http://www.perlmonks.org?node_id=604268


in reply to howto: Perl CGI, image with random scewed text for account creations

I have no experience with it and it looks like it would likely take more heavy lifting to get working, but Authen::PluggableCpatcha provides both standard scrambled text captchas as well as audio output. Fortunately, the module comes with a decent looking tutorial.