After getting bombed with some comment spam yesterday (over 15 of them in various blog entries), I decided I wanted some extra security, but I didn't want to have to approve every comment (especially when the majority of them were spam). So I thought I'd dig into some PHP again and design my own Captcha.
This little project proved to be more challenging than I thought it would be, the easiest part was generating the unique and random image every time, the hardest part was figuring out how to make sure the image was not reused again (even if the user clicks the "Back" button on his browser). While I won't get into the details right here and now, suffice to say that it works completely now and I can now work on making the image even more difficult for a computer to read in the future...if anyone wants it let me know (leave a comment, heh) and I'll post a subsequent entry about some of the details and put the source up.
Anyway, I hope it's not too annoying to those who wish to leave comments...