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@ -53,10 +53,24 @@ func newCryptoId(id ClientIdentity) (self *cryptoId, err error) { |
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return |
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} |
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// initAuth is called by peer if it initiated the connection
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func (self *cryptoId) initAuth(remotePubKeyDER, sessionToken []byte) (auth []byte, initNonce []byte, remotePubKey *ecdsa.PublicKey, err error) { |
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/* startHandshake is called by peer if it initiated the connection. |
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By protocol spec, the party who initiates the connection (initiator) will send an 'auth' packet |
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New: authInitiator -> E(remote-pubk, S(ecdhe-random, ecdh-shared-secret^nonce) || H(ecdhe-random-pubk) || pubk || nonce || 0x0) |
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authRecipient -> E(remote-pubk, ecdhe-random-pubk || nonce || 0x0) |
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Known: authInitiator = E(remote-pubk, S(ecdhe-random, token^nonce) || H(ecdhe-random-pubk) || pubk || nonce || 0x1) |
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authRecipient = E(remote-pubk, ecdhe-random-pubk || nonce || 0x1) // token found
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authRecipient = E(remote-pubk, ecdhe-random-pubk || nonce || 0x0) // token not found
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The caller provides the public key of the peer as conjuctured from lookup based on IP:port, given as user input or proven by signatures. The caller must have access to persistant information about the peers, and pass the previous session token as an argument to cryptoId. |
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The handshake is the process by which the peers establish their connection for a session. |
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*/ |
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func (self *cryptoId) startHandshake(remotePubKeyDER, sessionToken []byte) (auth []byte, initNonce []byte, randomPrvKey *ecdsa.PrivateKey, randomPubKey *ecdsa.PublicKey, err error) { |
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// session init, common to both parties
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remotePubKey = crypto.ToECDSAPub(remotePubKeyDER) |
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remotePubKey := crypto.ToECDSAPub(remotePubKeyDER) |
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if remotePubKey == nil { |
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err = fmt.Errorf("invalid remote public key") |
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return |
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@ -70,6 +84,7 @@ func (self *cryptoId) initAuth(remotePubKeyDER, sessionToken []byte) (auth []byt |
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if sessionToken, err = ecies.ImportECDSA(self.prvKey).GenerateShared(ecies.ImportECDSAPublic(remotePubKey), sskLen, sskLen); err != nil { |
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return |
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} |
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// this will not stay here ;)
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fmt.Printf("secret generated: %v %x", len(sessionToken), sessionToken) |
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// tokenFlag = 0x00 // redundant
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} else { |
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@ -93,15 +108,14 @@ func (self *cryptoId) initAuth(remotePubKeyDER, sessionToken []byte) (auth []byt |
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var sharedSecret = Xor(sessionToken, initNonce) |
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// generate random keypair to use for signing
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var ecdsaRandomPrvKey *ecdsa.PrivateKey |
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if ecdsaRandomPrvKey, err = crypto.GenerateKey(); err != nil { |
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if randomPrvKey, err = crypto.GenerateKey(); err != nil { |
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return |
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} |
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// sign shared secret (message known to both parties): shared-secret
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var signature []byte |
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// signature = sign(ecdhe-random, shared-secret)
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// uses secp256k1.Sign
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if signature, err = crypto.Sign(sharedSecret, ecdsaRandomPrvKey); err != nil { |
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if signature, err = crypto.Sign(sharedSecret, randomPrvKey); err != nil { |
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return |
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} |
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fmt.Printf("signature generated: %v %x", len(signature), signature) |
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@ -110,7 +124,7 @@ func (self *cryptoId) initAuth(remotePubKeyDER, sessionToken []byte) (auth []byt |
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// signed-shared-secret || H(ecdhe-random-pubk) || pubk || nonce || 0x0
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copy(msg, signature) // copy signed-shared-secret
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// H(ecdhe-random-pubk)
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copy(msg[sigLen:sigLen+keyLen], crypto.Sha3(crypto.FromECDSAPub(&ecdsaRandomPrvKey.PublicKey))) |
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copy(msg[sigLen:sigLen+keyLen], crypto.Sha3(crypto.FromECDSAPub(&randomPrvKey.PublicKey))) |
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// pubkey copied to the correct segment.
