Instead of having if statements for the bits, it now has constant time
ops. While there are still if statements guiding the proof itself, they
aren't dependent on the data within.
Relies on the ff/group API, instead of the custom Curve type.
Also removes GENERATOR_TABLE, only used by dalek, as we should provide
our own API for that over ff/group instead. This slows down the FROST
tests, under debug, by about 0.2-0.3s. Ed25519 and Ristretto together
take ~2.15 seconds now.
This does reduce the strength of the challenges to that of the weaker
field, yet that doesn't have any impact on whether or not this is ZK due
to the key being shared across fields.
Saves ~8kb.
Closes https://github.com/serai-dex/serai/issues/17 by using the
PrimeFieldBits API to do so.
Should greatly speed up small batches, along with batches in the
hundreds. Saves almost a full second on the cross-group DLEq proof.
While Serai only needs the simple DLEq which was already present under
monero, this migrates the implementation of the cross-group DLEq I
maintain into Serai. This was to have full access to the ecosystem of
libraries built under Serai while also ensuring support for it.
The cross_group curve, which is extremely experimental, is feature
flagged off. So is the built in serialization functionality, as this
should be possible to make nostd once const generics are full featured,
yet the implemented serialization adds the additional barrier of
std::io.
Increases usage of standardization while expanding dalek_ff_group.
Closes https://github.com/serai-dex/serai/issues/26 by moving
dfg::EdwardsPoint to only be for the prime subgroup.
Collisions were possible depending on static label substrings. Now,
labels are prefixed by their length to prevent this from being possible.
All variables are also flagged by their type, preventing other potential
conflicts.
Updates how change outputs are handled, with a far more logical
construction offering greater flexibility.
prepare_outputs can not longer error. SignaableTransaction::new will.
Payments weren't properly selected, as it'd drain a sequential series
instead of the specified set, and inputs had a memory condition Rust
couldn't prove was safe.
Modifies FROST behavior so group_key has the offset applied regardless
of if view was called. The unaltered secret_share and
verification_shares (as they have differing values depending on the
signing set) are no longer publicly accessible.
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.
