diff options
Diffstat (limited to 'p2p/crypto.go')
| -rw-r--r-- | p2p/crypto.go | 111 |
1 files changed, 61 insertions, 50 deletions
diff --git a/p2p/crypto.go b/p2p/crypto.go index b6d600826..dbef022cc 100644 --- a/p2p/crypto.go +++ b/p2p/crypto.go @@ -12,11 +12,12 @@ import ( ) var ( - sskLen int = 16 // ecies.MaxSharedKeyLength(pubKey) / 2 - sigLen int = 65 // elliptic S256 - keyLen int = 32 // ECDSA - msgLen int = sigLen + 3*keyLen + 1 // 162 - resLen int = 65 // + sskLen int = 16 // ecies.MaxSharedKeyLength(pubKey) / 2 + sigLen int = 65 // elliptic S256 + pubLen int = 64 // 512 bit pubkey in uncompressed representation without format byte + keyLen int = 32 // ECDSA + msgLen int = 194 // sigLen + keyLen + pubLen + keyLen + 1 = 194 + resLen int = 97 // pubLen + keyLen + 1 ) // aesSecret, macSecret, egressMac, ingress @@ -25,20 +26,21 @@ type secretRW struct { } type cryptoId struct { - prvKey *ecdsa.PrivateKey - pubKey *ecdsa.PublicKey - pubKeyDER []byte + prvKey *ecdsa.PrivateKey + pubKey *ecdsa.PublicKey + pubKeyS []byte } func newCryptoId(id ClientIdentity) (self *cryptoId, err error) { // will be at server init - var prvKeyDER []byte = id.PrivKey() - if prvKeyDER == nil { + var prvKeyS []byte = id.PrivKey() + if prvKeyS == nil { err = fmt.Errorf("no private key for client") return } - // initialise ecies private key via importing DER encoded keys (known via our own clientIdentity) - var prvKey = crypto.ToECDSA(prvKeyDER) + // initialise ecies private key via importing keys (known via our own clientIdentity) + // the key format is what elliptic package is using: elliptic.Marshal(Curve, X, Y) + var prvKey = crypto.ToECDSA(prvKeyS) if prvKey == nil { err = fmt.Errorf("invalid private key for client") return @@ -50,16 +52,16 @@ func newCryptoId(id ClientIdentity) (self *cryptoId, err error) { // to be created at server init shared between peers and sessions // for reuse, call wth ReadAt, no reset seek needed } - self.pubKeyDER = id.Pubkey() + self.pubKeyS = id.Pubkey() return } -func (self *cryptoId) Run(conn io.ReadWriter, remotePubKeyDER []byte, sessionToken []byte, initiator bool) (token []byte, rw *secretRW, err error) { +func (self *cryptoId) Run(conn io.ReadWriter, remotePubKeyS []byte, sessionToken []byte, initiator bool) (token []byte, rw *secretRW, err error) { var auth, initNonce, recNonce []byte var randomPrivKey *ecdsa.PrivateKey var remoteRandomPubKey *ecdsa.PublicKey if initiator { - if auth, initNonce, randomPrivKey, _, err = self.startHandshake(remotePubKeyDER, sessionToken); err != nil { + if auth, initNonce, randomPrivKey, _, err = self.startHandshake(remotePubKeyS, sessionToken); err != nil { return } conn.Write(auth) @@ -76,10 +78,9 @@ func (self *cryptoId) Run(conn io.ReadWriter, remotePubKeyDER []byte, sessionTok // Extract info from the authentication. The initiator starts by sending us a handshake that we need to respond to. // so we read auth message first, then respond var response []byte - if response, recNonce, initNonce, randomPrivKey, err = self.respondToHandshake(auth, remotePubKeyDER, sessionToken); err != nil { + if response, recNonce, initNonce, randomPrivKey, remoteRandomPubKey, err = self.respondToHandshake(auth, remotePubKeyS, sessionToken); err != nil { return } - remoteRandomPubKey = &randomPrivKey.PublicKey conn.Write(response) } return self.newSession(initNonce, recNonce, auth, randomPrivKey, remoteRandomPubKey) @@ -100,11 +101,29 @@ The handshake is the process by which the peers establish their connection for a */ -func (self *cryptoId) startHandshake(remotePubKeyDER, sessionToken []byte) (auth []byte, initNonce []byte, randomPrvKey *ecdsa.PrivateKey, remotePubKey *ecdsa.PublicKey, err error) { +func ImportPublicKey(pubKey []byte) (pubKeyEC *ecdsa.PublicKey, err error) { + var pubKey65 []byte + switch len(pubKey) { + case 64: + pubKey65 = append([]byte{0x04}, pubKey...) + case 65: + pubKey65 = pubKey + default: + return nil, fmt.Errorf("invalid public key length %v (expect 64/65)", len(pubKey)) + } + return crypto.ToECDSAPub(pubKey65), nil +} + +func ExportPublicKey(pubKeyEC *ecdsa.PublicKey) (pubKey []byte, err error) { + if pubKeyEC == nil { + return nil, fmt.Errorf("no ECDSA public key given") + } + return crypto.FromECDSAPub(pubKeyEC)[1:], nil +} + +func (self *cryptoId) startHandshake(remotePubKeyS, sessionToken []byte) (auth []byte, initNonce []byte, randomPrvKey *ecdsa.PrivateKey, remotePubKey *ecdsa.PublicKey, err error) { // session init, common to both parties - remotePubKey = crypto.ToECDSAPub(remotePubKeyDER) - if remotePubKey == nil { - err = fmt.Errorf("invalid remote public key") + if remotePubKey, err = ImportPublicKey(remotePubKeyS); err != nil { return } @@ -116,8 +135,6 @@ func (self *cryptoId) startHandshake(remotePubKeyDER, sessionToken []byte) (auth if sessionToken, err = ecies.ImportECDSA(self.prvKey).GenerateShared(ecies.ImportECDSAPublic(remotePubKey), sskLen, sskLen); err != nil { return } - // this will not stay here ;) - fmt.Printf("secret generated: %v %x", len(sessionToken), sessionToken) // tokenFlag = 0x00 // redundant } else { // for known peers, we use stored token from the previous session @@ -128,9 +145,7 @@ func (self *cryptoId) startHandshake(remotePubKeyDER, sessionToken []byte) (auth // E(remote-pubk, S(ecdhe-random, token^nonce) || H(ecdhe-random-pubk) || pubk || nonce || 0x1) // allocate msgLen long message, var msg []byte = make([]byte, msgLen) - // generate sskLen long nonce initNonce = msg[msgLen-keyLen-1 : msgLen-1] - // nonce = msg[msgLen-sskLen-1 : msgLen-1] if _, err = rand.Read(initNonce); err != nil { return } @@ -150,48 +165,45 @@ func (self *cryptoId) startHandshake(remotePubKeyDER, sessionToken []byte) (auth if signature, err = crypto.Sign(sharedSecret, randomPrvKey); err != nil { return } - fmt.Printf("signature generated: %v %x", len(signature), signature) // message // signed-shared-secret || H(ecdhe-random-pubk) || pubk || nonce || 0x0 copy(msg, signature) // copy signed-shared-secret // H(ecdhe-random-pubk) - copy(msg[sigLen:sigLen+keyLen], crypto.Sha3(crypto.FromECDSAPub(&randomPrvKey.PublicKey))) + var randomPubKey64 []byte + if randomPubKey64, err = ExportPublicKey(&randomPrvKey.PublicKey); err != nil { + return + } + copy(msg[sigLen:sigLen+keyLen], crypto.Sha3(randomPubKey64)) // pubkey copied to the correct segment. - copy(msg[sigLen+keyLen:sigLen+2*keyLen], self.pubKeyDER) + copy(msg[sigLen+keyLen:sigLen+keyLen+pubLen], self.pubKeyS) // nonce is already in the slice // stick tokenFlag byte to the end msg[msgLen-1] = tokenFlag - fmt.Printf("plaintext message generated: %v %x", len(msg), msg) - // encrypt using remote-pubk // auth = eciesEncrypt(remote-pubk, msg) if auth, err = crypto.Encrypt(remotePubKey, msg); err != nil { return } - fmt.Printf("encrypted message generated: %v %x\n used pubkey: %x\n", len(auth), auth, crypto.FromECDSAPub(remotePubKey)) return } // verifyAuth is called by peer if it accepted (but not initiated) the connection -func (self *cryptoId) respondToHandshake(auth, remotePubKeyDER, sessionToken []byte) (authResp []byte, respNonce []byte, initNonce []byte, randomPrivKey *ecdsa.PrivateKey, err error) { +func (self *cryptoId) respondToHandshake(auth, remotePubKeyS, sessionToken []byte) (authResp []byte, respNonce []byte, initNonce []byte, randomPrivKey *ecdsa.PrivateKey, remoteRandomPubKey *ecdsa.PublicKey, err error) { var msg []byte - remotePubKey := crypto.ToECDSAPub(remotePubKeyDER) - if remotePubKey == nil { - err = fmt.Errorf("invalid public key") + var remotePubKey *ecdsa.PublicKey + if remotePubKey, err = ImportPublicKey(remotePubKeyS); err != nil { return } - fmt.Printf("encrypted message received: %v %x\n used pubkey: %x\n", len(auth), auth, crypto.FromECDSAPub(self.pubKey)) // they prove that msg is meant for me, // I prove I possess private key if i can read it if msg, err = crypto.Decrypt(self.prvKey, auth); err != nil { return } - fmt.Printf("\nplaintext message retrieved: %v %x\n", len(msg), msg) var tokenFlag byte if sessionToken == nil { @@ -201,7 +213,6 @@ func (self *cryptoId) respondToHandshake(auth, remotePubKeyDER, sessionToken []b if sessionToken, err = ecies.ImportECDSA(self.prvKey).GenerateShared(ecies.ImportECDSAPublic(remotePubKey), sskLen, sskLen); err != nil { return } - fmt.Printf("secret generated: %v %x", len(sessionToken), sessionToken) // tokenFlag = 0x00 // redundant } else { // for known peers, we use stored token from the previous session @@ -214,21 +225,19 @@ func (self *cryptoId) respondToHandshake(auth, remotePubKeyDER, sessionToken []b // they prove they own the private key belonging to ecdhe-random-pubk // we can now reconstruct the signed message and recover the peers pubkey var signedMsg = Xor(sessionToken, initNonce) - var remoteRandomPubKeyDER []byte - if remoteRandomPubKeyDER, err = secp256k1.RecoverPubkey(signedMsg, msg[:sigLen]); err != nil { + var remoteRandomPubKeyS []byte + if remoteRandomPubKeyS, err = secp256k1.RecoverPubkey(signedMsg, msg[:sigLen]); err != nil { return } // convert to ECDSA standard - remoteRandomPubKey := crypto.ToECDSAPub(remoteRandomPubKeyDER) - if remoteRandomPubKey == nil { - err = fmt.Errorf("invalid remote public key") + if remoteRandomPubKey, err = ImportPublicKey(remoteRandomPubKeyS); err != nil { return } // now we find ourselves a long task too, fill it random var resp = make([]byte, resLen) // generate keyLen long nonce - respNonce = msg[resLen-keyLen-1 : msgLen-1] + respNonce = resp[pubLen : pubLen+keyLen] if _, err = rand.Read(respNonce); err != nil { return } @@ -238,7 +247,11 @@ func (self *cryptoId) respondToHandshake(auth, remotePubKeyDER, sessionToken []b } // responder auth message // E(remote-pubk, ecdhe-random-pubk || nonce || 0x0) - copy(resp[:keyLen], crypto.FromECDSAPub(&randomPrivKey.PublicKey)) + var randomPubKeyS []byte + if randomPubKeyS, err = ExportPublicKey(&randomPrivKey.PublicKey); err != nil { + return + } + copy(resp[:pubLen], randomPubKeyS) // nonce is already in the slice resp[resLen-1] = tokenFlag @@ -259,11 +272,9 @@ func (self *cryptoId) completeHandshake(auth []byte) (respNonce []byte, remoteRa return } - respNonce = msg[resLen-keyLen-1 : resLen-1] - var remoteRandomPubKeyDER = msg[:keyLen] - remoteRandomPubKey = crypto.ToECDSAPub(remoteRandomPubKeyDER) - if remoteRandomPubKey == nil { - err = fmt.Errorf("invalid ecdh random remote public key") + respNonce = msg[pubLen : pubLen+keyLen] + var remoteRandomPubKeyS = msg[:pubLen] + if remoteRandomPubKey, err = ImportPublicKey(remoteRandomPubKeyS); err != nil { return } if msg[resLen-1] == 0x01 { |