Purpose of captcha system?

[zhaoq]

Hi,

I think having a captcha for submitting a problem is kind of annoying and a bit redundant -- didn't you already have a wait time of 30 seconds after submitting an answer because some guy tried to brute-force solutions last year or something? Yea I thought the 30 second delay fixed that.

What's the purpose of having the captcha?

[rayfil]

Primarily to twart the use of autosubmitters. Someone had posted a script to enter a list of answers.

[jkastelic]

Hi

Although I think that these captchas are somewhat annoying, I suggest to the admins of the site to use reCAPTCHA. This is a free replacement for common captchas. The idea of reCAPTCHA is that while you are proving you are human, you also help to digitise old books (that OCR can't recognize). You can read more on

http://recaptcha.net/learnmore.html

There is also a demostration of the free product.

[bucko]

Incidentally, the cache time on the codes is very, very short. Every time I wish to submit I must remember to refresh because otherwise I get an invalid captcha error. It can't be so hard to store the things for a day or two (or at least 12 hours) per-problem and per-user, can it? Some of us load the problem, have lunch, work stuff out on paper, do other stuff, then come back and finish a solution, and it's somewhat frustrating that we must enter it twice!

[elendiastarman]

Incidentally, the cache time on the codes is very, very short. Every time I wish to submit I must remember to refresh because otherwise I get an invalid captcha error. It can't be so hard to store the things for a day or two (or at least 12 hours) per-problem and per-user, can it? Some of us load the problem, have lunch, work stuff out on paper, do other stuff, then come back and finish a solution, and it's somewhat frustrating that we must enter it twice!

Just click on the captcha. It refreshes only the captcha and you only have to enter your answer once. As for remembering to click it, I can't help you there; I learned very quickly to always click the captcha right before I submit a solution.

[bucko]

Perhaps it could be made more clear: I would suggest actually hiding the solution area until the user clicks a button of some sort (of course, for a non-JS browser it must be shown. One could put it in a CSS-hidden DIV and make the image refresh at the same time as making the DIV visible.

Or perhaps make the JS somehow indicate that the captcha is out of date and will need refreshing.

It should be possible to do either of these things remarkably easily.

[Lord_Farin]

Perhaps it could be made more clear: I would suggest actually hiding the solution area until the user clicks a button of some sort (of course, for a non-JS browser it must be shown. One could put it in a CSS-hidden DIV and make the image refresh at the same time as making the DIV visible.

Or perhaps make the JS somehow indicate that the captcha is out of date and will need refreshing.

It should be possible to do either of these things remarkably easily.

I like this idea. It solves the issues and is very neat. It could also be as simple as to initially disable the solution area text forms and make the captcha refresh when those are clicked

[TripleM]

Perhaps it could be made more clear: I would suggest actually hiding the solution area until the user clicks a button of some sort (of course, for a non-JS browser it must be shown. One could put it in a CSS-hidden DIV and make the image refresh at the same time as making the DIV visible.

I agree I often have to refresh before submitting, but you definitely wouldn't want to do that. If the aim is to make submitting faster, you don't want to force everyone to click an extra time.