# [RustCrypto]: secp256k1 elliptic curve

[![crate][crate-image]][crate-link]
[![Docs][docs-image]][docs-link]
[![Build Status][build-image]][build-link]
![Apache2/MIT licensed][license-image]
![Rust Version][rustc-image]
[![Project Chat][chat-image]][chat-link]

[secp256k1] elliptic curve library written in pure Rust with
support for [ECDSA] signing/verification/public-key recovery, Taproot
[Schnorr signatures] as defined in BIP340, Elliptic Curve Diffie-Hellman (ECDH),
and general-purpose secp256k1 elliptic curve group operations which can be used
to implement arbitrary group-based protocols.

Uses traits and base types from the [`elliptic-curve`] crate.

Optionally includes a secp256k1 [`arithmetic`] feature providing scalar and
point types (projective/affine) with support for constant-time scalar
multiplication. Additionally, implements traits from the [`group`] crate
which can be used to generically construct group-based protocols.

[Documentation][docs-link]

## Minimum Supported Rust Version

Rust **1.73** or higher.

Minimum supported Rust version can be changed in the future, but it will be
done with a minor version bump.

## SemVer Policy

- All on-by-default features of this library are covered by SemVer
- MSRV is considered exempt from SemVer as noted above

## License

All crates licensed under either of

 * [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0)
 * [MIT license](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.

[//]: # (badges)

[crate-image]: https://buildstats.info/crate/p256k
[crate-link]: https://crates.io/crates/p256k
[docs-image]: https://docs.rs/p256k/badge.svg
[docs-link]: https://docs.rs/p256k/
[build-image]: https://github.com/RustCrypto/elliptic-curves/workflows/p256k/badge.svg?branch=master&event=push
[build-link]: https://github.com/RustCrypto/elliptic-curves/actions?query=workflow%3Ap256k
[license-image]: https://img.shields.io/badge/license-Apache2.0/MIT-blue.svg
[rustc-image]: https://img.shields.io/badge/rustc-1.73+-blue.svg
[chat-image]: https://img.shields.io/badge/zulip-join_chat-blue.svg
[chat-link]: https://rustcrypto.zulipchat.com/#narrow/stream/260040-elliptic-curves

[//]: # (general links)

[RustCrypto]: https://github.com/RustCrypto/
[secp256k1]: https://en.bitcoin.it/wiki/Secp256k1
[`elliptic-curve`]: https://github.com/RustCrypto/traits/tree/master/elliptic-curve
[`arithmetic`]: https://docs.rs/p256k/latest/p256k/arithmetic/index.html
[`group`]: https://github.com/zkcrypto/group
[ECDH]: https://en.wikipedia.org/wiki/Elliptic-curve_Diffie-Hellman
[ECDSA]: https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm
[Schnorr signatures]: https://en.wikipedia.org/wiki/Schnorr_signature
[audited by NCC Group]: https://research.nccgroup.com/2023/08/30/public-report-entropy-rust-cryptography-review/
[Entropy]: https://entropy.xyz/
[BIP0062]: https://github.com/bitcoin/bips/blob/master/bip-0062.mediawiki
[BIP0340]: https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki