<pre class="brush:c#; toolbar: true; auto-links: false;">方法一：  //须添加对System.Web的引用   using System.Web.Security;     ...     /// <summary>   /// SHA1加密字符串   /// </summary>   /// <param name="source">源字符串</param>   /// <returns>加密后的字符串</returns>   public string SHA1(string source)   {       return FormsAuthentication.HashPasswordForStoringInConfigFile(source, "SHA1");   }     /// <summary>   /// MD5加密字符串   /// </summary>   /// <param name="source">源字符串</param>   /// <returns>加密后的字符串</returns>   public string MD5(string source)   {       return FormsAuthentication.HashPasswordForStoringInConfigFile(source, "MD5");;   } </pre>    <pre class="brush:c#; toolbar: true; auto-links: false;">方法二(可逆加密解密)：  using System.Security.Cryptography;     ...     public string Encode(string data)   {       byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);       byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);         DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();       int i = cryptoProvider.KeySize;       MemoryStream ms = new MemoryStream();       CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);         StreamWriter sw = new StreamWriter(cst);       sw.Write(data);       sw.Flush();       cst.FlushFinalBlock();       sw.Flush();       return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);     }     public string Decode(string data)   {       byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);       byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);         byte[] byEnc;       try       {           byEnc = Convert.FromBase64String(data);       }       catch       {           return null;       }         DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();       MemoryStream ms = new MemoryStream(byEnc);       CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);       StreamReader sr = new StreamReader(cst);       return sr.ReadToEnd();   } </pre>    <pre class="brush:c#; toolbar: true; auto-links: false;">方法三(MD5不可逆)：  using System.Security.Cryptography;     ...     //MD5不可逆加密     //32位加密     public string GetMD5_32(string s, string _input_charset)   {       MD5 md5 = new MD5CryptoServiceProvider();       byte[] t = md5.ComputeHash(Encoding.GetEncoding(_input_charset).GetBytes(s));       StringBuilder sb = new StringBuilder(32);       for (int i = 0; i < t.Length; i++)       {           sb.Append(t[i].ToString("x").PadLeft(2, '0'));       }       return sb.ToString();   }     //16位加密   public static string GetMd5_16(string ConvertString)   {       MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();       string t2 = BitConverter.ToString(md5.ComputeHash(UTF8Encoding.Default.GetBytes(ConvertString)), 4, 8);       t2 = t2.Replace("-", "");       return t2;   } </pre>    <pre class="brush:c#; toolbar: true; auto-links: false;">方法四(对称加密)：  using System.IO;   using System.Security.Cryptography;     ...     private SymmetricAlgorithm mobjCryptoService;   private string Key;   /// <summary>      /// 对称加密类的构造函数      /// </summary>      public SymmetricMethod()   {       mobjCryptoService = new RijndaelManaged();       Key = "Guz(%&hj7x89H$yuBI0456FtmaT5&fvHUFCy76*h%(HilJ$lhj!y6&(*jkP87jH7";   }   /// <summary>      /// 获得密钥      /// </summary>      /// <returns>密钥</returns>      private byte[] GetLegalKey()   {       string sTemp = Key;       mobjCryptoService.GenerateKey();       byte[] bytTemp = mobjCryptoService.Key;       int KeyLength = bytTemp.Length;       if (sTemp.Length > KeyLength)           sTemp = sTemp.Substring(0, KeyLength);       else if (sTemp.Length < KeyLength)           sTemp = sTemp.PadRight(KeyLength, ' ');       return ASCIIEncoding.ASCII.GetBytes(sTemp);   }   /// <summary>      /// 获得初始向量IV      /// </summary>      /// <returns>初试向量IV</returns>      private byte[] GetLegalIV()   {       string sTemp = "E4ghj*Ghg7!rNIfb&95GUY86GfghUb#er57HBh(u%g6HJ($jhWk7&!hg4ui%$hjk";       mobjCryptoService.GenerateIV();       byte[] bytTemp = mobjCryptoService.IV;       int IVLength = bytTemp.Length;       if (sTemp.Length > IVLength)           sTemp = sTemp.Substring(0, IVLength);       else if (sTemp.Length < IVLength)           