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

    1         /// <summary>
    2         /// Enctypt File
    3         /// </summary>
    4         /// <param name="sInputFilename"></param>
    5         /// <param name="sOutputFilename"></param>
    6         /// <param name="sKey"></param>
    7         public void EncryptFile(string sInputFilename, string sOutputFilename, string sKey)
    8         {
    9             DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
   10             //A 64 bit key and IV is required for this provider.
   11             //Set secret key For DES algorithm.
   12             DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
   13             //Set initialization vector.
   14             DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   15 
   16             FileStream fin = null;
   17             FileStream fout = null;
   18             CryptoStream cryptoStream = null;
   19             try
   20             {
   21                 fin = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
   22                 fout = new FileStream(sOutputFilename, FileMode.OpenOrCreate, FileAccess.Write);
   23                 cryptoStream = new CryptoStream(fout, DES.CreateEncryptor(), CryptoStreamMode.Write);
   24 
   25                 byte[] bin = new byte[100];  //This is intermediate storage for the decryption.
   26                 long rdlen = 0;              //This is the total number of bytes written.
   27                 long totlen = fin.Length;    //This is the total length of the input file.
   28                 int len;                     //This is the number of bytes to be written at a time.
   29 
   30                 //Read from the input file, then encrypt and write to the output file.
   31                 while (rdlen < totlen)
   32                 {
   33                     len = fin.Read(bin, 0, 100);
   34                     cryptoStream.Write(bin, 0, len);
   35                     rdlen = rdlen + len;
   36                 }
   37             }
   38             catch (Exception ex)
   39             {
   40                 throw ex;
   41             }
   42             finally
   43             {
   44                 if (cryptoStream != null) { cryptoStream.Close(); }
   45                 if (fout != null) { fout.Close(); }
   46                 if (fin != null) { fin.Close(); }
   47             }
   48         }
   49 
   50         /// <summary>
   51         /// Decrypt File
   52         /// </summary>
   53         /// <param name="sInputFilename"></param>
   54         /// <param name="sOutputFilename"></param>
   55         /// <param name="sKey"></param>
   56         public void DecryptFile(string sInputFilename, string sOutputFilename,string sKey)
   57         {
   58             DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
   59             //A 64 bit key and IV is required for this provider.
   60             //Set secret key For DES algorithm.
   61             DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
   62             //Set initialization vector.
   63             DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   64 
   65             FileStream fin = null;
   66             FileStream fout = null;
   67             CryptoStream cryptoStream = null;
   68             try
   69             {
   70                 fin = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
   71                 fout = new FileStream(sOutputFilename, FileMode.OpenOrCreate, FileAccess.Write);
   72                 cryptoStream = new CryptoStream(fin, DES.CreateDecryptor(), CryptoStreamMode.Read);
   73               
   74                 byte[] bin = new byte[100];  //This is intermediate storage for the decryption.
   75                 long rdlen = 0;              //This is the total number of bytes written.
   76                 long totlen = fin.Length;    //This is the total length of the input file.
   77                 int len;                     //This is the number of bytes to be written at a time.
   78 
   79                 //Read from the input file, then encrypt and write to the output file.
   80                 while (rdlen < totlen)
   81                 {
   82                     len = cryptoStream.Read(bin, 0, 100);
   83                     if (len == 0) { break; }
   84                     fout.Write(bin, 0, len);
   85                     rdlen = rdlen + len;
   86                 }
   87             }
   88             catch(Exception ex)
   89             {
   90                 throw ex;
   91             }
   92             finally
   93             {
   94                 if (cryptoStream != null) { cryptoStream.Close(); }
   95                 if (fout != null) { fout.Close(); }
   96                 if (fin != null) { fin.Close(); }
   97             }
   98         }

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