Files
serai/crypto/ciphersuite/README.md
Luke Parker 90bc364f9f Replace Ciphersuite::hash_to_F
The prior-present `Ciphersuite::hash_to_F` was a sin. Implementations took a
DST, yet were not require to securely handle it. It was also biased towards the
requirements of `modular-frost` as `ciphersuite` was originally written all
those years ago, when `modular-frost` had needs exceeding what `ff`, `group`
satisfied.

Now, the hash is bound to produce an output which can be converted to a scalar
with `ff::FromUniformBytes`. A new `hash_to_F`, which accepts a single argument
of the value to hash (removing the potential to insecurely handle the DST by
removing the DST entirely). Due to `digest` yielding a `GenericArray`, yet
`FromUniformBytes` taking a `const usize`, the `ciphersuite` crate now defines
a `FromUniformBytes` trait taking an array (then implemented for all satisfiers
of `ff::FromUniformBytes`). In order to get the array type from the
`GenericArray`, the output of the hash, `digest` is updated to the `0.11`
release candidate which moves to `flexible-array` which solves that problem.

The existing, specific `hash_to_F` functions have been moved to `modular-frost`
as necessary.

`flexible-array` itself is patched to a fork due to
https://github.com/RustCrypto/hybrid-array/issues/131.
2025-08-29 05:21:43 -04:00

1.5 KiB

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.