ceremonyclient/go-libp2p/core/crypto/ed25519.go

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2023-08-21 03:50:38 +00:00
package crypto
import (
"bytes"
"crypto/ed25519"
"crypto/subtle"
"errors"
"fmt"
"io"
pb "github.com/libp2p/go-libp2p/core/crypto/pb"
"github.com/libp2p/go-libp2p/core/internal/catch"
)
// Ed25519PrivateKey is an ed25519 private key.
type Ed25519PrivateKey struct {
k ed25519.PrivateKey
}
// Ed25519PublicKey is an ed25519 public key.
type Ed25519PublicKey struct {
k ed25519.PublicKey
}
// GenerateEd25519Key generates a new ed25519 private and public key pair.
func GenerateEd25519Key(src io.Reader) (PrivKey, PubKey, error) {
pub, priv, err := ed25519.GenerateKey(src)
if err != nil {
return nil, nil, err
}
return &Ed25519PrivateKey{
k: priv,
},
&Ed25519PublicKey{
k: pub,
},
nil
}
// Type of the private key (Ed25519).
func (k *Ed25519PrivateKey) Type() pb.KeyType {
return pb.KeyType_Ed25519
}
// Raw private key bytes.
func (k *Ed25519PrivateKey) Raw() ([]byte, error) {
// The Ed25519 private key contains two 32-bytes curve points, the private
// key and the public key.
// It makes it more efficient to get the public key without re-computing an
// elliptic curve multiplication.
buf := make([]byte, len(k.k))
copy(buf, k.k)
return buf, nil
}
func (k *Ed25519PrivateKey) pubKeyBytes() []byte {
return k.k[ed25519.PrivateKeySize-ed25519.PublicKeySize:]
}
// Equals compares two ed25519 private keys.
func (k *Ed25519PrivateKey) Equals(o Key) bool {
edk, ok := o.(*Ed25519PrivateKey)
if !ok {
return basicEquals(k, o)
}
return subtle.ConstantTimeCompare(k.k, edk.k) == 1
}
// GetPublic returns an ed25519 public key from a private key.
func (k *Ed25519PrivateKey) GetPublic() PubKey {
return &Ed25519PublicKey{k: k.pubKeyBytes()}
}
// Sign returns a signature from an input message.
func (k *Ed25519PrivateKey) Sign(msg []byte) (res []byte, err error) {
defer func() { catch.HandlePanic(recover(), &err, "ed15519 signing") }()
return ed25519.Sign(k.k, msg), nil
}
// Type of the public key (Ed25519).
func (k *Ed25519PublicKey) Type() pb.KeyType {
return pb.KeyType_Ed25519
}
// Raw public key bytes.
func (k *Ed25519PublicKey) Raw() ([]byte, error) {
return k.k, nil
}
// Equals compares two ed25519 public keys.
func (k *Ed25519PublicKey) Equals(o Key) bool {
edk, ok := o.(*Ed25519PublicKey)
if !ok {
return basicEquals(k, o)
}
return bytes.Equal(k.k, edk.k)
}
// Verify checks a signature against the input data.
func (k *Ed25519PublicKey) Verify(data []byte, sig []byte) (success bool, err error) {
defer func() {
catch.HandlePanic(recover(), &err, "ed15519 signature verification")
// To be safe.
if err != nil {
success = false
}
}()
return ed25519.Verify(k.k, data, sig), nil
}
// UnmarshalEd25519PublicKey returns a public key from input bytes.
func UnmarshalEd25519PublicKey(data []byte) (PubKey, error) {
if len(data) != 32 {
return nil, errors.New("expect ed25519 public key data size to be 32")
}
return &Ed25519PublicKey{
k: ed25519.PublicKey(data),
}, nil
}
// UnmarshalEd25519PrivateKey returns a private key from input bytes.
func UnmarshalEd25519PrivateKey(data []byte) (PrivKey, error) {
switch len(data) {
case ed25519.PrivateKeySize + ed25519.PublicKeySize:
// Remove the redundant public key. See issue #36.
redundantPk := data[ed25519.PrivateKeySize:]
pk := data[ed25519.PrivateKeySize-ed25519.PublicKeySize : ed25519.PrivateKeySize]
if subtle.ConstantTimeCompare(pk, redundantPk) == 0 {
return nil, errors.New("expected redundant ed25519 public key to be redundant")
}
// No point in storing the extra data.
newKey := make([]byte, ed25519.PrivateKeySize)
copy(newKey, data[:ed25519.PrivateKeySize])
data = newKey
case ed25519.PrivateKeySize:
default:
return nil, fmt.Errorf(
"expected ed25519 data size to be %d or %d, got %d",
ed25519.PrivateKeySize,
ed25519.PrivateKeySize+ed25519.PublicKeySize,
len(data),
)
}
return &Ed25519PrivateKey{
k: ed25519.PrivateKey(data),
}, nil
}