keychain: add single key wrapper implementations

This commit is contained in:
Oliver Gugger 2020-04-28 10:06:20 +02:00
parent 6cf1844b0e
commit cf0380ac81
No known key found for this signature in database
GPG Key ID: 8E4256593F177720
2 changed files with 138 additions and 0 deletions

82
keychain/ecdh.go Normal file
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package keychain
import (
"crypto/sha256"
"github.com/btcsuite/btcd/btcec"
)
// NewPubKeyECDH wraps the given key of the key ring so it adheres to the
// SingleKeyECDH interface.
func NewPubKeyECDH(keyDesc KeyDescriptor, ecdh ECDHRing) *PubKeyECDH {
return &PubKeyECDH{
keyDesc: keyDesc,
ecdh: ecdh,
}
}
// PubKeyECDH is an implementation of the SingleKeyECDH interface. It wraps an
// ECDH key ring so it can perform ECDH shared key generation against a single
// abstracted away private key.
type PubKeyECDH struct {
keyDesc KeyDescriptor
ecdh ECDHRing
}
// PubKey returns the public key of the private key that is abstracted away by
// the interface.
//
// NOTE: This is part of the SingleKeyECDH interface.
func (p *PubKeyECDH) PubKey() *btcec.PublicKey {
return p.keyDesc.PubKey
}
// ECDH performs a scalar multiplication (ECDH-like operation) between the
// abstracted private key and a remote public key. The output returned will be
// the sha256 of the resulting shared point serialized in compressed format. If
// k is our private key, and P is the public key, we perform the following
// operation:
//
// sx := k*P
// s := sha256(sx.SerializeCompressed())
//
// NOTE: This is part of the SingleKeyECDH interface.
func (p *PubKeyECDH) ECDH(pubKey *btcec.PublicKey) ([32]byte, error) {
return p.ecdh.ECDH(p.keyDesc, pubKey)
}
// PrivKeyECDH is an implementation of the SingleKeyECDH in which we do have the
// full private key. This can be used to wrap a temporary key to conform to the
// SingleKeyECDH interface.
type PrivKeyECDH struct {
// PrivKey is the private key that is used for the ECDH operation.
PrivKey *btcec.PrivateKey
}
// PubKey returns the public key of the private key that is abstracted away by
// the interface.
//
// NOTE: This is part of the SingleKeyECDH interface.
func (p *PrivKeyECDH) PubKey() *btcec.PublicKey {
return p.PrivKey.PubKey()
}
// ECDH performs a scalar multiplication (ECDH-like operation) between the
// abstracted private key and a remote public key. The output returned will be
// the sha256 of the resulting shared point serialized in compressed format. If
// k is our private key, and P is the public key, we perform the following
// operation:
//
// sx := k*P
// s := sha256(sx.SerializeCompressed())
//
// NOTE: This is part of the SingleKeyECDH interface.
func (p *PrivKeyECDH) ECDH(pub *btcec.PublicKey) ([32]byte, error) {
s := &btcec.PublicKey{}
s.X, s.Y = btcec.S256().ScalarMult(pub.X, pub.Y, p.PrivKey.D.Bytes())
return sha256.Sum256(s.SerializeCompressed()), nil
}
var _ SingleKeyECDH = (*PubKeyECDH)(nil)
var _ SingleKeyECDH = (*PrivKeyECDH)(nil)

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keychain/signer.go Normal file
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package keychain
import "github.com/btcsuite/btcd/btcec"
func NewPubKeyDigestSigner(keyDesc KeyDescriptor,
signer DigestSignerRing) *PubKeyDigestSigner {
return &PubKeyDigestSigner{
keyDesc: keyDesc,
digestSigner: signer,
}
}
type PubKeyDigestSigner struct {
keyDesc KeyDescriptor
digestSigner DigestSignerRing
}
func (p *PubKeyDigestSigner) PubKey() *btcec.PublicKey {
return p.keyDesc.PubKey
}
func (p *PubKeyDigestSigner) SignDigest(digest [32]byte) (*btcec.Signature,
error) {
return p.digestSigner.SignDigest(p.keyDesc, digest)
}
func (p *PubKeyDigestSigner) SignDigestCompact(digest [32]byte) ([]byte,
error) {
return p.digestSigner.SignDigestCompact(p.keyDesc, digest)
}
type PrivKeyDigestSigner struct {
PrivKey *btcec.PrivateKey
}
func (p *PrivKeyDigestSigner) PubKey() *btcec.PublicKey {
return p.PrivKey.PubKey()
}
func (p *PrivKeyDigestSigner) SignDigest(digest [32]byte) (*btcec.Signature,
error) {
return p.PrivKey.Sign(digest[:])
}
func (p *PrivKeyDigestSigner) SignDigestCompact(digest [32]byte) ([]byte,
error) {
return btcec.SignCompact(btcec.S256(), p.PrivKey, digest[:], true)
}
var _ SingleKeyDigestSigner = (*PubKeyDigestSigner)(nil)
var _ SingleKeyDigestSigner = (*PrivKeyDigestSigner)(nil)