/// <summary>
/// Respond to the server's challenge with a proof of password.
/// </summary>
/// <returns>The to challenge.</returns>
/// <param name="password">Password.</param>
/// <param name="identity">Identity.</param>
/// <param name="salt">Salt.</param>
/// <param name="Bhex">Bhex.</param>
public static Meteor.ChallengeResponse RespondToChallenge(string password, string identity, string salt, string Bhex)
{
BigInteger B = new BigInteger (Bhex, 16);
BigInteger u = new BigInteger (Hash (Ahex + Bhex), 16);
BigInteger x = new BigInteger (Hash (salt + Hash (identity + ":" + password)),16);
BigInteger kgx = k * (g.modPow (x, N));
BigInteger aux = a + (u * x);
S = (B - kgx).modPow (aux, N);
string Shex = S.ToString(16).ToLowerInvariant().TrimStart('0');
string M = Hash (Ahex + Bhex + Shex);
HAMK = Hash (Ahex + M + Shex);
return new Meteor.ChallengeResponse () {
M = M.ToLowerInvariant().TrimStart('0')
};
}
/// <summary>
/// Generate a new SRP verifier. Password is the plaintext password.
/// </summary>
/// <returns>The verifier.</returns>
/// <param name="password">Password.</param>
//original: (didn't work with 3.5 .Net compiler and was annoying to keep switching to 4.0
//public static Meteor.Verifier GenerateVerifier(string password, string identity = null, string salt = null)
public static Meteor.Verifier GenerateVerifier(string password, string identity, string salt)
{
if (identity == null)
{
BigInteger i = new BigInteger ();
i.genRandomBits (36);
identity = i.ToString(16).ToLowerInvariant().TrimStart('0');
}
if (salt == null)
{
BigInteger s = new BigInteger ();
s.genRandomBits (36);
salt = s.ToString(16).ToLowerInvariant().TrimStart('0');
}
string x = Hash (salt + Hash (identity + ":" + password));
BigInteger xi = new BigInteger (x, 16);
BigInteger v = g.modPow (xi, N);
return new Meteor.Verifier () {
identity = identity,
salt = salt,
verifier = v.ToString(16).ToLowerInvariant().TrimStart('0')
};
}
