I am sorry to report, due to a lack of interest, and an inherent unusability with LCD monitors, the backscatter mod for phpbb3 (the beginning stages of CASPER) are no longer supported.
I am also sorry to report, that due to my work with ZB Block
(my php site protection/anti-spam wrapper) taking all my time, I have not had any time to devote to CASPER (so this project is virtually graveyarded.)
However, as the program was supposed to be GPL, I invite the community here to make a time-based CAPTCHA that was along CASPER's lines. (That being a fairly simple CAPTCHA, obfuscated by a moving blank-spot to avoid screen grabs working with OCR). Perhaps it would have been a shockwave-flash that would also have detected if it was being framed by a fraudulent solver scheme.
For those of you who would wish to use an eaiser to solve captcha (such as the one provided with phpBB), but still have fairly good protection, please give ZB Block
P.S. I would enter ZB Block as a mod on this site, except for the fact it works with any php script, and is neither phpBB specific, nor installable as a classic mod.(requires an edit of common.php to make it work)