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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2. 加密解密文本
   

    1         /// <summary>
   
    2         /// Encrypt Text
   
    3         /// </summary>
   
    4         public string DesEncrypt(string pToEncrypt, string sKey)
   
    5         {
   
    6             MemoryStream ms = null;
   
    7             CryptoStream ctyptoStream = null;
   
    8             try
   
    9             {
   
   10                 DESCryptoServiceProvider des = new DESCryptoServiceProvider();
   
   11                 des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
   
   12                 des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   
   13 
   
   14                 byte[] inputByteArray = Encoding.ASCII.GetBytes(pToEncrypt);
   
   15               
   
   16                 ms = new System.IO.MemoryStream();
   
   17                 ctyptoStream = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
   
   18                 ctyptoStream.Write(inputByteArray, 0, inputByteArray.Length);
   
   19                 ctyptoStream.FlushFinalBlock();
   
   20             }
   
   21             catch (Exception ex)
   
   22             {
   
   23                 throw ex;
   
   24             }
   
   25             finally
   
   26             {
   
   27                 if (ctyptoStream != null) { ctyptoStream.Close(); }
   
   28                 if (ms != null) { ms.Close(); }
   
   29             }
   
   30             return Convert.ToBase64String(ms.ToArray());
   
   31         }
   
   32 
   
   33         /// <summary>
   
   34         /// Dectypt Text
   
   35         /// </summary>
   
   36         public string DesDecrypt(string pToDecrypt, string sKey)
   
   37         {
   
   38             MemoryStream ms = null;
   
   39             CryptoStream ctyptoStream = null;
   
   40             try
   
   41             {
   
   42                 DESCryptoServiceProvider des = new DESCryptoServiceProvider();
   
   43                 des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
   
   44                 des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
   
   45 
   
   46                 byte[] inputByteArray = Convert.FromBase64String(pToDecrypt);
   
   47 
   
   48                 ms = new System.IO.MemoryStream();
   
   49                 ctyptoStream = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
   
   50                 ctyptoStream.Write(inputByteArray, 0, inputByteArray.Length);
   
   51                 ctyptoStream.FlushFinalBlock();
   
   52             }
   
   53             catch (Exception ex)
   
   54             {
   
   55                 throw ex;
   
   56             }
   
   57             finally
   
   58             {
   
   59                 if (ctyptoStream != null) { ctyptoStream.Close(); }
   
   60                 if (ms != null) { ms.Close(); }
   
   61             }
   
   62             return Encoding.ASCII.GetString(ms.ToArray());
   
   63         }

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