public void AuthValidSignAndRecoverEip8()
{
// Generate all needed keypairs.
EthereumEcdsa localPrivateKey = EthereumEcdsa.Generate();
EthereumEcdsa ephemeralPrivateKey = EthereumEcdsa.Generate();
EthereumEcdsa receiverPrivateKey = EthereumEcdsa.Generate();
// Create an RLPx auth packet and sign it.
RLPxAuthEIP8 authPacket = new RLPxAuthEIP8();
authPacket.Sign(localPrivateKey, ephemeralPrivateKey, receiverPrivateKey, null);
// Serialize and deserialize it.
byte[] serializedData = authPacket.Serialize();
RLPxAuthEIP8 deserializedPacket = new RLPxAuthEIP8(serializedData);
// Verify all matches between our serialized/deserialized object data.
Assert.Equal(authPacket.Nonce.ToHexString(), deserializedPacket.Nonce.ToHexString());
Assert.Equal(authPacket.PublicKey.ToHexString(), deserializedPacket.PublicKey.ToHexString());
Assert.Equal(authPacket.R.ToHexString(), deserializedPacket.R.ToHexString());
Assert.Equal(authPacket.S.ToHexString(), deserializedPacket.S.ToHexString());
Assert.Equal(authPacket.V, deserializedPacket.V);
// Try to recover the public key
EthereumEcdsa recoveredEphemeralPublicKey = deserializedPacket.RecoverDataFromSignature(receiverPrivateKey).remoteEphemeralPublicKey;
// Verify our public key hashes match
Assert.Equal(ephemeralPrivateKey.GetPublicKeyHash().ToHexString(), recoveredEphemeralPublicKey.GetPublicKeyHash().ToHexString());
}
/// <summary>
/// Verifies the provided encrypted serialized authentication data received from the initiator.
/// If verification fails, an appropriate exception will be thrown. If no exception is thrown,
/// the verification has succeeded.
/// </summary>
/// <param name="authData">The encrypted serialized authentication data to verify.</param>
public void VerifyAuthentication(byte[] authData)
{
// Verify this is the responder role.
if (Role != RLPxSessionRole.Responder)
{
throw new Exception("RLPx auth data should only be verified by the responder.");
}
// Verify the session state is correct.
if (SessionState != RLPxSessionState.Initial)
{
throw new Exception("RLPx auth verification should only be performed on a new session.");
}
// Try to deserialize the data as a standard authentication packet.
// The data is currently encrypted serialized data, so it will also need to be decrypted.
RLPxAuthBase authenticationMessage = null;
try
{
// Set the auth data
AuthData = authData.Slice(0, AUTH_STANDARD_ENCRYPTED_SIZE);
// The authentication data can simply be decrypted without any shared mac.
byte[] decryptedAuthData = Ecies.Decrypt(LocalPrivateKey, AuthData, null);
// Try to parse the decrypted authentication data.
authenticationMessage = new RLPxAuthStandard(decryptedAuthData);
UsingEIP8Authentication = false;
// Set the remote version
RemoteVersion = MAX_SUPPORTED_VERSION;
}
catch (Exception authStandardEx)
{
try
{
// EIP8 has a uint16 denoting encrypted data size, and the data to decrypt follows.
Memory <byte> authDataMem = authData;
Memory <byte> sharedMacDataMem = authDataMem.Slice(0, 2);
ushort encryptedSize = (ushort)BigIntegerConverter.GetBigInteger(sharedMacDataMem.Span, false, sharedMacDataMem.Length);
Memory <byte> encryptedData = authDataMem.Slice(2, encryptedSize);
// Set our auth data
AuthData = authDataMem.Slice(0, sharedMacDataMem.Length + encryptedSize).ToArray();
// Split the shared mac from the authentication data
byte[] decryptedAuthData = Ecies.Decrypt(LocalPrivateKey, encryptedData, sharedMacDataMem);
// Try to parse the decrypted EIP8 authentication data.
