public class Encrypt    {        /// 
        /// MD5加密方法        /// 
        /// 传入一个字符串        /// 
             public static string GetMd5(string str, bool toLower = true)        {            if (String.IsNullOrWhiteSpace(str))            {                Logger.Info("MD5参数空");                return string.Empty;            }            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();            string a = BitConverter.ToString(md5.ComputeHash(Encoding.UTF8.GetBytes(str)));            a = a.Replace("-", "");            return toLower ? a.ToLower() : a;        }        /// 
          /// SHA1 加密，返回大写字符串          /// 
          /// 需要加密字符串          /// 指定加密编码          /// 
     
      返回40位大写字符串
               public static string SHA1(string content, Encoding encode)        {            try            {                SHA1 sha1 = new SHA1CryptoServiceProvider();                byte[] bytes_in = encode.GetBytes(content);                byte[] bytes_out = sha1.ComputeHash(bytes_in);                sha1.Dispose();                string result = BitConverter.ToString(bytes_out);                result = result.Replace("-", "");                return result;            }            catch (Exception ex)            {                throw new Exception("SHA1加密出错：" + ex.Message);            }        }        /// 
        /// des加密        /// 
        /// 需要加密的报文        /// 秘钥        /// 
             public static string DesEncrypt(string datastr, string keystr)        {            DESCryptoServiceProvider desc = new DESCryptoServiceProvider();            byte[] key = System.Text.Encoding.ASCII.GetBytes(keystr);            byte[] data = System.Text.Encoding.Unicode.GetBytes(datastr);            MemoryStream ms = new MemoryStream();            CryptoStream cs = new CryptoStream(ms, desc.CreateEncryptor(key, key), CryptoStreamMode.Write);            cs.Write(data, 0, data.Length);            cs.FlushFinalBlock();            return System.Convert.ToBase64String(ms.ToArray());        }        /// 
        /// 8个bit位，是DES算法的初始化        /// 
        private static readonly byte[] Keys = new byte[] { 0x12, 0x34, 0x56, 120, 0x90, 0xab, 0xcd, 0xef };        /// 
        /// des解密        /// 
        /// 需要解密的报文        /// 秘钥        /// 
             public static string DesDecrypt(string decryptString, string decryptKey)        {            byte[] result = null;            try            {                decryptKey = decryptKey.Length > 8 ? decryptKey.Substring(0, 8) : decryptKey;                decryptKey = decryptKey.PadRight(8, ' ');                byte[] bytes = Encoding.UTF8.GetBytes(decryptKey);                byte[] keys = Keys;                //判断是否是base64的字符串                  if (Regular.IsBase64(decryptString) == false) //转换异常出现位置1,自己处理                      return string.Empty;                byte[] buffer = Convert.FromBase64String(decryptString);                DESCryptoServiceProvider provider = new DESCryptoServiceProvider();                MemoryStream stream = new MemoryStream();                ICryptoTransform tran = provider.CreateDecryptor(bytes, keys);                CryptoStream stream2 = new CryptoStream(stream, tran, CryptoStreamMode.Write);                stream2.Write(buffer, 0, buffer.Length);                // stream2.FlushFinalBlock(); //不处理异常情况                  try                {                    stream2.FlushFinalBlock(); //转换异常出现位置2,使用try/catch 处理                  }                catch                {                    return string.Empty;                }                result = stream.ToArray();                stream.Dispose();                return Encoding.UTF8.GetString(result);            }            catch (Exception ex)            {                Logger.Error(ex.Message);                return string.Empty;            }        }        /// 
        /// Base64加密        /// 
        /// 加密采用的编码方式        /// 待加密的明文        /// 
             public static string Base64Encode(Encoding encodeType, string source)        {            string encode = string.Empty;            byte[] bytes = encodeType.GetBytes(source);            try            {                encode = Convert.ToBase64String(bytes);            }            catch            {                encode = source;            }            return encode;        }        /// 
        /// Base64解密        /// 
        /// 解密采用的编码方式，注意和加密时采用的方式一致        /// 待解密的密文        /// 
     
      解密后的字符串
             public static string Base64Decode(Encoding encodeType, string result)        {            string decode = string.Empty;            byte[] bytes = Convert.FromBase64String(result);            try            {                decode = encodeType.GetString(bytes);            }            catch            {                decode = result;            }            return decode;        }    }