DES(Data Encryption Standard)数据加密标准

DES算法入口参数

    DES算法的入口参数有三个:Key、Data、Mode。其中Key为7个字节共56位，是DES算法的工作密钥。Data为8个字节64位，是要被加密或解密的数据;Mode为DES的工作方法,有两种:加密或解密。

1. 加密解密文件

           /// <summary>
           /// Enctypt File
           /// </summary>
           /// <param name="sInputFilename"></param>
           /// <param name="sOutputFilename"></param>
           /// <param name="sKey"></param>
           public void EncryptFile(string sInputFilename, string sOutputFilename, string sKey)
           {
               DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
               //A 64 bit key and IV is required for this provider.
               //Set secret key For DES algorithm.
               DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
               //Set initialization vector.
               DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   
               FileStream fin = null;
               FileStream fout = null;
               CryptoStream cryptoStream = null;
               try
               {
                   fin = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
                   fout = new FileStream(sOutputFilename, FileMode.OpenOrCreate, FileAccess.Write);
                   cryptoStream = new CryptoStream(fout, DES.CreateEncryptor(), CryptoStreamMode.Write);
   
                   byte[] bin = new byte[100];  //This is intermediate storage for the decryption.
                   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.
   
                   //Read from the input file, then encrypt and write to the output file.
                   while (rdlen < totlen)
                   {
                       len = fin.Read(bin, 0, 100);
                       cryptoStream.Write(bin, 0, len);
                       rdlen = rdlen + len;
                   }
               }
               catch (Exception ex)
               {
                   throw ex;
               }
               finally
               {
                   if (cryptoStream != null) { cryptoStream.Close(); }
                   if (fout != null) { fout.Close(); }
                   if (fin != null) { fin.Close(); }
               }
           }
   
           /// <summary>
           /// Decrypt File
           /// </summary>
           /// <param name="sInputFilename"></param>
           /// <param name="sOutputFilename"></param>
           /// <param name="sKey"></param>
           public void DecryptFile(string sInputFilename, string sOutputFilename,string sKey)
           {
               DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
               //A 64 bit key and IV is required for this provider.
               //Set secret key For DES algorithm.
               DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
               //Set initialization vector.
               DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   
               FileStream fin = null;
               FileStream fout = null;
               CryptoStream cryptoStream = null;
               try
               {
                   fin = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
                   fout = new FileStream(sOutputFilename, FileMode.OpenOrCreate, FileAccess.Write);
                   cryptoStream = new CryptoStream(fin, DES.CreateDecryptor(), CryptoStreamMode.Read);
                 
                   byte[] bin = new byte[100];  //This is intermediate storage for the decryption.
                   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.
   
                   //Read from the input file, then encrypt and write to the output file.
                   while (rdlen < totlen)
                   {
                       len = cryptoStream.Read(bin, 0, 100);
                       if (len == 0) { break; }
                       fout.Write(bin, 0, len);
                       rdlen = rdlen + len;
                   }
               }
               catch(Exception ex)
               {
                   throw ex;
               }
               finally
               {
                   if (cryptoStream != null) { cryptoStream.Close(); }
                   if (fout != null) { fout.Close(); }
                   if (fin != null) { fin.Close(); }
               }
           }

2. 加密解密文本

           /// <summary>
           /// Encrypt Text
           /// </summary>
           public string DesEncrypt(string pToEncrypt, string sKey)
           {
               MemoryStream ms = null;
               CryptoStream ctyptoStream = null;
               try
               {
                   DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                   des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
                   des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   
                   byte[] inputByteArray = Encoding.ASCII.GetBytes(pToEncrypt);
                 
                   ms = new System.IO.MemoryStream();
                   ctyptoStream = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
                   ctyptoStream.Write(inputByteArray, 0, inputByteArray.Length);
                   ctyptoStream.FlushFinalBlock();
               }
               catch (Exception ex)
               {
                   throw ex;
               }
               finally
               {
                   if (ctyptoStream != null) { ctyptoStream.Close(); }
                   if (ms != null) { ms.Close(); }
               }
               return Convert.ToBase64String(ms.ToArray());
           }
   
           /// <summary>
           /// Dectypt Text
           /// </summary>
           public string DesDecrypt(string pToDecrypt, string sKey)
           {
               MemoryStream ms = null;
               CryptoStream ctyptoStream = null;
               try
               {
                   DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                   des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
                   des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   
                   byte[] inputByteArray = Convert.FromBase64String(pToDecrypt);
   
                   ms = new System.IO.MemoryStream();
                   ctyptoStream = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
                   ctyptoStream.Write(inputByteArray, 0, inputByteArray.Length);
                   ctyptoStream.FlushFinalBlock();
               }
               catch (Exception ex)
               {
                   throw ex;
               }
               finally
               {
                   if (ctyptoStream != null) { ctyptoStream.Close(); }
                   if (ms != null) { ms.Close(); }
               }
               return Encoding.ASCII.GetString(ms.ToArray());
           }