Hello

I don't want to argue against another captcha system, I only want to explain where IMHO the pros for math captchas are located.

Humans can always brake the security, ... you can possible block them, but is currently not easy because you can block IP's, but you can not just drop down an list of country's and block them, or just allowed some country... it could one more option, if it's possible to integrate that too. They can use proxys, is true, but proxies have to much problems, and are much slower in most cases... and it's possible to add protection against (known) proxies.

Ok, you can block IP-ranges but I think, that this is not a solution. What, if a good guy from that IP-range wants to post in the forum? But I see, you know this problems.

About mathematical formula, I'm not a programmer my self, but I can imagine if they can brake most of images, they can much easier brake some question asking "What is 1+1?" or "What is 1 + 1?" or "Say to me, 1 more 1 is how much?", they have just to detect where is the numbers an what is the type of calculations.

They have to know where to search. Thatswhy:

... if there is no semantic interconnection (HTML-wise) between the question and the form field for the answer ...

But I know, that's only another type of security by obscurity. And: yes, it is breakable.

Tschö, Auge