btcec
=====

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

Package btcec implements elliptic curve cryptography needed for working with
Bitcoin (secp256k1 only for now). It is designed so that it may be used with the
standard crypto/ecdsa packages provided with go.  There is a test suite which
provides extensive coverage.  See `test_coverage.txt` for the current coverage
(using gocov).  On a UNIX-like OS, the script `cov_report.sh` can be used to
generate the report.  Package btcec uses work from ThePiachu which is licensed
under the same terms as Go.  The Conformal original is licensed under the
liberal ISC license.

This package is one of the core packages from btcd, an alternative full-node
implementation of bitcoin which is under active development by Conformal.
Although it was primarily written for btcd, this package has intentionally been
designed so it can be used as a standalone package for any projects needing to
use secp256k1 elliptic curve cryptography.

## Sample Use

```Go
	import crypto/ecdsa

	pubKey, err := btcec.ParsePubKey(pkStr, btcec.S256())

	signature, err := btcec.ParseSignature(sigStr, btcec.S256())

	ok := ecdsa.Verify(pubKey, message, signature.R, signature.S)
```

## Documentation

Full `go doc` style documentation for the project can be viewed online without
installing this package by using the GoDoc site
[here](http://godoc.org/github.com/conformal/btcec).

You can also view the documentation locally once the package is installed with
the `godoc` tool by running `godoc -http=":6060"` and pointing your browser to
http://localhost:6060/pkg/github.com/conformal/btcec

## Installation

```bash
$ go get github.com/conformal/btcec
```

## GPG Verification Key

All official release tags are signed by Conformal so users can ensure the code
has not been tampered with and is coming from Conformal.  To verify the
signature perform the following:

- Download the public key from the Conformal website at
  https://opensource.conformal.com/GIT-GPG-KEY-conformal.txt

- Import the public key into your GPG keyring:
  ```bash
  gpg --import GIT-GPG-KEY-conformal.txt
  ```

- Verify the release tag with the following command where `TAG_NAME` is a
  placeholder for the specific tag:
  ```bash
  git tag -v TAG_NAME
  ```

## License

Package btcec is licensed under the liberal ISC License except for
btcec.go and btcec_test.go which is under the same license as Go.