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>
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.
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>
This is a convenience/marker trait for types which impl `CryptoRng` +
`RngCore` which makes the type signatures a little more readable.
It was introduced in `rand_core` v0.6.4 (now pinned as the minimum
version)
build.rs was using cfg(target) but it has to evaluate this from env TARGET
as build.rs cfg(target) in build context is the builder host and not the target.
This change fixes curve25519_dalek_bits lottery to determine the correct
automatic curve25119_dalek_bits with the help of platforms crate.
As discussed in #456 this also prepares for well known defaults for wasm and
arm serial backend via cfg(curve25519_dalek_bits = "64")
If the wasm32 or armv7 are going to be u64 serial by default these will be
followed up on later.
Crate features are intended to be additive, whereas only 1-of-N possible
backends can be selected.
Features can also be activated by transitive dependencies, which leads
to a problem of different dependences selecting conflicting backends.
Using `--cfg` instead moves all backend selection control to the
toplevel executable.
This commit switches to the following RUSTFLAGS to enable backends:
- `--cfg curve25519_dalek_backend="fiat"`: uses `fiat-crypto`
- `--cfg curve25519_dalek_backend="simd"`: uses nightly-only SIMD
* Restructure README and CHANGELOG
* Explain semver policy
* Specify feature flags and backends more explicitly
* Remove nightly from the CI bc that didn't belong there
* Add @pinkforest to thankyou list
Co-authored-by: pinkforest <36498018+pinkforest@users.noreply.github.com>
As proposed in #442 this makes `digest` an
optional feature that is not covered by the
SemVer public API stability guarantees.
Co-authored-by: Michael Rosenberg <michael@mrosenberg.pub>
As proposed in #442 this makes `rand_core` an
optional feature that is not covered by the
SemVer public API stability guarantees.
Co-authored-by: Michael Rosenberg <michael@mrosenberg.pub>
As proposed in #414, this commit changes the backend selection approach,
introspecting `target_pointer_width` to select `u32_backend` vs
`u64_backend` (or `fiat_u32_backend`/`fiat_u64_backend` if the
`fiat_backend` feature is enabled).
This helps eliminate the use of non-additive features, and also the
rather confusing errors that happen if multiple backends are selected
(i.e. thousands of lines of rustc errors).
The selection logic checks if `target_pointer_width = "64"` and uses the
64-bit backend, or falls back to the 32-bit backend otherwise. This
means the crate will always have a valid backend regardless of the
pointer width, although there may be odd edge cases for exotic platforms
which would optimally use the 64-bit backend but have a non-"64" target
pointer width for whatever reason. We can handle those cases as they
come up.
Renames fiat backend directory to fiat_u64 and does the additional plumbing required to make fiat_{u32, u64}_backend equal alternatives.
Adds a few comments.
