public static byte[] ComputeClientProof(Mpi safePrimeModulus, Mpi generator, string username, byte[] salt, Mpi clientPublicKey, Mpi serverPublicKey, Mpi sharedKey, string authId, string options, HashAlgorithm hashAlgorithm)
{
byte[] n = safePrimeModulus.ToBytes(),
g = generator.ToBytes(),
u = Encoding.UTF8.GetBytes(username), s = salt,
a = clientPublicKey.ToBytes(), b = serverPublicKey.ToBytes(),
k = sharedKey.ToBytes(), i = Encoding.UTF8.GetBytes(authId),
l = Encoding.UTF8.GetBytes(options);
HashAlgorithm h = hashAlgorithm;
byte[] seq = new ByteBuilder()
.Append(Xor(h.ComputeHash(n), h.ComputeHash(g)))
.Append(h.ComputeHash(u))
.Append(s)
.Append(a)
.Append(b)
.Append(k)
.Append(h.ComputeHash(i))
.Append(h.ComputeHash(l))
.ToArray();
return h.ComputeHash(seq);
}
public static byte[] ComputeServerProof(Mpi clientPublicKey, byte[] clientProof, Mpi sharedKey, string authId, string options, string sid, uint ttl, HashAlgorithm hashAlgorithm)
{
byte[] a =
clientPublicKey.ToBytes(),
m1 = clientProof,
k = sharedKey.ToBytes(),
i = Encoding.UTF8.GetBytes(authId),
o = Encoding.UTF8.GetBytes(options),
sid_ = Encoding.UTF8.GetBytes(sid);
HashAlgorithm h = hashAlgorithm;
byte[] seq = new ByteBuilder()
.Append(a)
.Append(m1)
.Append(k)
.Append(h.ComputeHash(i))
.Append(h.ComputeHash(o))
.Append(sid_)
.Append(ttl, true)
.ToArray();
return h.ComputeHash(seq);
}
public static Mpi ComputeSharedKey(byte[] salt, string username, string password, Mpi clientPublicKey, Mpi serverPublicKey, Mpi clientPrivateKey, Mpi generator, Mpi safePrimeModulus, HashAlgorithm hashAlgorithm)
{
byte[] u = hashAlgorithm.ComputeHash(new ByteBuilder()
.Append(clientPublicKey.ToBytes())
.Append(serverPublicKey.ToBytes())
.ToArray());
byte[] up = hashAlgorithm.ComputeHash(Encoding.UTF8.GetBytes(username + ":" + password)), sup = new ByteBuilder().Append(salt).Append(up).ToArray(), x = hashAlgorithm.ComputeHash(sup);
Mpi u_ = new Mpi(u), x_ = new Mpi(x);
ts.TraceInformation("ComputeSharedKey: _u = " + u_.Value.ToString("X"));
ts.TraceInformation("ComputeSharedKey: _x = " + x_.Value.ToString("X"));
BigInteger base_ = BigInteger.Subtract(serverPublicKey.Value, BigInteger.Multiply(new BigInteger(3), BigInteger.ModPow(generator.Value, x_.Value, safePrimeModulus.Value)) % safePrimeModulus.Value);
if (base_.Sign < 0)
{
base_ = BigInteger.Add(base_, safePrimeModulus.Value);
}
ts.TraceInformation("ComputeSharedKey: _base = " + base_.ToString("X"));
BigInteger gx = BigInteger.ModPow(generator.Value, x_.Value, safePrimeModulus.Value), gx3 = BigInteger.Multiply(new BigInteger(3), gx) % safePrimeModulus.Value;
ts.TraceInformation("ComputeSharedKey: gx = " + gx.ToString("X"));
BigInteger @base = BigInteger.Subtract(serverPublicKey.Value, gx3) % safePrimeModulus.Value;
if (@base.Sign < 0)
{
@base = BigInteger.Add(@base, safePrimeModulus.Value);
}
ts.TraceInformation("ComputeSharedKey: @base = " + @base.ToString("X"));
BigInteger exp = BigInteger.Add(clientPrivateKey.Value, BigInteger.Multiply(u_.Value, x_.Value)),
s = BigInteger.ModPow(base_, exp, safePrimeModulus.Value);
ts.TraceInformation("ComputeSharedKey: exp = " + exp.ToString("X"));
ts.TraceInformation("ComputeSharedKey: S = " + s.ToString("X"));
return new Mpi(hashAlgorithm.ComputeHash(new Mpi(s).ToBytes()));
}