/// <summary>

         /// RSA加密

         /// </summary>

         /// <param name="strPublickey"></param>

         /// <param name="content"></param>

         /// <returns></returns>

         public string RsaEncrypt(string strPublickey, string content)

         {

             var rsa = new RSACryptoServiceProvider();

             var param = new RSAParameters();

             byte[] bdata = GetBytes("");

             param.Exponent = bdata;

             param.Modulus = GetBytes(strPublickey);

             rsa.ImportParameters(param);

             byte[] cipherbytes = rsa.Encrypt(Encoding.UTF8.GetBytes(content),false);

             return BitConverter.ToString(cipherbytes).Replace("-", string.Empty);

         }

         public byte[] GetBytes(String num)

         {

             BigInteger n = new BigInteger(num, );

             String s = n.ToString();

             if (s.Length %  > )

             {

                 s = new String('',  - s.Length % ) + s;

             }

             byte[] data = new byte[s.Length / ];

             String ocetstr;

             for (int i = ; i < data.Length; i++)

             {

                 ocetstr = s.Substring( * i, );

                 data[i] = Convert.ToByte(ocetstr, );

             }

             return data;

         }
　　　　　　 调用方式
　　　　　　 var result = new BigInteger(pubkey, 16);
           String sp = RsaEncrypt(string.Format("{0}", result), message);

　　　　　　 BigInteger下载地址
　　　　　　 http://www.codeproject.com/Articles/2728/C-BigInteger-Class