AES-Verschlüsselung auf große Dateien

So habe ich eine ziemlich schnelle und niedrigen Speicherverbrauch version:

Ich benutze eine "temporäre buffer" und auch "use a random salt und speichern Sie es mit der Chiffretext".

Zum verschlüsseln:

private void AES_Encrypt(string inputFile, string password)
    {
        //http://stackoverflow.com/questions/27645527/aes-encryption-on-large-files

        //generate random salt
        byte[] salt = GenerateRandomSalt();

        //create output file name
        FileStream fsCrypt = new FileStream(inputFile + ".aes", FileMode.Create);

        //convert password string to byte arrray
        byte[] passwordBytes = System.Text.Encoding.UTF8.GetBytes(password);

        //Set Rijndael symmetric encryption algorithm
        RijndaelManaged AES = new RijndaelManaged();
        AES.KeySize = 256;
        AES.BlockSize = 128;
        AES.Padding = PaddingMode.PKCS7;

        //http://stackoverflow.com/questions/2659214/why-do-i-need-to-use-the-rfc2898derivebytes-class-in-net-instead-of-directly
        //"What it does is repeatedly hash the user password along with the salt." High iteration counts.
        var key = new Rfc2898DeriveBytes(passwordBytes, salt, 50000);
        AES.Key = key.GetBytes(AES.KeySize / 8);
        AES.IV = key.GetBytes(AES.BlockSize / 8);

        //Cipher modes: http://security.stackexchange.com/questions/52665/which-is-the-best-cipher-mode-and-padding-mode-for-aes-encryption
        AES.Mode = CipherMode.CFB;

        //write salt to the begining of the output file, so in this case can be random every time
        fsCrypt.Write(salt, 0, salt.Length);

        CryptoStream cs = new CryptoStream(fsCrypt, AES.CreateEncryptor(), CryptoStreamMode.Write);

        FileStream fsIn = new FileStream(inputFile, FileMode.Open);

        //create a buffer (1mb) so only this amount will allocate in the memory and not the whole file
        byte[] buffer = new byte[1048576];
        int read;

        try
        {
            while ((read = fsIn.Read(buffer, 0, buffer.Length)) > 0)
            {
                Application.DoEvents(); //-> for responsive GUI, using Task will be better!
                cs.Write(buffer, 0, read);
            }

            //close up
            fsIn.Close();

        }
        catch (Exception ex)
        {
            Debug.WriteLine("Error: " + ex.Message);
        }
        finally
        {
            cs.Close();
            fsCrypt.Close();
        }
    }

Entschlüsseln:

private void AES_Decrypt(string inputFile, string password)
    {
        //todo:
        //- create error message on wrong password
        //- on cancel: close and delete file
        //- on wrong password: close and delete file!
        //- create a better filen name
        //- could be check md5 hash on the files but it make this slow

        byte[] passwordBytes = System.Text.Encoding.UTF8.GetBytes(password);
        byte[] salt = new byte[32];

        FileStream fsCrypt = new FileStream(inputFile, FileMode.Open);
        fsCrypt.Read(salt, 0, salt.Length);

        RijndaelManaged AES = new RijndaelManaged();
        AES.KeySize = 256;
        AES.BlockSize = 128;
        var key = new Rfc2898DeriveBytes(passwordBytes, salt, 50000);
        AES.Key = key.GetBytes(AES.KeySize / 8);
        AES.IV = key.GetBytes(AES.BlockSize / 8);
        AES.Padding = PaddingMode.PKCS7;
        AES.Mode = CipherMode.CFB;

        CryptoStream cs = new CryptoStream(fsCrypt, AES.CreateDecryptor(), CryptoStreamMode.Read);

        FileStream fsOut = new FileStream(inputFile + ".decrypted", FileMode.Create);

        int read;
        byte[] buffer = new byte[1048576];

        try
        {
            while ((read = cs.Read(buffer, 0, buffer.Length)) > 0)
            {
                Application.DoEvents();
                fsOut.Write(buffer, 0, read);
            }
        }
        catch (System.Security.Cryptography.CryptographicException ex_CryptographicException)
        {
            Debug.WriteLine("CryptographicException error: " + ex_CryptographicException.Message);
        }
        catch (Exception ex)
        {
            Debug.WriteLine("Error: " + ex.Message);
        }

        try
        {
            cs.Close();
        }
        catch (Exception ex)
        {
            Debug.WriteLine("Error by closing CryptoStream: " + ex.Message);
        }
        finally
        {
            fsOut.Close();
            fsCrypt.Close();
        }
    }

Generieren random salt:

        public static byte[] GenerateRandomSalt()
    {
        //Source: http://www.dotnetperls.com/rngcryptoserviceprovider
        byte[] data = new byte[32];

        using (RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider())
        {
            //Ten iterations.
            for (int i = 0; i < 10; i++)
            {
                //Fill buffer.
                rng.GetBytes(data);
            }
        }
        return data;
    }