simontime

private static byte[] PBKDF2(int Len, byte[] Passphrase, byte[] Salt, int IterCount)
{
    using (var HMAC = new HMACSHA256(Passphrase))
    {
        byte[] ExtKey = new byte[Salt.Length + 4];
        Buffer.BlockCopy(Salt, 0, ExtKey, 0, Salt.Length);

        using (var Strm = new MemoryStream())
        {
            for (int i = 0; i < Len >> 5; i++)