sTemp = sTemp.PadRight(IVLength, ' ');       return ASCIIEncoding.ASCII.GetBytes(sTemp);   }   /// <summary>      /// 加密方法      /// </summary>      /// <param name="Source">待加密的串</param>      /// <returns>经过加密的串</returns>      public string Encrypto(string Source)   {       byte[] bytIn = UTF8Encoding.UTF8.GetBytes(Source);       MemoryStream ms = new MemoryStream();       mobjCryptoService.Key = GetLegalKey();       mobjCryptoService.IV = GetLegalIV();       ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor();       CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);       cs.Write(bytIn, 0, bytIn.Length);       cs.FlushFinalBlock();       ms.Close();       byte[] bytOut = ms.ToArray();       return Convert.ToBase64String(bytOut);   }   /// <summary>      /// 解密方法      /// </summary>      /// <param name="Source">待解密的串</param>      /// <returns>经过解密的串</returns>      public string Decrypto(string Source)   {       byte[] bytIn = Convert.FromBase64String(Source);       MemoryStream ms = new MemoryStream(bytIn, 0, bytIn.Length);       mobjCryptoService.Key = GetLegalKey();       mobjCryptoService.IV = GetLegalIV();       ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor();       CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);       StreamReader sr = new StreamReader(cs);       return sr.ReadToEnd();   } </pre>    <pre class="brush:c#; toolbar: true; auto-links: false;">方法五：  using System.IO;   using System.Security.Cryptography;   using System.Text;     ...     //默认密钥向量   private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };   /// <summary>   /// DES加密字符串   /// </summary>   /// <param name="encryptString">待加密的字符串</param>   /// <param name="encryptKey">加密密钥,要求为8位</param>   /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>   public static string EncryptDES(string encryptString, string encryptKey)   {       try       {           byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));           byte[] rgbIV = Keys;           byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);           DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();           MemoryStream mStream = new MemoryStream();           CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);           cStream.Write(inputByteArray, 0, inputByteArray.Length);           cStream.FlushFinalBlock();           return Convert.ToBase64String(mStream.ToArray());       }       catch       {           return encryptString;       }   }     /// <summary>   /// DES解密字符串   /// </summary>   /// <param name="decryptString">待解密的字符串</param>   /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>   /// <returns>解密成功返回解密后的字符串，失败返源串</returns>   public static string DecryptDES(string decryptString, string decryptKey)   {       try       {           byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);           byte[] rgbIV = Keys;           byte[] inputByteArray = Convert.FromBase64String(decryptString);           DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();           MemoryStream mStream = new MemoryStream();           CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);           cStream.Write(inputByteArray, 0, inputByteArray.Length);           cStream.FlushFinalBlock();           return Encoding.UTF8.GetString(mStream.ToArray());       }       catch       {           return decryptString;       }   }  </pre>    <pre class="brush:c#; toolbar: true; auto-links: false;">方法六(文件加密)：  using System.IO;   using System.Security.Cryptography;   using System.Text;     ...     //加密文件   private static void EncryptData(String inName, String outName, byte[] desKey, byte[] desIV)   {       //Create the file streams to handle the input and output files.       FileStream fin = new FileStream(inName, FileMode.Open, FileAccess.Read);       FileStream fout = new FileStream(outName, FileMode.OpenOrCreate, FileAccess.Write);       fout.SetLength(0);         //Create variables to help with read and write.       byte[] bin = new byte[100]; //This is intermediate storage for the encryption.       long rdlen = 0;              //This is the total number of bytes written.       