Files
serai/crypto/ciphersuite
Luke Parker a141deaf36 Smash the singular Ciphersuite trait into multiple
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`.
2025-09-03 13:50:20 -04:00
..
2025-08-25 10:06:35 -04:00
2025-08-29 05:21:43 -04:00

Ciphersuite

Ciphersuites for elliptic curves premised on ff/group.

This library, except for the not recommended Ed448 ciphersuite, was audited by Cypher Stack in March 2023, culminating in commit 669d2dbffc1dafb82a09d9419ea182667115df06. Any subsequent changes have not undergone auditing.

This library is usable under no_std. The alloc and std features enable reading from the io::Read trait, shimmed by std-shims under alloc.

Secp256k1/P-256

Secp256k1 and P-256 are offered via k256 and p256, two libraries maintained by RustCrypto.

Please see the ciphersuite-kp256 crate for more info.

Ed25519/Ristretto

Ed25519/Ristretto are offered via dalek-ff-group, an ff/group wrapper around curve25519-dalek.

Please see the dalek-ff-group crate for more info.

Ed448

Ed448 is offered via minimal-ed448, an explicitly not recommended, unaudited, incomplete Ed448 implementation, limited to its prime-order subgroup.

Please see the minimal-ed448 crate for more info.