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copy(msg[sigLen+keyLen:sigLen+2*keyLen], self.pubKeyDER) |
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// nonce is already in the slice
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@ -131,7 +145,7 @@ func (self *cryptoId) initAuth(remotePubKeyDER, sessionToken []byte) (auth []byt |
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} |
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// verifyAuth is called by peer if it accepted (but not initiated) the connection
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func (self *cryptoId) verifyAuth(auth, sessionToken []byte, remotePubKey *ecdsa.PublicKey) (authResp []byte, respNonce []byte, initNonce []byte, remoteRandomPubKey *ecdsa.PublicKey, err error) { |
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func (self *cryptoId) respondToHandshake(auth, sessionToken []byte, remotePubKey *ecdsa.PublicKey) (authResp []byte, respNonce []byte, initNonce []byte, randomPrvKey *ecdsa.PrivateKey, err error) { |
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var msg []byte |
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fmt.Printf("encrypted message received: %v %x\n used pubkey: %x\n", len(auth), auth, crypto.FromECDSAPub(self.pubKey)) |
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// they prove that msg is meant for me,
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@ -167,7 +181,7 @@ func (self *cryptoId) verifyAuth(auth, sessionToken []byte, remotePubKey *ecdsa. |
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return |
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} |
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// convert to ECDSA standard
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remoteRandomPubKey = crypto.ToECDSAPub(remoteRandomPubKeyDER) |
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remoteRandomPubKey := crypto.ToECDSAPub(remoteRandomPubKeyDER) |
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if remoteRandomPubKey == nil { |
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err = fmt.Errorf("invalid remote public key") |
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return |
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@ -181,13 +195,12 @@ func (self *cryptoId) verifyAuth(auth, sessionToken []byte, remotePubKey *ecdsa. |
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return |
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} |
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// generate random keypair for session
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var ecdsaRandomPrvKey *ecdsa.PrivateKey |
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if ecdsaRandomPrvKey, err = crypto.GenerateKey(); err != nil { |
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if randomPrvKey, err = crypto.GenerateKey(); err != nil { |
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return |
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} |
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// responder auth message
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// E(remote-pubk, ecdhe-random-pubk || nonce || 0x0)
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copy(resp[:keyLen], crypto.FromECDSAPub(&ecdsaRandomPrvKey.PublicKey)) |
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copy(resp[:keyLen], crypto.FromECDSAPub(&randomPrvKey.PublicKey)) |
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// nonce is already in the slice
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resp[resLen-1] = tokenFlag |
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@ -200,7 +213,7 @@ func (self *cryptoId) verifyAuth(auth, sessionToken []byte, remotePubKey *ecdsa. |
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return |
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} |
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func (self *cryptoId) verifyAuthResp(auth []byte) (respNonce []byte, remoteRandomPubKey *ecdsa.PublicKey, tokenFlag bool, err error) { |
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func (self *cryptoId) completeHandshake(auth []byte) (respNonce []byte, remoteRandomPubKey *ecdsa.PublicKey, tokenFlag bool, err error) { |
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var msg []byte |
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// they prove that msg is meant for me,
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// I prove I possess private key if i can read it
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@ -221,12 +234,12 @@ func (self *cryptoId) verifyAuthResp(auth []byte) (respNonce []byte, remoteRando |
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return |
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} |
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func (self *cryptoId) newSession(initNonce, respNonce, auth []byte, remoteRandomPubKey *ecdsa.PublicKey) (sessionToken []byte, rw *secretRW, err error) { |
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func (self *cryptoId) newSession(initNonce, respNonce, auth []byte, privKey *ecdsa.PrivateKey, remoteRandomPubKey *ecdsa.PublicKey) (sessionToken []byte, rw *secretRW, err error) { |
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// 3) Now we can trust ecdhe-random-pubk to derive new keys
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//ecdhe-shared-secret = ecdh.agree(ecdhe-random, remote-ecdhe-random-pubk)
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var dhSharedSecret []byte |
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dhSharedSecret, err = ecies.ImportECDSA(self.prvKey).GenerateShared(ecies.ImportECDSAPublic(remoteRandomPubKey), sskLen, sskLen) |
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if err != nil { |
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pubKey := ecies.ImportECDSAPublic(remoteRandomPubKey) |
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if dhSharedSecret, err = ecies.ImportECDSA(privKey).GenerateShared(pubKey, sskLen, sskLen); err != nil { |
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return |
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} |
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// shared-secret = crypto.Sha3(ecdhe-shared-secret || crypto.Sha3(nonce || initiator-nonce))
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