public ServerAuthResponse AuthenticateClient(string username, BigInteger A)
{
if (A == 0)
{
throw new AuthenticationFailedException();
}
this.A = A;
var random = new Random();
BigInteger b = random.Next(int.MaxValue / 2, int.MaxValue);
B = factors.k * v + BigInteger.ModPow(factors.g, b, factors.N);
var u = ShaHashing.GenerateSha512Hash(A + B.ToString());
if (u == 0)
{
throw new ConnectionInterruptedException();
}
S = BigInteger.ModPow(
A * BigInteger.ModPow(v, u, factors.N),
b,
factors.N);
K = ShaHashing.GenerateSha512Hash(S.ToString());
SRPManager.DisplayAuthenticationOnServerSide(b, B, u, S, K);
return(new ServerAuthResponse(s, B));
}
public void Registration()
{
generateS();
x = ShaHashing.GenerateSha512Hash(s + password);
v = BigInteger.ModPow(factors.g, x, factors.N);
server.RegisterClient(username, s, v);
SRPManager.DisplayRegistration(s, x, v);
}
public void GenerateConfirmation()
{
var M = ShaHashing.GenerateSha512Hash(
XOR(
ShaHashing.GenerateSha512Hash(factors.N.ToString()).ToByteArray(),
ShaHashing.GenerateSha512Hash(factors.g.ToString()).ToByteArray())
+ ShaHashing.GenerateSha512Hash(username)
+ S + A.ToString() + B.ToString() + factors.k);
var serverR = server.ConfirmClientAccess(M);
var clientR = ShaHashing.GenerateSha512Hash(
A.ToString() + M.ToString() + K.ToString());
if (clientR != serverR)
{
throw new ConfirmationFailedException();
}
SRPManager.DisplayConfirmationOnClientSide(clientR);
}
public BigInteger ConfirmClientAccess(BigInteger clientM)
{
var serverM = ShaHashing.GenerateSha512Hash(
XOR(
ShaHashing.GenerateSha512Hash(factors.N.ToString()).ToByteArray(),
ShaHashing.GenerateSha512Hash(factors.g.ToString()).ToByteArray())
+ ShaHashing.GenerateSha512Hash(username)
+ S + A.ToString() + B.ToString() + factors.k);
if (serverM != clientM)
{
throw new ConfirmationFailedException();
}
var R = ShaHashing.GenerateSha512Hash(
A.ToString() + serverM.ToString() + K.ToString());
SRPManager.DisplayConfirmationOnServerSide(clientM, serverM, R);
return(R);
}
public void Authentication()
{
var random = new Random();
BigInteger a = random.Next(int.MaxValue / 2, int.MaxValue);
A = BigInteger.ModPow(factors.g, a, factors.N);
SRPManager.DisplayAuthenticationBeforeSending(a, A);
var response = server.AuthenticateClient(username, A);
B = response.B;
if (B == 0)
{
throw new AuthenticationFailedException();
}
var u = ShaHashing.GenerateSha512Hash(A + B.ToString());
if (u == 0)
{
throw new ConnectionInterruptedException();
}
S = BigInteger.ModPow(
B - factors.k * BigInteger.ModPow(factors.g, x, factors.N),
(a + BigInteger.Multiply(u, x)),
factors.N);
K = ShaHashing.GenerateSha512Hash(S.ToString());
SRPManager.DisplayAuthenticationAfterSending(u, S, K);
GenerateConfirmation();
}