl BorshDeserialize for Signed {
impl Signed {
/// Fetch the signer.
pub(crate) fn signer(&self) -> <Ristretto as Ciphersuite>::G {
pub(crate) fn signer(&self) -> <Ristretto as WrappedGroup>::G {
self.signer
}
@@ -86,10 +86,10 @@ impl Signed {
impl Default for Signed {
fn default() -> Self {
Self {
signer: <Ristretto as Ciphersuite>::G::identity(),
signer: <Ristretto as WrappedGroup>::G::identity(),
signature: SchnorrSignature {
R: <Ristretto as Ciphersuite>::G::identity(),
s: <Ristretto as Ciphersuite>::F::ZERO,
R: <Ristretto as WrappedGroup>::G::identity(),
s: <Ristretto as WrappedGroup>::F::ZERO,
},
}
}
@@ -356,7 +356,7 @@ impl Transaction {
&mut self,
rng: &mut R,
genesis: [u8; 32],
key: &Zeroizing<<Ristretto as Ciphersuite>::F>,
key: &Zeroizing<<Ristretto as WrappedGroup>::F>,
) {
fn signed(tx: &mut Transaction) -> &mut Signed {
#[allow(clippy::match_same_arms)] // This doesn't make semantic sense here
@@ -380,13 +380,13 @@ impl Transaction {
}
// Decide the nonce to sign with
let sig_nonce = Zeroizing::new(<Ristretto as Ciphersuite>::F::random(rng));
let sig_nonce = Zeroizing::new(<Ristretto as WrappedGroup>::F::random(rng));
{
// Set the signer and the nonce
let signed = signed(self);
signed.signer = Ristretto::generator() * key.deref();
signed.signature.R = <Ristretto as Ciphersuite>::generator() * sig_nonce.deref();
signed.signature.R = <Ristretto as WrappedGroup>::generator() * sig_nonce.deref();
}
// Get the signature hash (which now includes `R || A` making it valid as the challenge)