p2p/enr: use compact signature encoding

This commit is contained in:
Felix Lange 2017-12-05 11:47:22 +01:00
parent e490233414
commit 12ac6cd58b
2 changed files with 37 additions and 33 deletions

View file

@ -22,19 +22,18 @@ import (
"crypto/ecdsa"
"errors"
"io"
"math/big"
"sort"
"github.com/btcsuite/btcd/btcec"
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/rlp"
"github.com/btcsuite/btcd/btcec"
)
var ()
// The maximum encoded size of a node record is 300 bytes. Implementations should reject records larger than this size.
const (
ID_SECP256k1_KECCAK = "secp256k1-keccak" // "secp256k1-keccak" identity scheme identifier
var (
errNoID = errors.New("unknown or unspecified identity scheme")
errInvalidSigsize = errors.New("invalid signature size")
)
// Key is implemented by known node record key types.
@ -249,14 +248,11 @@ func (r *Record) signAndEncode(privkey *ecdsa.PrivateKey) error {
return err
}
digest := crypto.Keccak256Hash(sigcontent)
key := btcec.PrivateKey(*privkey)
signature, err := key.Sign(digest.Bytes())
sig, err := (*btcec.PrivateKey)(privkey).Sign(crypto.Keccak256(sigcontent))
if err != nil {
return err
}
r.signature = signature.Serialize()
r.signature = encodeCompactSignature(sig)
blob, err := rlp.EncodeToBytes(r.signature)
if err != nil {
@ -271,35 +267,41 @@ func (r *Record) signAndEncode(privkey *ecdsa.PrivateKey) error {
return nil
}
func (r Record) verifySignature(sigcontent []byte) error {
func (r *Record) verifySignature(sigcontent []byte) error {
// Get identity scheme, public key.
var id ID
_, err := r.Load(&id)
if err != nil {
return err
}
// currently "secp256k1-keccak" is the only known identity scheme
if id != ID_SECP256k1_KECCAK {
return errors.New("unknown identity scheme")
}
// get publickey from record
var secp256k1 Secp256k1
_, err = r.Load(&secp256k1)
if err != nil {
if _, err := r.Load(&id); err != nil {
return err
}
if id != ID_SECP256k1_KECCAK {
return errNoID
}
if _, err := r.Load(&secp256k1); err != nil {
return err
}
digest := crypto.Keccak256Hash(sigcontent)
sign, err := btcec.ParseSignature(r.signature, btcec.S256())
// Verify the signature.
sig, err := parseCompactSignature(r.signature)
if err != nil {
return err
}
if !sign.Verify(digest.Bytes(), (*btcec.PublicKey)(&secp256k1)) {
if !sig.Verify(crypto.Keccak256(sigcontent), (*btcec.PublicKey)(&secp256k1)) {
return errors.New("signature is not valid")
}
return nil
}
func encodeCompactSignature(sig *btcec.Signature) []byte {
b := make([]byte, 64)
math.ReadBits(sig.R, b[:32])
math.ReadBits(sig.S, b[32:])
return b
}
func parseCompactSignature(sig []byte) (*btcec.Signature, error) {
if len(sig) != 64 {
return nil, errInvalidSigsize
}
return &btcec.Signature{R: new(big.Int).SetBytes(sig[:32]), S: new(big.Int).SetBytes(sig[32:])}, nil
}

View file

@ -33,7 +33,9 @@ func (DiscPort) ENRKey() string {
return "discv5"
}
// ID is the name of identity scheme, e.g. "secp256k1-keccak".
const ID_SECP256k1_KECCAK = "secp256k1-keccak" // identity scheme identifier
// ID is the name of the identity scheme, e.g. "secp256k1-keccak".
type ID string
func (ID) ENRKey() string {