It sounds like you're planning to do data munging in Perl and then export that data to MySQL in a format that is supported by an existing auth module in C. If you are running mod_perl, you might want to consider using one of the auth modules in Perl, since they'll be easier for you to hack to fit your own needs. There's a list of them here. Of course, you will need to learn how to work with mod_perl for this, and that might be more than you want to deal with right now.