lbcd/btcec/privkey.go

72 lines
2.2 KiB
Go

// Copyright (c) 2013-2014 Conformal Systems LLC.
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package btcec
import (
"crypto/ecdsa"
"crypto/rand"
"math/big"
)
// PrivateKey wraps an ecdsa.PrivateKey as a convenience mainly for signing
// things with the the private key without having to directly import the ecdsa
// package.
type PrivateKey ecdsa.PrivateKey
// PrivKeyFromBytes returns a private and public key for `curve' based on the
// private key passed as an argument as a byte slice.
func PrivKeyFromBytes(curve *KoblitzCurve, pk []byte) (*PrivateKey,
*PublicKey) {
x, y := curve.ScalarBaseMult(pk)
priv := &ecdsa.PrivateKey{
PublicKey: ecdsa.PublicKey{
Curve: curve,
X: x,
Y: y,
},
D: new(big.Int).SetBytes(pk),
}
return (*PrivateKey)(priv), (*PublicKey)(&priv.PublicKey)
}
// NewPrivateKey is a wrapper for ecdsa.GenerateKey that returns a PrivateKey
// instead of the normal ecdsa.PrivateKey.
func NewPrivateKey(curve *KoblitzCurve) (*PrivateKey, error) {
key, err := ecdsa.GenerateKey(curve, rand.Reader)
if err != nil {
return nil, err
}
return (*PrivateKey)(key), nil
}
// PubKey returns the PublicKey corresponding to this private key.
func (p *PrivateKey) PubKey() *PublicKey {
return (*PublicKey)(&p.PublicKey)
}
// ToECDSA returns the private key as a *ecdsa.PrivateKey.
func (p *PrivateKey) ToECDSA() *ecdsa.PrivateKey {
return (*ecdsa.PrivateKey)(p)
}
// Sign generates an ECDSA signature for the provided hash (which should be the result
// of hashing a larger message) using the private key. Produced signature
// is deterministic (same message and same key yield the same signature) and canonical
// in accordance with RFC6979 and BIP0062.
func (p *PrivateKey) Sign(hash []byte) (*Signature, error) {
return signRFC6979(p, hash)
}
// PrivKeyBytesLen defines the length in bytes of a serialized private key.
const PrivKeyBytesLen = 32
// Serialize returns the private key number d as a big-endian binary-encoded
// number, padded to a length of 32 bytes.
func (p *PrivateKey) Serialize() []byte {
b := make([]byte, 0, PrivKeyBytesLen)
return paddedAppend(PrivKeyBytesLen, b, p.ToECDSA().D.Bytes())
}