Description
string 
md5 ( string str [, bool raw_output] )
     Calculates the MD5 hash of str using the
     RSA Data Security, Inc. 
     MD5 Message-Digest Algorithm, and returns that hash.
     The hash is a 32-character hexadecimal number.  If the optional
     raw_output is set to TRUE, then the md5 digest
     is instead returned in raw binary format with a length of 16.
    
Note: 
      The optional raw_output parameter was added in
      PHP 5.0.0 and defaults to FALSE
     
     
| Example 1. A md5() example | 
<?php$str = 'apple';
 
 if (md5($str) === '1f3870be274f6c49b3e31a0c6728957f') {
 echo "Would you like a green or red apple?";
 exit;
 }
 ?>
 | 
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     See also crc32(), md5_file(), 
     and sha1().