Live data from Hacker News

Chess CAPTCHA

en.lichess.org

61–70 of 171 posts

Re: Chess CAPTCHA

#61
This is very easy to crack due the 2D board, which is trivial to "OCR".

Now the concept is interesting: one could probably do the same in 3D (with random camera angles -- up to a limit) and then it would prove more problematic for AI because one would then need to be able to correctly pieces in 3D and their position on the board.

Re: Chess CAPTCHA

#62
post #45

I am fairly certain it would be quicker to program a computer that can brute force a checkmate in one than I can solve these things by hand. You have what, 11 pieces, they can move into 64 positions each (at most, much less in reality). That means a computer must brute force 64*11 = 704 attempts. In other words, no time at all to bruteforce this once you've read the grid. Reading the grid in itself is rather trivial…

Yes, an afternoon of coding to be able to post spam on exactly one website. Until they change the captcha.

Re: Chess CAPTCHA

#63
post #28

Earlier quoted context omitted.

But serious spammers would prefer to spend this time writing a bot capable of spamming all forums based on some widely used engine. Cracking this captcha won't give you access to any significant audience.

by this argument, the captcha would become useless as soon as it saw widespread adoption. The idea of a captcha is to be strong against bots even if it was directly targeted by spammers.

Yes, it would. But this one will never see wide adoption so it's sufficient.

If every forum had a completely different captcha system, forum spam would pretty much die out.

Re: Chess CAPTCHA

#64
post #52

As I expected most of the HN comments are criticizing it for one reason or another but I like this just because solving simple chess puzzles is FUN which is not true for the tasks in the typical CAPTCHA. Yes, there could be a concern over a spammer automating the process but that might be more hassle than it's worth just to spam an small chess forum.

'Fun' should only really be considered after 1. security and 2. usability, and this CAPTCHA fails on 1. As soon as this CAPTCHA becomes widespread, spammers will have additional incentive to create bots that brute-force it, defeating the point.

Also I think you overestimate the amount of coding required to brute force this particular CAPTCHA.

Re: Chess CAPTCHA

#65
post #28

Earlier quoted context omitted.

But serious spammers would prefer to spend this time writing a bot capable of spamming all forums based on some widely used engine. Cracking this captcha won't give you access to any significant audience.

by this argument, the captcha would become useless as soon as it saw widespread adoption. The idea of a captcha is to be strong against bots even if it was directly targeted by spammers.

No, a captcha is supposed to get rid of spam without annoying the users. If it gets rid of lichess.com's spam without annoying the users, then it is perfect.

Re: Chess CAPTCHA

#66
post #60
post #43

Brilliant building of software. Less than brilliant copy. I would change Black plays; checkmate in one! This is a chess CAPTCHA. Click on the board to make your move, and prove you are human. to This is a chess CAPTCHA... To prove that you are human, click on a black piece, then click on the only destination square that will checkmate. I really don't mean to nitpick, but took me a minute to figure out what to do. Som…

Black plays; checkmate in one! What can be more clear than this? If anything, I'd prefer to have the king I'm supposed to checkmate standing on a red field to make it easier to spot.

Are you supposed to "click-drag" or "click the piece then the cell"? How about on iOS ?

My point is that, while the one-liner captures the idea of the captcha, the summary doesn't explain how to actually execute.

Re: Chess CAPTCHA

#67
post #44
post #43

Brilliant building of software. Less than brilliant copy. I would change Black plays; checkmate in one! This is a chess CAPTCHA. Click on the board to make your move, and prove you are human. to This is a chess CAPTCHA... To prove that you are human, click on a black piece, then click on the only destination square that will checkmate. I really don't mean to nitpick, but took me a minute to figure out what to do. Som…

thanks for the feedback, I will apply the suggested change soon.

Ignore the feedback. Original copy is better.

It is interesting because you can't really A/B test the response time with the different text, since the response time includes the human processing time of the chess problem.

Re: Chess CAPTCHA

#68
post #45

I am fairly certain it would be quicker to program a computer that can brute force a checkmate in one than I can solve these things by hand. You have what, 11 pieces, they can move into 64 positions each (at most, much less in reality). That means a computer must brute force 64*11 = 704 attempts. In other words, no time at all to bruteforce this once you've read the grid. Reading the grid in itself is rather trivial…

Yes, an afternoon of coding to be able to post spam on exactly one website. Until they change the captcha.

Unlikely but not impossible.

I've seen forums get flooded for no other apparent rationale than some random skiddie had nothing better to do for an hour or two than irritate the admins. It being not worth anyone's time to break isn't actually a feature, but it being relatively easy for anyone with time to waste on it is a flaw.

Re: Chess CAPTCHA

#69
post #66
post #60

Earlier quoted context omitted.

Black plays; checkmate in one! What can be more clear than this? If anything, I'd prefer to have the king I'm supposed to checkmate standing on a red field to make it easier to spot.

Are you supposed to "click-drag" or "click the piece then the cell"? How about on iOS ? My point is that, while the one-liner captures the idea of the captcha, the summary doesn't explain how to actually execute.

So add a short explanation at the end.

Starting with "Hey, let's solve a CAPTCHA because I'm not sure if you are a human" and burying information which side the user is supposed to play somewhere in the middle of the text would make it a major PITA.

Re: Chess CAPTCHA

#70
post #28

Earlier quoted context omitted.

But serious spammers would prefer to spend this time writing a bot capable of spamming all forums based on some widely used engine. Cracking this captcha won't give you access to any significant audience.

by this argument, the captcha would become useless as soon as it saw widespread adoption. The idea of a captcha is to be strong against bots even if it was directly targeted by spammers.

CAPTCHA solve a specific design problem. They are not an IETF protocol or solution to be used everywhere. That's kind of the issue. Once a CAPTCHA is worth enough it will be overcome.

The problem is to design a CAPTCHA that implements just enough headache to make it worthwhile not to overcome and at the same time not frustrating users. I think this chess problem uniquely and elegantly solves the problem for the site in question by achieving both.

Then again, I am not familiar with the users, maybe the site is often trolled by chess mastah wanna-bes.

Post reply on HN