* Initial attempt at Bulletproofs
I don't know why this doesn't work. The generators and hash_cache lines
up without issue. AFAICT, the inner product proof is valid as well, as
are all included formulas.
* Add yinvpow asserts
* Clean code
* Correct bad imports
* Fix the definition of TWO_N
Bulletproofs work now :D
* Tidy up a bit
* fmt + clippy
* Compile a variety of XMR dependencies with optimizations, even under dev
The Rust bulletproof implementation is 8% slower than C right now, under
release. This is acceptable, even if suboptimal. Under debug, they take
a quarter of a second to two seconds though, depending on the amount of
outputs, which justifies this move.
* Remove unnecessary deref in BPs
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
The two-generator limit wasn't required nor beneficial. This does
theoretically optimize FROST, yet not for any current constructions. A
follow up proof which would optimize current constructions has been
noted in #38.
Adds explicit no_std support to the core DLEq proof.
Closes#34.
Removes from_canonical_bytes, which is offered by from_repr, and
from_bytes_mod_order, which frequently leads to security issues.
Removes the pointless Compressed type.
Adds From u8/u16/u32 as they're pleasant.
While all of Serai can be argued as experimental, the DLEq proof is
especially so, as it's lacking any formal proofs over its theory.
Also adds doc(hidden) to the generic DLEqProof, now prefixed with __.
This enabled getting the proof sizes, which are:
- ConciseLinear had a proof size of 44607 bytes
- CompromiseLinear had a proof size of 48765 bytes
- ClassicLinear had a proof size of 56829 bytes
- EfficientLinear had a proof size of 65145 byte
Formatted results from my laptop:
EfficientLinear had a average prove time of 188ms
EfficientLinear had a average verify time of 126ms
CompromiseLinear had a average prove time of 176ms
CompromiseLinear had a average verify time of 141ms
ConciseLinear had a average prove time of 191ms
ConciseLinear had a average verify time of 160ms
ClassicLinear had a average prove time of 214ms
ClassicLinear had a average verify time of 159ms
There is a decent error margin here. Concise is a drop-in replacement
for Classic, in practice *not* theory. Efficient is optimal for
performance, yet largest. Compromise is a middleground.
The batch verified one offers ~23% faster verification. While this
massively refactors for modularity, I'm still not happy with the DLEq
proofs at the top level, nor am I happy with the AOS signatures. I'll
work on cleaning them up more later.
Reduces proof size by 21.5% without notable computational complexity
changes. I wouldn't be surprised if it has minor ones, yet I can't
comment in which way they go without further review.
Bit now verifies it can successfully complete the ring under debug,
slightly increasing debug times.
Few percent faster. Enables accumulating the current bit's point
representation, whereas the blinding keys can't be accumulated. Also
theoretically enables pre-computation of the bit points, removing
hundreds of additions from the proof. When tested, this was less
performant, possibly due to cache/heap allocation.
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.
