class MyClass {
    public static void weakEncryption()
    {
        DES des = new DESCryptoServiceProvider();
        CryptoStream encStream = new CryptoStream(fout, des.CreateEncryptor(desKey, desIV), CryptoStreamMode.Write);

    }
}

class MyClass {
    public static void strongEncryption()
    {
        // Safe: using AES instead of DES
        using (Aes aes = Aes.Create())
        {
            CryptoStream encStream = new CryptoStream(fout, aes.CreateEncryptor(), CryptoStreamMode.Write);
        }
    }
}