77c02f36ee
- Keep comments to 80 cols for consistency with the rest of the code base - Made verify a method off of Signature instead of PublicKey since one verifies a signature with a public key as opposed to the other way around - Return new signature from Sign function directly rather than creating a local temporary variable - Modify a couple of comments as recommended by @owainga - Update sample usage in doc.go for both signing messages and verifying signatures ok @owainga
102 lines
2.8 KiB
Go
102 lines
2.8 KiB
Go
// Copyright (c) 2013-2014 Conformal Systems LLC.
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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/*
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Package btcec implements support for the elliptic curves needed for bitcoin.
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Bitcoin uses elliptic curve cryptography using koblitz curves
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(specifically secp256k1) for cryptographic functions. See
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http://www.secg.org/collateral/sec2_final.pdf for details on the
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standard.
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This package provides the data structures and functions implementing the
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crypto/elliptic Curve interface in order to permit using these curves
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with the standard crypto/ecdsa package provided with go. Helper
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functionality is provided to parse signatures and public keys from
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standard formats. It was designed for use with btcd, but should be
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general enough for other uses of elliptic curve crypto. It was based on
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some initial work by ThePiachu.
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Usage
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To verify a secp256k1 signature, the following may be done:
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package main
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import (
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"encoding/hex"
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"github.com/conformal/btcec"
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"github.com/conformal/btcwire"
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"log"
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)
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func main() {
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// Decode hex-encoded serialized public key.
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pubKeyBytes, err := hex.DecodeString("02a673638cb9587cb68ea08dbef685c"+
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"6f2d2a751a8b3c6f2a7e9a4999e6e4bfaf5")
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if err != nil {
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log.Fatal(err)
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}
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pubKey, err := btcec.ParsePubKey(pubKeyBytes, btcec.S256())
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if err != nil {
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log.Fatal(err)
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}
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// Decode hex-encoded serialized signature.
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sigBytes, err := hex.DecodeString("30450220090ebfb3690a0ff115bb1b38b"+
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"8b323a667b7653454f1bccb06d4bbdca42c2079022100ec95778b51e707"+
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"1cb1205f8bde9af6592fc978b0452dafe599481c46d6b2e479")
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if err != nil {
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log.Fatal(err)
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}
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decodedSig, err := btcec.ParseSignature(sigBytes, btcec.S256())
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if err != nil {
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log.Fatal(err)
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}
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// Verify the signature for the message using the public key.
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message := "test message"
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messageHash := btcwire.DoubleSha256([]byte(message))
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if decodedSig.Verify(messageHash, pubKey) {
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log.Println("Signature Verified")
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}
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}
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To sign a message using a secp256k1 private key, the following may be done:
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package main
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import (
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"encoding/hex"
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"github.com/conformal/btcec"
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"github.com/conformal/btcwire"
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"log"
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)
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func main() {
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// Decode a hex-encoded private key.
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pkBytes, err := hex.DecodeString("22a47fa09a223f2aa079edf85a7c2d4f87"+
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"20ee63e502ee2869afab7de234b80c")
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if err != nil {
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log.Fatal(err)
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}
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priv, pub := btcec.PrivKeyFromBytes(btcec.S256(), pkBytes)
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// Sign a message using the private key.
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message := "test message"
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messageHash := btcwire.DoubleSha256([]byte(message))
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sig, err := priv.Sign(messageHash)
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if err != nil {
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log.Fatal(err)
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}
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log.Printf("Serialized Signature: %x\n", sig.Serialize())
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// Verify the signature for the message using the public key.
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if sig.Verify(messageHash, pub) {
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log.Println("Signature Verified")
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}
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}
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*/
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package btcec
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