* Vendor import unsafe_target_features as curve25519-dalek-derive
Co-authored-by: Jan Bujak <jan@parity.io>
* Remove feature gates from avx2/ifma
* Add buildtime compile diagnostics about backend selection
* Add build script tests
* Documentation changes
* Disable simd related features unless simd was determined via build
* Add note and test about the override warning when unsuccesful
* Reduce complexity in build gating via compile_error
---------
Co-authored-by: Jan Bujak <jan@parity.io>
Co-authored-by: Michael Rosenberg <michael@mrosenberg.pub>
* Replace `unwrap_u8` with `into`
Leverages the `From<Choice>` impl for `bool` where applicable instead,
which results in clearer logic which more closely matches `bool`.
* Remove dependency on `packed_simd`
* Support SIMD on stable Rust
* Move `packed_simd.rs` to `vector` module
* Add comment header to `packed_simd.rs`
* Initialize SIMD registers using intrinsics instead of `transmute`
* Use a splat inside of `unpack_pair`
* Update README: the AVX2 backend now works on stable Rust
* Add a CI job to also build the AVX2 SIMD backend on Rust stable
* Added SIMD MSRV test
* Removed Scalar::{from_bits, from_bytes_clamped}; all constructible scalars are now reduced mod l
* Made Scalar::reduce() not pub; fixed test warning
* Added benches for scalar add/sub/mul
* Docs
* Added EdwardsPoint::mul_base_clamped and gated Scalar::from_bits behind legacy_compatibility
* Added unit test for Mul impl on unreduced Scalars
* Added Montgomery::mul_base_clamped
* Added BasepointTable::mul_base_clamped
* Removed invalid scalar arithmetic test; this functionality is no longer supported
* Made clamp_integer() const
* Updated readme and changelog
* Added BasepointTable::mul_base_clamped to tests
* Added proper deprecation notice to Scalar::from_bits; added legacy_compatibility to Makefile and docsrs flags
* Fixes cfg with target from env
* Derive cleanup
* Default to curve25519_dalek_bits="32" on unknown target
* Give out warning (thanks @jcape)
Co-authored-by: ryan <ryankurte@users.noreply.github.com>
Co-authored-by: James Cape <james@mobilecoin.com>
* Fixed-based Montgomery scalar multiplication
Adds `MontgomeryPoint::mul_base` as an API for fixed-base scalar
multiplication which allows for potential future optimizations.
As a baseline implementation, it uses the variable base scalar
multiplication implementation.
This follows the existing `EdwardsPoint::mul_base` and
`RistrettoPoint::mul_base` APIs.
* Added Montgomery mul_base bench
* Switched MontgomeryPoint::mul_base to use EdwardsPoint::mul_base
---------
Co-authored-by: Michael Rosenberg <michael@mrosenberg.pub>
Re-exports the following commonly used types from their respective
modules to the toplevel of the crate, which makes them easier to access:
- `EdwardsPoint`
- `MontgomeryPoint`
- `RistrettoPoint`
- `Scalar`
The `from_slice` methods on `CompressedEdwardsY` and
`CompressedRistretto` both previously panicked if the slice was the
wrong length.
This changes them to be fallible, returning `TryFromSliceError` in the
event the slice is the wrong length.
It also adds a `TryFrom<&[u8]>` impl for each of these types which calls
the corresponding `from_slice` method.
This is the name we adopted for a similar feature in @RustCrypto.
It's a bit less jargony and also leaves the door open in the future to
other types of precomputed tables.
* Add `basepoint-tables` crate feature
Feature-gates the inclusion of basepoint tables under a
`basepoint-tables` feature, with the goal of reducing code size for e.g.
embedded applications.
* Add `mul_base` method to `EdwardsPoint` and `RistrettoPoint`
Provides fixed-base scalar multiplication which optionally uses
precomputed basepoint tables when the `basepoint-tables` feature is
enabled, providing 4X better performance.
Falls back on variable-base scalar multiplication in the event the
feature is disabled.
Co-authored-by: Michael Rosenberg <michael@mrosenberg.pub>
* Make basepoint table constants static references
This ensures they have a fixed address and aren't duplicated across
compilation units.
Since they were already always borrowed, this changes the static values
to be `&'static` addresses to ensure they're always borrowed rather than
potentially copied.
* rustfmt
The recommendation to set this has been removed from the Rust API
guidelines:
https://github.com/rust-lang/api-guidelines/pull/230
It used to be used by docs.rs, but docs.rs now unconditionally sets the
`--extern-html-root-url` parameter of rustdoc which overrides it, making
it no longer needed and superfluous.
We currently don't have any checks that this crate builds on a `no_std`
target.
While `curve25519-dalek` itself doesn't link `std`, it uses dependencies
which could potentially link `std`, so it's important to have a job to
check that the crate builds on a `no_std` target to ensure feature
activation doesn't accidentally flip on the `std` feature of one of
those dependencies unintentionally.
This adds a job which checks the crate builds on a `thumbv7em-none-eabi`
target which has no `std` implementation.
Previously `alloc` implicitly activated `zeroize` via `zeroize/alloc`.
This commit switches to weak feature activation as added in Rust 1.60,
only activating `zeroize/alloc` if the `zeroize` dependency is
explicitly activated (which it is by default).
* Make `zeroize` an optional dependency
The `zeroize` crate provides a defense against memory read oracles which
typically arise from memory unsafety.
Pure Rust programs may not benefit from `zeroize`, and in certain cases
the unsafe code used by `zeroize` may be more concerning.
This commit makes `zeroize` into an optional feature so users may elect
to disable it if they so desire.
* Added zeroize feature flag to README
Co-authored-by: Michael Rosenberg <michael@mrosenberg.pub>
