lbcd/privkey.go

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// 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 is an ecdsa.PrivateKey
// It provides a method Sign
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)
}
// ToECDSA returns the private key as a *ecdsa.PrivateKey.
func (p *PrivateKey) ToECDSA() *ecdsa.PrivateKey {
return (*ecdsa.PrivateKey)(p)
}
// Sign wraps ecdsa.Sign to sign an arbitrary length hash (which should be the result of hashing a larger message) using the private key.
// It returns the signature as a *Signature. The security of the private key depends on the entropy of rand (crypto/rand.Reader).
func (p *PrivateKey) Sign(hash []byte) (*Signature, error) {
r, s, err := ecdsa.Sign(rand.Reader, p.ToECDSA(), hash)
if err != nil {
return nil, err
}
sig := &Signature{
R: r,
S: s,
}
return sig, nil
}