pasta_curves

Fixed

• Fix a bug on 32-bit platforms that could cause the square root implementation to return an incorrect result.
• The sqrt-table feature now works without std and only requires alloc.

Added

• serde feature flag, which enables Serde compatibility to the crate types. Field elements and points are serialized to their canonical byte encoding (encoded as hexadecimal if the data format is human readable).

Changed

• Migrated to ff 0.13, group 0.13, ec-gpu 0.2.
• pasta_curves::arithmetic:
  • FieldExt bounds on associated types of CurveExt and CurveAffine have been replaced by bounds on ff::WithSmallOrderMulGroup<3> (and Ord in the case of CurveExt).
• pasta_curves::hashtocurve:
  • FieldExt bounds on the module functions have been replaced by equivalent ff trait bounds.

Removed

• pasta_curves::arithmetic:
  • FieldExt (use ff::PrimeField or ff::WithSmallOrderMulGroup instead).
  • Group
  • SqrtRatio (use ff::Field::{sqrt_ratio, sqrt_alt} instead).
  • SqrtTables (from public API, as it isn't suitable for generic usage).

Added

• uninline-portable feature flag, which disables inlining of some functions. This is useful for tiny microchips (such as ARM Cortex-M0), where inlining can hurt performance and blow up binary size.

Changed

• MSRV is now 1.56.0.
• Migrated to ff 0.12, group 0.12.

Added

• gpu feature flag, which exposes implementations of the GpuField trait from the ec-gpu crate for pasta_curves::{Fp, Fq}. This flag will eventually control all GPU functionality.
• repr-c feature flag, which helps to facilitate usage of this crate's types across FFI by conditionally adding repr(C) attribute to point structures.
• pasta_curves::arithmetic::Coordinates::from_xy

Changed

• pasta_curves::{Fp, Fq} are now declared as repr(transparent), to enable their use across FFI. They remain opaque structs in Rust code.

Added

• Support for no-std builds, via two new (default-enabled) feature flags:
  • alloc enables the pasta_curves::arithmetic::{CurveAffine, CurveExt} traits, as well as implementations of traits like group::WnafGroup.
  • sqrt-table depends on alloc, and enables the large precomputed tables (stored on the heap) that speed up square root computation.
• pasta_curves::arithmetic::SqrtRatio trait, extending ff::PrimeField with square roots of ratios. This trait is likely to be moved into the ff crate in a future release (once we're satisfied with it).

Removed

• pasta_curves::arithmetic:
  • Field re-export (pasta_curves::group::ff::Field is equivalent).
  • FieldExt::ROOT_OF_UNITY (use ff::PrimeField::root_of_unity instead).
  • FieldExt::{T_MINUS1_OVER2, pow_by_t_minus1_over2, get_lower_32, sqrt_alt, sqrt_ratio} (moved to SqrtRatio trait).
  • FieldExt::{RESCUE_ALPHA, RESCUE_INVALPHA}
  • FieldExt::from_u64 (use From<u64> for ff::PrimeField instead).
  • FieldExt::{from_bytes, read, to_bytes, write} (use ff::PrimeField::{from_repr, to_repr} instead).
  • FieldExt::rand (use ff::Field::random instead).
  • CurveAffine::{read, write} (use group::GroupEncoding::{from_bytes, to_bytes} instead).

Changed

• The crate is now licensed as MIT OR Apache-2.0.

Changed

• Migrated to ff 0.11, group 0.11.

Added

• Implementation of group::WnafGroup for Pallas and Vesta, enabling them to be used with group::Wnaf for targeted performance improvements.

Added

• Implementations of group::cofactor::{CofactorCurve, CofactorCurveAffine} for Pallas and Vesta, enabling them to be used in cofactor-aware protocols that also want to leverage the affine point representation.

Initial release!