As the name suggests, it's what par is for (see also PAR::FAQ). Note also the comment about 100% obfuscation being impossible, or to put it in terms of a conjecture of my own: "to every security measure there exists a loophole and to every loophole there exists a security measure" ;)

Update: to illuminate the term "obfuscation", we talk about obfuscating source code as a geeky hobby - it's a sort of in-group elitism thing and relates to "play" code. The question of obfuscating for distribution is entirely different and uses binary obfuscation - the original source code for serious work should definitely NOT be obfuscated but should of course be maintainable!!

More update: The official (as well as therefore monk-popular) answer to How can we do business with Perl is to license it. But if you trace the discussion first there and then take the link back to 2006 you'll find plenty of points about how really to build a Perl business. My personal idea I plan to use is have a licensing server say http that the product checks in with say on startup to see if its IP address is registered and otherwise fatal error or alternative fatal error for unplugged case: "Fatal error requesting license key from manufacturer site" ;) yes okay it could be hacked but I am really out to stop people copying software internally in a company for free as a genuine mistake without realising that it isn't in the deal to have multiple implementations without permission - horses for courses.