/// <summary>
/// Create a response on received request.
/// </summary>
/// <param name="request">Receieved Request</param>
/// <returns></returns>
private NetSRP.Response ResponseFromRequest(NetSRP.Request request)
{
if (Handshake._defaultLogonManager == null)
{
throw new NetSRP.HandShakeException("No HandShake.Passive functions are available until LogonManager is provided.");
}
if (this.HandshakeState != Handshake.State.NotInitialized && (Handshake.State.AllowResponse & this.HandshakeState) != this.HandshakeState)
{
return(_response);
}
// Set State and start timer
this.HandshakeState = Handshake.State.Responding;
_cache.ExpirationTime = DateTime.Now.AddSeconds(Handshake.ExpirationInSeconds);
if (request.A.Mod(N).IntValue == 0)
{
this.HandshakeState = Handshake.State.Failed;
throw new NetSRP.HandShakeException("Request contains invalid data", new ArgumentException("A mod N is zero."));
}
Byte[] salt;
NetBigInteger v;
// Get verifier
try
{
v = Lookup(request, out salt);
}
catch (Exception exception)
{
this.HandshakeState = Handshake.State.Failed;
throw new NetSRP.HandShakeException("LogonManager failed lookup.", exception);
}
if (v == null)
{
this.HandshakeState = Handshake.State.Denied;
throw new NetSRP.HandShakeException("Wrong username or password."); // Clearly its username.
}
// Cache request
_request = request;
_cache.UserData = _request.Username;
// Get public ket B from random private b
_cache.b = NetSRP.Getb();
_cache.B = NetSRP.CalcB(N, g, _cache.b, v);
// Create the response message
_response = new NetSRP.Response(salt, _cache.B);
// First create the key
KeyFromRequest(request.A, v);
return(_response);
}
/// <summary>
/// Processes a handshake response (initiated locally)
/// </summary>
/// <param name="msg">Incoming message with resonse data</param>
internal static NetSRP.Verification HandshakeFromPassive(NetIncomingMessage msg)
{
// Get response
NetSRP.Response response = new NetSRP.Response();
response.ExtractPacketData(msg);
// Create Verification data
return (msg.SenderConnection.Tag as Handshake).KeyFromResponse(response);
}
/// <summary>
/// Processes a handshake response (initiated locally)
/// </summary>
/// <param name="msg">Incoming message with resonse data</param>
internal static NetSRP.Verification HandshakeFromPassive(NetIncomingMessage msg)
{
// Get response
NetSRP.Response response = new NetSRP.Response();
response.ExtractPacketData(msg);
// Create Verification data
return((msg.SenderConnection.Tag as Handshake).KeyFromResponse(response));
}
/// <summary>
/// Generates Session key from response
/// </summary>
/// <param name="response"></param>
/// <response></response>
private NetSRP.Verification KeyFromResponse(NetSRP.Response response)
{
if ((Handshake.State.AllowVerificating & this.HandshakeState) != this.HandshakeState)
{
return(_verification); // Double Request
}
// When we get the response, get their public key B
if (response.B.Mod(N).IntValue == 0)
{
this.HandshakeState = Handshake.State.Failed;
throw new NetSRP.HandShakeException("Response contains invalid data", new ArgumentException("B mod N is zero."));
}
// Shared random scrambler
NetBigInteger u = NetSRP.Calcu(_cache.A, response.B);
if (u.IntValue == 0)
{
this.HandshakeState = Handshake.State.Failed;
throw new NetSRP.HandShakeException("Response contains invalid data", new ArgumentException("u is zero."));
}
// Private key x
NetBigInteger x = NetSRP.Calcx(response.Salt, _request.Username, _cache.UserData);
// Cache Response;
_response = response;
// Session key
_cache.S = NetSRP.CalcSClient(N, g, response.B, k, x, _cache.a, u);
_cache.K = NetSRP.CalcK(_cache.S);
// Create the verification
_verification = new NetSRP.Verification(NetSRP.CalcM(N, g, _request.Username, response.Salt, _cache.A, response.B, _cache.K));
// Set State
this.HandshakeState = Handshake.State.Verificating;
return(_verification);
}
/// <summary>
/// Create a response on received request.
/// </summary>
/// <param name="request">Receieved Request</param>
/// <returns></returns>
private NetSRP.Response ResponseFromRequest(NetSRP.Request request)
{
if (Handshake._defaultLogonManager == null)
throw new NetSRP.HandShakeException("No HandShake.Passive functions are available until LogonManager is provided.");
if (this.HandshakeState != Handshake.State.NotInitialized && (Handshake.State.AllowResponse & this.HandshakeState) != this.HandshakeState)
return _response;
// Set State and start timer
this.HandshakeState = Handshake.State.Responding;
_cache.ExpirationTime = DateTime.Now.AddSeconds(Handshake.ExpirationInSeconds);
if (request.A.Mod(N).IntValue == 0)
{
this.HandshakeState = Handshake.State.Failed;
throw new NetSRP.HandShakeException("Request contains invalid data", new ArgumentException("A mod N is zero."));
}
Byte[] salt;
NetBigInteger v;
// Get verifier
try
{
v = Lookup(request, out salt);
}
catch (Exception exception)
{
this.HandshakeState = Handshake.State.Failed;
throw new NetSRP.HandShakeException("LogonManager failed lookup.", exception);
}
if (v == null)
{
this.HandshakeState = Handshake.State.Denied;
throw new NetSRP.HandShakeException("Wrong username or password."); // Clearly its username.
}
// Cache request
_request = request;
_cache.UserData = _request.Username;
// Get public ket B from random private b
_cache.b = NetSRP.Getb();
_cache.B = NetSRP.CalcB(N, g, _cache.b, v);
// Create the response message
_response = new NetSRP.Response(salt, _cache.B);
// First create the key
KeyFromRequest(request.A, v);
return _response;
}
