/// <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());
}