RSA非对称加密封装

namespace AboutLicAuth
{
     public class CryptRSA
     {
         /// <summary>
         /// 对文件进行签名
         /// </summary>
         /// <param name="textToSign">文件</param>
         /// <param name="priKeyFile">保存私钥的文件</param>
         /// <returns>签名</returns>
         public string SignAuth(string infoToSign, string priKeyFile)
         {
             string signKey = null;
             RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
             {
                 //获取密钥
                 string priKey = LoadKeyFromFile(priKeyFile);
                 rsa.FromXmlString(priKey);

                 RSAPKCS1SignatureFormatter rsaFormatter = new RSAPKCS1SignatureFormatter(rsa);
                 rsaFormatter.SetHashAlgorithm("SHA1");
                 byte[] strPlain = ASCIIEncoding.ASCII.GetBytes(infoToSign);

                 SHA1Managed sha = new SHA1Managed();
                 byte[] bytePlain = sha.ComputeHash(strPlain);
                 byte[] byteOfSign = rsaFormatter.CreateSignature(bytePlain);
                 signKey = Convert.ToBase64String(byteOfSign);
                 return signKey;
                 //return byteOfSign;
             }
         }

         /// <summary>
         /// 验证签名是否合法
         /// </summary>
         /// <param name="textToSign">文件</param>
         /// <param name="signKey">签名</param>
         /// <param name="pubKeyFile">保存公钥的文件</param>
         /// <returns>签名是否合法</returns>
         public bool CheckAuth(string strInfo,string signKey, string pubKeyFile)
         {
             RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
             {
                 string pubKey = LoadKeyFromFile(pubKeyFile);
                 rsa.FromXmlString(pubKey);

                 RSAPKCS1SignatureDeformatter rsaDeFormatter = new RSAPKCS1SignatureDeformatter(rsa);
                 rsaDeFormatter.SetHashAlgorithm("SHA1");
                 byte[] byteInfo = ASCIIEncoding.ASCII.GetBytes(strInfo);
                 byte[] byteSignKey = Convert.FromBase64String(signKey);
                 SHA1Managed sha = new SHA1Managed();

                 byte[] byteHash = sha.ComputeHash(byteInfo);
                 bool isMatch = rsaDeFormatter.VerifySignature(byteHash,byteSignKey);
                 return isMatch;
             }
         }

         //从文件中读出信息
         protected string LoadKeyFromFile(string fileName)
         {
             StreamReader sr = new StreamReader(fileName);
             string key = sr.ReadToEnd();
             sr.Close();
             return key;
         }

     }

     /// <summary>
     /// 产生工私钥文件
     /// </summary>
     public class GenarateRsaKey
     {
         /// <summary>
         /// 产生公私钥对
         /// </summary>
         public static void GenKey()
         {
             string keyPairs=null;
             string pubKey=null;
             RSACryptoServiceProvider rsaprd = new RSACryptoServiceProvider();
             keyPairs = rsaprd.ToXmlString(true);
             pubKey = rsaprd.ToXmlString(false);
             SaveKeyToFile("key.xml", keyPairs);
             SaveKeyToFile("pubKey.xml", pubKey);
         }

         protected static void SaveKeyToFile(string fileName, string data)
         {
             StreamWriter sw = new StreamWriter(fileName);
             sw.Write(data);
             sw.Close();
         }