[![Build Status](https://travis-ci.org/rust-bitcoin/rust-secp256k1.png?branch=master)](https://travis-ci.org/rust-bitcoin/rust-secp256k1)

[Full documentation](https://docs.rs/secp256k1/)

### rust-secp256k1

`rust-secp256k1` is a wrapper around [libsecp256k1](https://github.com/bitcoin-core/secp256k1),
a C library by Pieter Wuille for producing ECDSA signatures using the SECG curve
`secp256k1`. This library
* exposes type-safe Rust bindings for all `libsecp256k1` functions
* implements key generation
* implements deterministic nonce generation via RFC6979
* implements many unit tests, adding to those already present in `libsecp256k1`
* makes no allocations (except in unit tests) for efficiency and use in freestanding implementations

### Contributing

Contributions to this library are welcome. A few guidelines:

* Any breaking changes must have an accompanied entry in CHANGELOG.md
* No new dependencies, please.
* No crypto should be implemented in Rust, with the possible exception of hash functions. Cryptographic contributions should be directed upstream to libsecp256k1.
* This library should always compile with any combination of features on **Rust 1.29**.

## A note on Rust 1.29 support

The build dependency `cc` might require a more recent version of the Rust compiler.
To ensure compilation with Rust 1.29.0, pin its version in your `Cargo.lock`
with `cargo update -p cc --precise 1.0.41`. If you're using `secp256k1` in a library,
to make sure it compiles in CI, you'll need to generate a lockfile first.
Example for Travis CI:
```yml
before_script:
  - if [ "$TRAVIS_RUST_VERSION" == "1.29.0" ]; then
    cargo generate-lockfile --verbose && cargo update -p cc --precise "1.0.41" --verbose;
    fi
```

## Fuzzing

If you want to fuzz this library, or any library which depends on it, you will
probably want to disable the actual cryptography, since fuzzers are unable to
forge signatures and therefore won't test many interesting codepaths. To instead
use a trivially-broken but fuzzer-accessible signature scheme, compile with
`--cfg=fuzzing` in your `RUSTFLAGS` variable.

Note that `cargo hfuzz` sets this config flag automatically.