long totlen = fin.Length;    //This is the total length of the input file.       int len;                     //This is the number of bytes to be written at a time.         DES des = new DESCryptoServiceProvider();       CryptoStream encStream = new CryptoStream(fout, des.CreateEncryptor(desKey, desIV), CryptoStreamMode.Write);         //Read from the input file, then encrypt and write to the output file.       while (rdlen < totlen)       {           len = fin.Read(bin, 0, 100);           encStream.Write(bin, 0, len);           rdlen = rdlen + len;       }         encStream.Close();       fout.Close();       fin.Close();   }     //解密文件   private static void DecryptData(String inName, String outName, byte[] desKey, byte[] desIV)   {       //Create the file streams to handle the input and output files.       FileStream fin = new FileStream(inName, FileMode.Open, FileAccess.Read);       FileStream fout = new FileStream(outName, FileMode.OpenOrCreate, FileAccess.Write);       fout.SetLength(0);         //Create variables to help with read and write.       byte[] bin = new byte[100]; //This is intermediate storage for the encryption.       long rdlen = 0;              //This is the total number of bytes written.       long totlen = fin.Length;    //This is the total length of the input file.       int len;                     //This is the number of bytes to be written at a time.         DES des = new DESCryptoServiceProvider();       CryptoStream encStream = new CryptoStream(fout, des.CreateDecryptor(desKey, desIV), CryptoStreamMode.Write);         //Read from the input file, then encrypt and write to the output file.       while (rdlen < totlen)       {           len = fin.Read(bin, 0, 100);           encStream.Write(bin, 0, len);           rdlen = rdlen + len;       }         encStream.Close();       fout.Close();       fin.Close();   }</pre>    <p> </p>    <p></p>    <pre class="brush:c#; toolbar: true; auto-links: false;">using System; using System.Security.Cryptography;//这个是处理文字编码的前提 using System.Text; using System.IO; /// <summary> /// DES加密方法 /// </summary> /// <param name="strPlain">明文</param> /// <param name="strDESKey">密钥</param> /// <param name="strDESIV">向量</param> /// <returns>密文</returns> public string DESEncrypt(string strPlain,string strDESKey,string strDESIV) {  //把密钥转换成字节数组  byte[] bytesDESKey=ASCIIEncoding.ASCII.GetBytes(strDESKey);  //把向量转换成字节数组  byte[] bytesDESIV=ASCIIEncoding.ASCII.GetBytes(strDESIV);  //声明1个新的DES对象  DESCryptoServiceProvider desEncrypt=new DESCryptoServiceProvider();  //开辟一块内存流  MemoryStream msEncrypt=new MemoryStream();  //把内存流对象包装成加密流对象  CryptoStream csEncrypt=new CryptoStream(msEncrypt,desEncrypt.CreateEncryptor(bytesDESKey,bytesDESIV),CryptoStreamMode.Write);  //把加密流对象包装成写入流对象  StreamWriter swEncrypt=new StreamWriter(csEncrypt);  //写入流对象写入明文  swEncrypt.WriteLine(strPlain);  //写入流关闭  swEncrypt.Close();  //加密流关闭  csEncrypt.Close();  //把内存流转换成字节数组，内存流现在已经是密文了  byte[] bytesCipher=msEncrypt.ToArray();  //内存流关闭  msEncrypt.Close();  //把密文字节数组转换为字符串，并返回  return UnicodeEncoding.Unicode.GetString(bytesCipher); }     /// <summary> /// DES解密方法 /// </summary> /// <param name="strCipher">密文</param> /// <param name="strDESKey">密钥</param> /// <param name="strDESIV">向量</param> /// <returns>明文</returns> public string DESDecrypt(string strCipher,string strDESKey,string strDESIV) {  //把密钥转换成字节数组  byte[] bytesDESKey=ASCIIEncoding.ASCII.GetBytes(strDESKey);  //把向量转换成字节数组  byte[] bytesDESIV=ASCIIEncoding.ASCII.GetBytes(strDESIV);  //把密文转换成字节数组  byte[] bytesCipher=UnicodeEncoding.Unicode.GetBytes(strCipher);  //声明1个新的DES对象  DESCryptoServiceProvider desDecrypt=new DESCryptoServiceProvider();  //开辟一块内存流，并存放密文字节数组  MemoryStream msDecrypt=new MemoryStream(bytesCipher);  //把内存流对象包装成解密流对象  CryptoStream csDecrypt=new CryptoStream(msDecrypt,desDecrypt.CreateDecryptor(bytesDESKey,bytesDESIV),CryptoStreamMode.Read);  //把解密流对象包装成读出流对象  StreamReader srDecrypt=new StreamReader(csDecrypt);  //明文=读出流的读出内容  string strPlainText=srDecrypt.ReadLine();  //读出流关闭  srDecrypt.Close();  //解密流关闭  csDecrypt.Close();  //内存流关闭  msDecrypt.Close();  //返回明文  return strPlainText; }</pre>    <br />    <br />    <p></p>