This represents the first breaking change in a new release series,
bumping all crates to the 2024 edition of Rust.
As such, the version numbers of all crates have been incremented to
represent a new prerelease series:
- `curve25519-dalek`: v5.0.0-pre
- `ed25519-dalek`: v3.0.0-pre
- `x25519-dalek`: v3.0.0-pre
Note that this commit isn't intended to cut associated crate releases of
these on crates.io, but is merely bumping the version numbers to denote
there are pending breaking changes.
This commit also includes rustfmt changes which were made as part of the
2024 edition.
Also includes clippy fixes.
* Implementation of `hash_to_field` as defined in the standard
* Implementation of `hash_to_curve` as defined in the standard, by changing the mechanism over which we chose the sign.
* For the point above, had to change the `elligator_encode` to return whether `eps` is a square or not (required for `hash_to_curve`).
* Included test vectors of the draft.
* Included `FieldElement::from_bytes_wide(bytes: &u8; 64])` to reduce integers encoded in 64 bytes.
* curve: extract `AffinePoint` type
Based on discussions about `elliptic-curve` trait impls in #746, and
observing a similar type in `ed448-goldilocks` which inspired this one
(not to mention in all of the @RustCrypto elliptic curve crates), adds
an `AffinePoint` type with `x` and `y` coordinates.
For now, the type is kept out of the public API, and used as an
implementation detail for point compression. However, it's been written
with the intent of eventually stabilizing and exposing it. It's been
marked `pub` so unused functionality doesn't automatically trigger dead
code lints.
Further work could include refactoring point decompression to first
produce an `AffinePoint` and then convert to extended twisted Edwards
coordinates (i.e. `EdwardsPoint`), which is more or less what the
existing `step_1` and `step_2` functions do (`step_1` technically
produces projective coordinates, but `Z` is always set to `ONE`).
* Update curve25519-dalek/src/edwards.rs
* curve: rename `FieldElement*::as_bytes` => `::to_bytes`
Methods named `as_*` should perform a zero-cost borrowing conversion:
https://rust-lang.github.io/api-guidelines/naming.html#ad-hoc-conversions-follow-as_-to_-into_-conventions-c-conv
Methods named `to_*` can perform an expensive owned conversion.
Since the `FieldElement*` types are technically part of the public API
(but feature gated), this also preserves the old names with a
deprecation. We can remove them in the next breaking release.
The same change was also made to the backend `Scalar*` types, however
these types are not a part of the public API.
* curve: add `EdwardsPoint::compress_batch` and `::random`
We've had various requests to implement batch point compression for
`EdwardsPoint`, e.g. #705.
We can leverage `FieldElement::batch_invert` to implement it, which
results in a fairly significant speedup.
The name `EdwardsPoint::compress_batch` has been chosen to match
`RistrettoPoint::double_and_compress_batch`.
For benchmarking, randomized `EdwardsPoint`s have been used. To obtain
these, an inherent `EdwardsPoint::random` has been extracted from the
existing `Group::random` implementation, which uses rejection sampling.
`Group::random` has been updated to call the inherent
`EdwardsPoint::random`. This avoids a `group` dependency just to run the
batch compression benchmarks.
The following benchmark results have been obtained:
edwards benches/EdwardsPoint compression
time: [3.5029 µs 3.5098 µs 3.5171 µs]
edwards benches/Batch EdwardsPoint compression/1
time: [3.6698 µs 3.6758 µs 3.6817 µs]
edwards benches/Batch EdwardsPoint compression/2
time: [3.8410 µs 3.8461 µs 3.8516 µs]
edwards benches/Batch EdwardsPoint compression/4
time: [4.1534 µs 4.1961 µs 4.2558 µs]
edwards benches/Batch EdwardsPoint compression/8
time: [4.8466 µs 4.8533 µs 4.8600 µs]
edwards benches/Batch EdwardsPoint compression/16
time: [6.1216 µs 6.1315 µs 6.1410 µs]
As you can see, it affords a fairly significant speedup, batch
compressing 16 points in less time than the standard point compression
algorithm would take to compress 2 in a row.
* Mark constants::BASEPOINT_ORDER_PRIVATE deprecated from pub API
* Move all BASEPOINT_ORDER use private internally
Co-authored-by: Tony Arcieri <bascule@gmail.com>
* Fix CHANGELOG for 4.1.1
---------
Co-authored-by: Tony Arcieri <bascule@gmail.com>
Adds a lints section to the top of lib.rs with the following:
#![warn(
clippy::unwrap_used,
missing_docs,
rust_2018_idioms,
unused_lifetimes,
unused_qualifications
)]
`warn` is used instead of `deny` to prevent the lints from firing during
local development, however we already configure `-D warnings` in CI so
if any lint fails on checked-in code, it will cause a CI failure.
This commit also fixes or explicitly allows any current violations of
these lints. The main ones were:
- `clippy::unwrap_used`: replaces usages of `unwrap` with `expect`
- `rust_2018_idioms`: no implicit lifetimes, which were present on
usages of `core::fmt::Formatter`
