قراءة وكتابة من ملف مشفر

يمكنك إستخدام الفضاء Cryptography حيث يمكنك إستخدام خوارزميات RSA و الخوارزميات الأخرى .... إستخدم الMSDN لشرح أوفى عن الموضوع ....

هذا مثال منه :

using System;
using System.Security.Cryptography;
using System.Text;

class RSACSPSample
{

	static void Main()
	{
		try
		{
			//Create a UnicodeEncoder to convert between byte array and string.
			UnicodeEncoding ByteConverter = new UnicodeEncoding();

			//Create byte arrays to hold original, encrypted, and decrypted data.
			byte[] dataToEncrypt = ByteConverter.GetBytes("Data to Encrypt");
			byte[] encryptedData;
			byte[] decryptedData;

			//Create a new instance of RSACryptoServiceProvider to generate
			//public and private key data.
			RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

			//Pass the data to ENCRYPT, the public key information 
			//(using RSACryptoServiceProvider.ExportParameters(false),
			//and a boolean flag specifying no OAEP padding.
			encryptedData = RSAEncrypt(dataToEncrypt,RSA.ExportParameters(false), false);

			//Pass the data to DECRYPT, the private key information 
			//(using RSACryptoServiceProvider.ExportParameters(true),
			//and a boolean flag specifying no OAEP padding.
			decryptedData = RSADecrypt(encryptedData,RSA.ExportParameters(true), false);

			//Display the decrypted plaintext to the console. 
			Console.WriteLine("Decrypted plaintext: {0}", ByteConverter.GetString(decryptedData));
		}
		catch(ArgumentNullException)
		{
			//Catch this exception in case the encryption did
			//not succeed.
			Console.WriteLine("Encryption failed.");

		}
	}

	static public byte[] RSAEncrypt(byte[] DataToEncrypt, RSAParameters RSAKeyInfo, bool DoOAEPPadding)
	{
		try
		{	
			//Create a new instance of RSACryptoServiceProvider.
			RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

			//Import the RSA Key information. This only needs
			//toinclude the public key information.
			RSA.ImportParameters(RSAKeyInfo);

			//Encrypt the passed byte array and specify OAEP padding.  
			//OAEP padding is only available on Microsoft Windows XP or
			//later.  
			return RSA.Encrypt(DataToEncrypt, DoOAEPPadding);
		}
		//Catch and display a CryptographicException  
		//to the console.
		catch(CryptographicException e)
		{
			Console.WriteLine(e.Message);

			return null;
		}

	}

	static public byte[] RSADecrypt(byte[] DataToDecrypt, RSAParameters RSAKeyInfo,bool DoOAEPPadding)
	{
		try
		{
			//Create a new instance of RSACryptoServiceProvider.
			RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

			//Import the RSA Key information. This needs
			//to include the private key information.
			RSA.ImportParameters(RSAKeyInfo);

			//Decrypt the passed byte array and specify OAEP padding.  
			//OAEP padding is only available on Microsoft Windows XP or
			//later.  
			return RSA.Decrypt(DataToDecrypt, DoOAEPPadding);
		}
		//Catch and display a CryptographicException  
		//to the console.
		catch(CryptographicException e)
		{
			Console.WriteLine(e.ToString());

			return null;
		}

	}
}