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Chess CAPTCHA

en.lichess.org

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Re: Chess CAPTCHA

#41

Post by solistice »

oneeyedpigeon wrote: post #33
NamTaf wrote: post #15

I thought image recognition on that would be trivially easy to compute? You could identify each piece, then just analyse it to work out the 1 move. As a layman, it seems less computationally difficult to solve that than a state-of-the-art captcha currently?

Not even image recognition. The chessboard is nicely marked-up with relevant classes (e.g. 'bishop') for each piece; would be very easy to automatically solve. However, as others have said, since it's such a narrow target, it's probably not worth cracking.

The fact that it's a chessboard captcha with no relevant target behind it proably outweights even the satisfaction of cracking it. "Hey, I broke the chessboard captcha" "You did WHAT? I loved that thing!"...

Re: Chess CAPTCHA

#42

Post by C1D »

mich41 wrote: post #34
C1D wrote: post #31

Earlier quoted context omitted.

Yes but for some people that don't know how to play chess it would be very hard.

I'd hazard a guess that most people posting on a chess forum know the rules. And as somebody else pointed out, maybe they don't want new topics asking what are the possible moves of a queen.

>for some people that don't know how to play chess it would be harder Opps.. I didn't realize.

Re: Chess CAPTCHA

#43

Post by edw519 »

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. Sometimes the thing that makes the biggest difference for us programmers is not our communication with our compiler but our communication with our users.

Great job. Thanks to you, I just announced I won't be ready for brunch for another half hour. Sigh.

Re: Chess CAPTCHA

#44

Post by ornicar »

edw519 wrote: 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.

Re: Chess CAPTCHA

#45

Post by Swizec »

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 since you only have a small number of clearly distinguishable pieces to recognise.

So after an afternoon of coding, I could have a computer that solves this CAPTCHA in a few seconds. As a human I need more than 30 seconds just to read the current situation on the board.

Re: Chess CAPTCHA

#46

Post by bmuon »

munchor wrote: post #4

I know a lot of people are commenting on how effectively this could be used, but I'm simply amazed at how clever this is. The idea behind it is very interesting, but it obviously can't be used as a mainstream way of human detection. I think what matters here is the really well-made implementation with HTML5. Great job!

There is no HTML5 here, just plain s and JavaScript. But that doesn't make it any less good. It's really polished.

Re: Chess CAPTCHA

#47

Post by fosap »

draq wrote: post #26

This is a very creative CAPTCHA. However, computers are rather good at playing chess, so a chess problem is probably the least thing you want to use to distinguish between humans and computers (unless your aims is to keep stupid humans out). Other possibilities: guess fruits ( http://www.eurekalert.org/pub_releases/2013-03/ip-std030613.... ), human emotions, animals etc.

or maybe go? Computers suck at go.

Re: Chess CAPTCHA

#48

Post by alexjeffrey »

mich41 wrote: post #28
bdg wrote: post #21

Can brute force answer from the server quicky: http://en.lichess.org/captcha/0nbdeigw?solution=a1+a2 returns either 1 or 0. The total complexity of this to brute force is 768 possible moves. Most of us here could write a bot to spam their site with less than 30 minutes of time and effort.

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.

Re: Chess CAPTCHA

#49

Post by nawitus »

fosap wrote: post #47
draq wrote: post #26

This is a very creative CAPTCHA. However, computers are rather good at playing chess, so a chess problem is probably the least thing you want to use to distinguish between humans and computers (unless your aims is to keep stupid humans out). Other possibilities: guess fruits ( http://www.eurekalert.org/pub_releases/2013-03/ip-std030613.... ), human emotions, animals etc.

or maybe go? Computers suck at go.

They certainly beat the average human (because the average human doesn't even know how to play Go).

Re: Chess CAPTCHA

#50

Post by Inversechi »

edw519 wrote: 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…

Some of the captures I have noticed more than one solution, perhaps modifying the suggested words even further is required.
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