/// <summary>
/// Calculates a pairwise master key
/// </summary>
/// <param name="psk">Pre-shared key</param>
/// <param name="ssid">SSID</param>
/// <param name="pmk_len">Length of PMK to generate</param>
/// <returns>Pairwise master key</returns>
public static byte[] CalculatePMK(byte[] psk, byte[] ssid, int pmk_len = 32)
{
var pbkdf2 = new Rfc2898DeriveBytes(psk, /*ssid*/new byte[8], 4096);
// This reflection crap is required because there's an arbitrary restriction that the salt must be at least 8 bytes
var oldSaltProp = pbkdf2.GetType().GetField("m_salt", BindingFlags.NonPublic | BindingFlags.Instance);
var newSaltProp = pbkdf2.GetType().GetField("_salt", BindingFlags.NonPublic | BindingFlags.Instance);
(oldSaltProp ?? newSaltProp).SetValue(pbkdf2, ssid);
// pbkdf2.Reset(); //To officially complete the reflection trick, the private method Initialize() should be called. That's all Reset() does.
// But I don't think it's needed because we haven't hashed anything yet.
return pbkdf2.GetBytes(pmk_len);
}