Doesn't fully utilize ec's hash2curve module as k256 Scalar doesn't have
FromOkm for some reason. The previously present bigint reduction is
preserved.
Updates ff/group to 0.12.
Premised on https://github.com/cfrg/draft-irtf-cfrg-frost/pull/205 being
merged, as while this Ed25519 is vector compliant, it's technically not
spec compliant due to that conflict.
Given the lack of vectors for k256, it's currently a match of the p256
spec (with a distinct context string), yet p256 is still always used
when testing.
No functional changes have been made to signing, with solely slight API
changes being made.
Technically not actually FROST v5 compatible, due to differing on zero
checks and randomness, yet the vectors do confirm the core algorithm.
For any valid FROST implementation, this will be interoperable if they
can successfully communicate. For any devious FROST implementation, this
will be fingerprintable, yet should still be valid.
Relevant to https://github.com/serai-dex/serai/issues/9 as any curve can
now specify vectors for itself and be tested against them.
Moves the FROST testing curve from k256 to p256. Does not expose p256
despite being compliant. It's not at a point I'm happy with it, notably
regarding hash to curve, and I'm not sure I care to support p256. If it
has value to the larger FROST ecosystem...
Also updates Bulletproofs from C to not be length prefixed, yet rather
have Rust calculate their length.
Corrects an error in key_gen where self was blamed, instead of the
faulty participant.
Saves ~8% during FROST key gen, even with dropping a vartime for a
constant time (as needed to be secure), as the new batch verifier is
used where batch verification previously wasn't. The new multiexp API
itself also offered a very slight performance boost, which may solely be
a measurement error.
Handles most of https://github.com/serai-dex/serai/issues/10. The blame
function isn't binary searched nor randomly sorted yet.
