Investigation and Management System-(2) basic process and implementation of MD5 Encryption

The basic process of MD5 encryption:

1. encode a string into a byte array byte [] bytes through the getbytes () method;

2. After the bytes array is encrypted by the MD5 algorithm, a new 16-byte array md5bytes is obtained;

3. Convert the md5bytes array to a string for saving (generally, this process is to convert the encrypted md5bytes to the hexadecimal [0 ~ F] The saved 32-Bit String)

Specific implementation:

 1   Package  Com. atguigu. surveypark. util;  2   Import Java. Security. messagedigest;  3   Public   Class  Datautil {  4       /**  5   * Use the MD5 Algorithm for encryption  6        */  7       Public   Static  String MD5 (string SRC ){  8           Try {  9 Stringbuffer buffer = New  Stringbuffer ();  10               Char [] Chars = {'0', '1', '2', '3', '4', '5', '6', '7 ', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };  11               Byte [] Bytes = SRC. getbytes ();  12 Messagedigest MD = messagedigest. getinstance ("MD5" );  13              Byte [] Targ = Md. Digest (bytes );  14               For ( Byte  B: targ ){  15 Buffer. append (chars [(B> 4) & 0x0f ]);// The Current byte moves four digits to the right and then performs the "and operation" with (0x00001111), that is, the operation on the top four digits.  16 Buffer. append (chars [B & 0x0f ]);// Perform and operate the lower four bits.  17   } 18               Return  Buffer. tostring ();  19 } Catch  (Exception e ){  20   E. printstacktrace ();  21   }  22           Return   Null  ;  23   } 24 }

In addition to converting encrypted byte arrays, you can also directly useCommons-codec.jarThe method provided by the package to encrypt the string.

For example, string md5digest = digestutils. md5hex ("12345 ");

For commons-codec.jar package reference: http://www.cnblogs.com/tingzi/archive/2012/08/17/2643742.html (Commons codec jar package details)

 

Investigation and Management System-(2) basic process and implementation of MD5 Encryption