/// <summary>
/// Compute client public ephemeral value (A)
/// </summary>
public static byte[] ComputeClientEphemeral(byte[] clientPrivateEphemeral) // a
{
// A= g^a (mod N)
NetBigInteger a = new NetBigInteger(NetUtility.ToHexString(clientPrivateEphemeral), 16);
NetBigInteger retval = g.ModPow(a, N);
return(retval.ToByteArrayUnsigned());
}
public static byte[] ComputeServerSessionValue(byte[] clientPublicEphemeral, byte[] verifier, byte[] udata, byte[] serverPrivateEphemeral)
{
// S = (Av^u) ^ b (mod N)
var A = new NetBigInteger(NetUtility.ToHexString(clientPublicEphemeral), 16);
var v = new NetBigInteger(NetUtility.ToHexString(verifier), 16);
var u = new NetBigInteger(NetUtility.ToHexString(udata), 16);
var b = new NetBigInteger(NetUtility.ToHexString(serverPrivateEphemeral), 16);
NetBigInteger retval = v.ModPow(u, N).Multiply(A).Mod(N).ModPow(b, N).Mod(N);
return(retval.ToByteArrayUnsigned());
}
/// <summary>
/// Compute multiplier (k)
/// </summary>
private static NetBigInteger ComputeMultiplier()
{
string one = NetUtility.ToHexString(N.ToByteArrayUnsigned());
string two = NetUtility.ToHexString(g.ToByteArrayUnsigned());
string ccstr = one + two.PadLeft(one.Length, '0');
var cc = NetUtility.HexToBytes(ccstr, stackalloc byte[ccstr.Length * 2]);
var ccHashed = NetUtility.ComputeSHAHash(cc, stackalloc byte[NetUtility.SHAHashSize]);
return(new NetBigInteger(NetUtility.ToHexString(ccHashed), 16));
}
/// <summary>
/// Compute multiplier (k)
/// </summary>
private static NetBigInteger ComputeMultiplier()
{
string one = NetUtility.ToHexString(N.ToByteArrayUnsigned());
string two = NetUtility.ToHexString(g.ToByteArrayUnsigned());
string ccstr = one + two.PadLeft(one.Length, '0');
byte[] cc = NetUtility.ToByteArray(ccstr);
var ccHashed = NetUtility.ComputeSHAHash(cc);
return(new NetBigInteger(NetUtility.ToHexString(ccHashed), 16));
}