Creating an md5 signature

 
<?php
    $mystring = "mystring";
    $signature = md5($mystring);
    echo $signature;
?>

1.	Checking for session hijacking
2.	string md5 ( string str [, bool raw_output] )
3.	string md5 ( string str [, bool raw_output] ) produces a data checksum in exactly the same way as sha1( );
4.	PHP's basic md5() function
5.	The protect() MD5 Form Fingerprint Generator
6.	md5.php
7.	Insert a unique ID into a form

Creating an md5 signature : md5 « Utility Function « PHP