6a47700b1d
The `FieldExt` trait was originally the only trait implemented in this
crate. When we added `ff` support, we reworked `FieldExt` to be an
extension trait on top of `ff::PrimeField`, but left the existing impls
in `FieldExt`. This resulted in some circular dependencies that prevent
us from making `FieldExt` conditional (e.g. for no-std support).
This commit removes the cycles like so:
- `ff::PrimeField::{from_repr, to_repr}` were implemented as calls to
`FieldExt::{from_bytes, to_bytes}`. The field encoding/decoding logic
is moved into the `ff::PrimeField` trait impl, and `FieldExt` now
calls into `ff::PrimeField`.
- `ff::Field::sqrt` was implemented in terms of `FieldExt::sqrt_alt`.
Given that the latter is a trivial wrapper around the `SqrtTables`
implementation, we duplicate the call to eliminate the cycle.
- `ff::Field::random` used `FieldExt::from_bytes_wide`, which wraps
either `Fp::from_u512` or `Fq::from_u512`. We now use these internal
methods directly.
|
||
|---|---|---|
| .github | ||
| benches | ||
| book | ||
| src | ||
| .gitignore | ||
| Cargo.toml | ||
| CHANGELOG.md | ||
| katex-header.html | ||
| LICENSE-APACHE | ||
| LICENSE-MIT | ||
| README.md | ||
| rust-toolchain | ||
pasta_curves
This crate provides an implementation of the Pasta elliptic curve constructions, Pallas and Vesta. More details about the Pasta curves can be found in this blog post.
Documentation
Minimum Supported Rust Version
Requires Rust 1.51 or higher.
Minimum supported Rust version can be changed in the future, but it will be done with a minor version bump.
Curve Descriptions
-
Pallas: y2 = x3 + 5 over
GF(0x40000000000000000000000000000000224698fc094cf91b992d30ed00000001). -
Vesta: y2 = x3 + 5 over
GF(0x40000000000000000000000000000000224698fc0994a8dd8c46eb2100000001).
The Pasta curves form a cycle with one another: the order of each curve is exactly the base field of the other. This property is critical to the efficiency of recursive proof systems. They are designed to be highly 2-adic, meaning that a large power-of-two multiplicative subgroup exists in each field. This is important for the performance of polynomial arithmetic over their scalar fields and is essential for protocols similar to PLONK.
These curves can be reproducibly obtained using a curve search utility we’ve published.
License
Licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.