lotus/lib/crypto/crypto.go

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package crypto
import (
"bytes"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"io"
secp256k1 "github.com/ipsn/go-secp256k1"
)
// PrivateKeyBytes is the size of a serialized private key.
const PrivateKeyBytes = 32
// PublicKeyBytes is the size of a serialized public key.
const PublicKeyBytes = 65
// PublicKey returns the public key for this private key.
func PublicKey(sk []byte) []byte {
x, y := secp256k1.S256().ScalarBaseMult(sk)
return elliptic.Marshal(secp256k1.S256(), x, y)
}
// Sign signs the given message, which must be 32 bytes long.
func Sign(sk, msg []byte) ([]byte, error) {
return secp256k1.Sign(msg, sk)
}
// Equals compares two private key for equality and returns true if they are the same.
func Equals(sk, other []byte) bool {
return bytes.Equal(sk, other)
}
// Verify checks the given signature and returns true if it is valid.
func Verify(pk, msg, signature []byte) bool {
if len(signature) == 65 {
// Drop the V (1byte) in [R | S | V] style signatures.
// The V (1byte) is the recovery bit and is not apart of the signature verification.
return secp256k1.VerifySignature(pk[:], msg, signature[:len(signature)-1])
}
return secp256k1.VerifySignature(pk[:], msg, signature)
}
// GenerateKeyFromSeed generates a new key from the given reader.
func GenerateKeyFromSeed(seed io.Reader) ([]byte, error) {
key, err := ecdsa.GenerateKey(secp256k1.S256(), seed)
if err != nil {
return nil, err
}
privkey := make([]byte, PrivateKeyBytes)
blob := key.D.Bytes()
// the length is guaranteed to be fixed, given the serialization rules for secp2561k curve points.
copy(privkey[PrivateKeyBytes-len(blob):], blob)
return privkey, nil
}
// GenerateKey creates a new key using secure randomness from crypto.rand.
func GenerateKey() ([]byte, error) {
return GenerateKeyFromSeed(rand.Reader)
}
// EcRecover recovers the public key from a message, signature pair.
func EcRecover(msg, signature []byte) ([]byte, error) {
return secp256k1.RecoverPubkey(msg, signature)
}