RSA_Test1.cs - ma hoa RSA

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace ConsoleApplication1
{
    class RSA_Test1
    {
        public void GenRSA() {
            ////Generate a public/private key pair.
            //RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
            ////Save the public key information to an RSAParameters structure.
            //RSAParameters RSAKeyInfo = RSA.ExportParameters(false);
            #region Sinh khoa
            CspParameters cspParams = null;
            RSACryptoServiceProvider rsaProvider = null;
            StreamWriter publicKeyFile = null;
            StreamWriter privateKeyFile = null;
            string publicKey = "";
            string privateKey = "";


            try
            {
                // Create a new key pair on target CSP
                //cspParams = new CspParameters();
                //cspParams.ProviderType = 1; // PROV_RSA_FULL
                ////cspParams.ProviderName; // CSP name
                //cspParams.Flags = CspProviderFlags.UseArchivableKey;
                //cspParams.KeyNumber = (int)KeyNumber.Exchange;
                // c1. rsaProvider = new RSACryptoServiceProvider(cspParams);
                // c2. rsaProvider = new RSACryptoServiceProvider(2048);
                // c2  rsaProvider = new RSACryptoServiceProvider(2048,cspParams);
                // c4.
                rsaProvider = new RSACryptoServiceProvider();

                // Export public key
                publicKey = rsaProvider.ToXmlString(false);

                // Write public key to file
                //publicKeyFile = File.CreateText(publicKeyFileName);
                //publicKeyFile.Write(publicKey);

                // Export private/public key pair
                privateKey = rsaProvider.ToXmlString(true);

                Console.WriteLine("private key----------------");
                Console.WriteLine(privateKey);
                Console.WriteLine("public key-----------------");
                Console.WriteLine(publicKey);

                // Write private/public key pair to file
                //privateKeyFile = File.CreateText(privateKeyFileName);
                //privateKeyFile.Write(privateKey);
                string _message = "Syria sẽ gây ngạc nhiên cho những kẻ xâm lược như đã làm .";

                Console.WriteLine("Message: ");
                Console.WriteLine(_message);
                #endregion

                #region ma hoa
                byte[] plainBytes = null;
                byte[] encryptedBytes = null;
                byte[] decryptedBytes = null;

                plainBytes = Encoding.Unicode.GetBytes(_message);
                encryptedBytes = rsaProvider.Encrypt(plainBytes, false);

                string encrypt_message = Encoding.UTF8.GetString(encryptedBytes);
                Console.WriteLine("encrypted...");
                Console.WriteLine(encrypt_message);

                #endregion

                #region giai ma
                decryptedBytes = rsaProvider.Decrypt(encryptedBytes, false);
                string decrypted_string = Encoding.Unicode.GetString(decryptedBytes);
                Console.WriteLine("decrypted...");
                Console.WriteLine(decrypted_string);
                Console.ReadKey();

                #endregion

            }
            catch (Exception ex)
            {
                // Any errors? Show them
                Console.WriteLine("Exception generating a new key pair! More info:");
                Console.WriteLine(ex.Message);
                Console.ReadKey();
            }
            finally
            {
                // Do some clean up if needed
                if (publicKeyFile != null)
                {
                    publicKeyFile.Close();
                }
                if (privateKeyFile != null)
                {
                    privateKeyFile.Close();
                }
            }


        }
    }
}