About PEAR::Auth() and cookies

Hi all, As an OOP exercise, i'd like to work on PEAR::Auth() and implementing a Cookie based auth support. I know that cookie based Auth is not recommended for evident security issues, but i think it can be a really cool feature for websites where security is no big deal. for thoses sites, i plan to store plain login and pass datas as md5 hashe. I've seen that in LiveUser, the cookie based auth use only the loginname. But i'd prefer add the password hash. To your minds ;), what should be the proper way ? modifying the class itself or creating a new class which extends Auth ? I'd like to implement it only for file and DB containers (adding that to other containers definitly doesn't make sense) , in the same way , should i modify or extend them ? Regards -- Xavier