Digg’s Evolving CAPTCHA

Approximately 30 hours after I posted Digg made a change to CAPTCHA by altering the foreground colors and background colors, alternating normal and bold face, and mixing upper an lowercase letters. With the a slight modification to my program (not making all letters lowercase) it reduced my program’s accuracy to 11 % (out of 200 samples). But there was another problem, approximately 15% were not human solvable.
Continue reading