Create 256 bit AES symmetric key

private static readonly byte[] Salt = new byte[] { 10, 20, 30, 40, 50, 60, 70, 80 };

private static byte[] CreateKey(string password, int keyBytes = 32)
{
    const int Iterations = 300;
    var keyGenerator = new Rfc2898DeriveBytes(password, Salt, Iterations);
    return keyGenerator.GetBytes(keyBytes);
}