Add progress bar using Cryptostream not with FileStream to Increase the speed of the Encryption

Question

Hi everyone,
sorry, is it possible to use CryptoStream class with Progress bar directly when Encrypt file ?
Because, when i loop using fileStream.Read to increment the value for Pogress bar and write the file it takes a time, especially when the file is more than 2 MB.

This is my code:
Speed encryption without using filestream but no progress bar, i don't know where to put the background work propriety.

	public  byte[] AES_Encrypt(byte[] fileContent, byte[] mtpass, string ifile)  
	{					  
		byte[] salt_Bytes = new byte[] {10, 20, 30, 40, 50, 60, 70, 80};   
		RijndaelManaged AES = new RijndaelManaged();  
		AES.KeySize = 256;  
		AES.BlockSize = 128;  
		var key = new Rfc2898DeriveBytes(mtpass, salt_Bytes, 1000);  
		AES.Key = key.GetBytes(AES.KeySize / 8);  
		AES.IV = key.GetBytes(AES.BlockSize / 8);  
		AES.Mode = CipherMode.CBC;  
		AES.Padding = PaddingMode.Zeros;  

	//SPEED INCRYPTION WITHOUT PROGRESS BAR  
	  
		MemoryStream mem = new MemoryStream();  
		CryptoStream fich_crypt_mem = new CryptoStream(mem, AES.CreateEncryptor(), CryptoStreamMode.Write);  
		  
	//MAYBE HERE TO ADD THE CODE FOR CHANGE THE VALUE FOR PROGRESS BAR   
		fich_crypt_mem.Write(fileContent, 0, fileContent.Length);  
	  
		fich_crypt_mem.Close();  
		return  mem.ToArray();  
	}  

The code: using fileStream and Progress bar work fine, but slow encryption:

public byte[] AES_Encrypt(byte[] fileContent, byte[] mtpass, string ifile)
{
//AES KEY GENERATE(SAME)

// PROGRESS BAR WORK BUT ENCRYPTION SLOW  
	  
MemoryStream mem = new MemoryStream();  
CryptoStream fich_crypt_mem = new CryptoStream(mem, AES.CreateEncryptor(), CryptoStreamMode.Write);  
  
// USING FileStream TO CHANGE THE VALUE OF PROGRESS BAR AND WRITE THE ENCRYPT FILE  
FileStream fsIn = new FileStream(ifile, FileMode.Open);  

int data;  
  
double counter = 1;  
  
while ((data = fsIn.ReadByte()) != -1) //Loop FileStream.Read  
{  
	fich_crypt_mem.WriteByte((byte)data);  
  
	myBWorker.ReportProgress((int)((counter / fsIn.Length) * 100)); // progressbar using BackgroundWorker  
	counter++;  
}  

}

Thanks, and sorry for my English is not good.

Answer 1

I'd assume it was because you're reading/writing bytes one at a time rather than reading a chunk of them all together into a buffer. It's quite inefficient, particularly for the synchronous ReadByte & WriteByte methods.

You could look at reading/writing a sequence of bytes in one go (say 1KB?) and that will likely improve things. It would probably be a good idea to opt for the asynchronous versions of these methods too (i.e. ReadAsync instead of Read & WriteAsync instead of Write).

Marc Gravell has added a concise example (of the synchronous method of doing this) to this SO post:
https://stackoverflow.com/questions/2030847/best-way-to-read-a-large-file-into-a-byte-array-in-c#answer-2030971

In this example you'd replace your double counter for a int totalBytesRead and before you report your progress event you would do totalBytesRead += bytesRead