Ensures random functions never return zero. This, combined with a check
commitments aren't 0, causes no serialized elements to be 0.
Also directly reads their vectors.
* Theoretical ed448 impl
* Fixes
* Basic tests
* More efficient scalarmul
Precomputes a table to minimize additions required.
* Add a torsion test
* Split into a constant and variable time backend
The variable time one is still far too slow, at 53s for the tests (~5s a
scalarmul). It should be usable as a PoC though.
* Rename unsafe Ed448
It's not only unworthy of the Serai branding and deserves more clarity
in the name.
* Add wide reduction to ed448
* Add Zeroize to Ed448
* Rename Ed448 group.rs to point.rs
* Minor lint to FROST
* Ed448 ciphersuite with 8032 test vector
* Macro out the backend fields
* Slight efficiency improvement to point decompression
* Disable the multiexp test in FROST for Ed448
* fmt + clippy ed448
* Fix an infinite loop in the constant time ed448 backend
* Add b"chal" to the 8032 context string for Ed448
Successfully tests against proposed vectors for the FROST IETF draft.
* Fix fmt and clippy
* Use a tabled pow algorithm in ed448's const backend
* Slight tweaks to variable time backend
Stop from_repr(MODULUS) from passing.
* Use extended points
Almost two orders of magnitude faster.
* Efficient ed448 doubling
* Remove the variable time backend
With the recent performance improvements, the constant time backend is
now 4x faster than the variable time backend was. While the variable
time backend remains much faster, and the constant time backend is still
slow compared to other libraries, it's sufficiently performant now.
The FROST test, which runs a series of multiexps over the curve, does
take 218.26s while Ristretto takes 1 and secp256k1 takes 4.57s.
While 50x slower than secp256k1 is horrible, it's ~1.5 orders of
magntiude, which is close enough to the desire stated in
https://github.com/serai-dex/serai/issues/108 to meet it.
Largely makes this library safe to use.
* Correct constants in ed448
* Rename unsafe-ed448 to minimal-ed448
Enables all FROST tests against it.
* No longer require the hazmat feature to use ed448
* Remove extraneous as_refs
* Apply Zeroize to nonces used in Bulletproofs
Also makes bit decomposition constant time for a given amount of
outputs.
* Fix nonce reuse for single-signer CLSAG
* Attach Zeroize to most structures in Monero, and ZOnDrop to anything with private data
* Zeroize private keys and nonces
* Merge prepare_outputs and prepare_transactions
* Ensure CLSAG is constant time
* Pass by borrow where needed, bug fixes
The past few commitments have been one in-progress chunk which I've
broken up as best read.
* Add Zeroize to FROST structs
Still needs to zeroize internally, yet next step. Not quite as
aggressive as Monero, partially due to the limitations of HashMaps,
partially due to less concern about metadata, yet does still delete a
few smaller items of metadata (group key, context string...).
* Remove Zeroize from most Monero multisig structs
These structs largely didn't have private data, just fields with private
data, yet those fields implemented ZeroizeOnDrop making them already
covered. While there is still traces of the transaction left in RAM,
fully purging that was never the intent.
* Use Zeroize within dleq
bitvec doesn't offer Zeroize, so a manual zeroing has been implemented.
* Use Zeroize for random_nonce
It isn't perfect, due to the inability to zeroize the digest, and due to
kp256 requiring a few transformations. It does the best it can though.
Does move the per-curve random_nonce to a provided one, which is allowed
as of https://github.com/cfrg/draft-irtf-cfrg-frost/pull/231.
* Use Zeroize on FROST keygen/signing
* Zeroize constant time multiexp.
* Correct when FROST keygen zeroizes
* Move the FROST keys Arc into FrostKeys
Reduces amount of instances in memory.
* Manually implement Debug for FrostCore to not leak the secret share
* Misc bug fixes
* clippy + multiexp test bug fixes
* Correct FROST key gen share summation
It leaked our own share for ourself.
* Fix cross-group DLEq tests
Currently intended to be done with:
cargo clippy --features "recommended merlin batch serialize experimental
ed25519 ristretto p256 secp256k1 multisig" -- -A clippy::type_complexity
-A dead_code
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.
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.
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.
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.
Adds helper functions to verify and, on failure, blame, which move an
unwrap from callers into multiexp where it's guaranteed to be safe and
easily verified to be proper.
Closes https://github.com/serai-dex/serai/issues/10.
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.
