using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication2
{
    class RSACryption
    {
        static void Main(string[] args)
        {
            //產生一對公鑰，私鑰
            RSACryptoServiceProvider rsa = new
 
 RSACryptoServiceProvider();
            string xmlKeys = rsa.ToXmlString(true);   //私鑰
            string xmlPublicKey = rsa.ToXmlString(false);   //公鑰

            string EncryptString = RSAEncrypt(xmlPublicKey, "1223345611");

            Console.WriteLine(EncryptString);
            Console.WriteLine("------------------------------------"
 
);

            string DecryptString = RSADecrypt(xmlKeys, EncryptString);
            Console.WriteLine(DecryptString);
            Console.ReadKey();

        }

        /// <summary>
        /// RSA的加密函式
        /// </summary>
        /// <param name="xmlPublicKey">公鑰</param>
        /// <param name="encryptString">
 
待加密的字串</param>
        /// <returns></returns>
        public static string RSAEncrypt(string xmlPublicKey, string encryptString)
        {
            try
            {
                byte[] PlainTextBArray;
                byte[] CypherTextBArray;
                string Result;
                RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
                rsa.FromXmlString(xmlPublicKey);
                PlainTextBArray = (new UnicodeEncoding()).GetBytes(encryptString);
                CypherTextBArray = rsa.Encrypt(PlainTextBArray, false);
                Result = Convert.ToBase64String(CypherTextBArray);
                return Result;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        /// <summary>
        /// RSA的解密函式
        /// </summary>
        /// <param name="xmlPrivateKey">私鑰</param>
        /// <param name="decryptString">待解密的字串</param>
        /// <returns></returns>
        public static string RSADecrypt(string xmlPrivateKey, string decryptString)
        {
            try
            {
                byte[] PlainTextBArray;
                byte[] DypherTextBArray;
                string Result;
                System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
                rsa.FromXmlString(xmlPrivateKey);
                PlainTextBArray = Convert.FromBase64String(decryptString);
                DypherTextBArray = rsa.Decrypt(PlainTextBArray, false);
                Result = (new UnicodeEncoding()).GetString(DypherTextBArray);
                return Result;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
    }
}