9be5c5cbd9
This commit essentially rewrites all of the primitives needed to perform the arithmetic for ECDSA signature verification of secp256k1 signatures to significantly speed it up. Benchmarking has shown signature verification is roughly 10 times faster with this commit over the previous. In particular, it introduces a new field value which is used to perform the modular field arithmetic using fixed-precision operations specifically tailored for the secp256k1 prime. The field also takes advantage of special properties of the prime for significantly faster modular reduction than is available through generic methods. In addition, the curve point addition and doubling have been optimized minimize the number of field multiplications in favor field squarings since they are quite a bit faster. They routines also now look for certain assumptions such as z values of 1 or equivalent z values which can be used to further reduce the number of multiplicaitons needed when possible. Note there are still quite a few more optimizations that could be done such as using precomputation for ScalarBaseMult, making use of the secp256k1 endomorphism, and using windowed NAF, however this work already offers significant performance improvements. For example, testing 10000 random signature verifications resulted in: New btcec took 15.9821565s Old btcec took 2m34.1016716s Closes conformal/btcd#26. |
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|---|---|---|
| .gitignore | ||
| btcec.go | ||
| btcec_test.go | ||
| cov_report.sh | ||
| doc.go | ||
| field.go | ||
| internal_test.go | ||
| LICENSE | ||
| pubkey.go | ||
| pubkey_test.go | ||
| README.md | ||
| signature.go | ||
| signature_test.go | ||
| test_coverage.txt | ||
btcec
Package btcec implements elliptic curve cryptography using koblitz curves
(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 is aiming to reach 100% code 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
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.
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
$ go get github.com/conformal/btcec
TODO
- Increase test coverage to 100%
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:
gpg --import GIT-GPG-KEY-conformal.txt -
Verify the release tag with the following command where
TAG_NAMEis a placeholder for the specific tag: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.