RLPxAuthEIP8 authEip8Message = new RLPxAuthEIP8(decryptedAuthData);
UsingEIP8Authentication = true;
// Set the generic authentication data object.
authenticationMessage = authEip8Message;
// Set the remote version
RemoteVersion = authEip8Message.Version;
}
catch (Exception authEip8Ex)
{
string exceptionMessage = "Could not deserialize RLPx auth data in either standard or EIP8 format.\r\n";
exceptionMessage += $"Standard Auth Error: {authStandardEx.Message}\r\n";
exceptionMessage += $"EIP8 Auth Error: {authEip8Ex.Message}";
throw new Exception(exceptionMessage);
}
}
// Set the initiator nonce
InitiatorNonce = authenticationMessage.Nonce;
// Set the remote public key.
RemotePublicKey = EthereumEcdsa.Create(authenticationMessage.PublicKey, EthereumEcdsaKeyType.Public);
// Try to recover the public key (with the "receiver" private key, which in this case is our local private key, since our role is responder).
// If this fails, it will throw an exception as we expect this method to if any failure occurs.
(EthereumEcdsa remoteEphermalPublicKey, uint?chainId) = authenticationMessage.RecoverDataFromSignature(LocalPrivateKey);
RemoteEphermalPublicKey = remoteEphermalPublicKey;
// TODO: Verify the chain id.
// Set the session state
SessionState = RLPxSessionState.AuthenticationCompleted;
}
/// <summary>
/// Creates authentication data to send to the responder.
/// </summary>
/// <param name="receiverPublicKey">The responder/receiver's public key.</param>
/// <param name="nonce">The nonce to use for the authentication data. If null, new data is generated.</param>
/// <returns>Returns the encrypted serialized authentication data.</returns>
public byte[] CreateAuthentiation(EthereumEcdsa receiverPublicKey, byte[] nonce = null)
{
// Verify this is the initiator role.
if (Role != RLPxSessionRole.Initiator)
{
throw new Exception("RLPx auth data should only be created by the initiator.");
}
// Verify the session state is correct.
if (SessionState != RLPxSessionState.Initial)
{
throw new Exception("RLPx auth creation should only be performed on a new session.");
}
// If the nonce is null, generate a new one.
nonce = nonce ?? GenerateNonce();
// Set our initiator nonce
InitiatorNonce = nonce;
// Set the remote public key
RemotePublicKey = receiverPublicKey;
// Create a new authentication message based off of our configured setting.
RLPxAuthBase authMessage = null;
if (UsingEIP8Authentication)
{
// Create our EIP8 authentication message.
authMessage = new RLPxAuthEIP8()
{
Nonce = InitiatorNonce,
Version = MAX_SUPPORTED_VERSION,
};
}
else
{
// Create our standard authentication message.
authMessage = new RLPxAuthStandard()
{
Nonce = InitiatorNonce,
};
}
// Sign the authentication message
authMessage.Sign(LocalPrivateKey, LocalEphemeralPrivateKey, RemotePublicKey, ChainId);
// Serialize the authentication data
byte[] serializedData = authMessage.Serialize();
// Encrypt the data accordingly (standard uses no shared mac data, EIP8 has 2 bytes which prefix the resulting encrypted data).
if (UsingEIP8Authentication)
{
// Obtain two bytes of mac data by EIP8 standards (big endian 16-bit unsigned integer equal to the size of the resulting ECIES encrypted data).
// We can calculate this as the amount of overhead data ECIES adds is static in size.
byte[] sharedMacData = BigIntegerConverter.GetBytes(serializedData.Length + Ecies.ECIES_ADDITIONAL_OVERHEAD, 2);
// Encrypt the serialized data with the shared mac data, and prefix the result with it.
byte[] encryptedSerializedData = Ecies.Encrypt(RemotePublicKey, serializedData, sharedMacData);
AuthData = sharedMacData.Concat(encryptedSerializedData);
}
else
{
// Encrypt it using ECIES without any shared mac data.
AuthData = Ecies.Encrypt(RemotePublicKey, serializedData, null);
}
// Set the session state
SessionState = RLPxSessionState.AuthenticationCompleted;
// Return the auth data
return(AuthData);
}
