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Chess CAPTCHA

en.lichess.org

71–80 of 171 posts

Re: Chess CAPTCHA

#72
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…

I like the original wording because it is exactly how chess problems are typically introduced. I'm not sure the usefulness of this anywhere beyond a chess - related site, but I agree - - it's absolutely brilliant! I wish I had thought of it.

Re: Chess CAPTCHA

#74

Earlier quoted context omitted.

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…

The design itself could be improved though to make it stronger against scripting, though. For instance, there's no reason the values for the pieces and the boards necessarily need to be human-readable and to follow the notation of chess in the code itself, those variables could be randomly generated per load, perhaps with a salted hash. That could also serve as csrf protection maybe.

Re: Chess CAPTCHA

#75
I'd say that the next step would be a CAPTCHA for Go -- creating an efficient Go player is still an open problem, and we could crowdsource the AI research to spammers!

Re: Chess CAPTCHA

#76
post #35

Earlier quoted context omitted.

I know what a ping is. Why would someone do that on a website? It just seems pointless and causes additional load on the server.

lichess.org is a game server, and supports real-time playing. The ping is a critical information when you play fast games, it helps to diagnose lagging when it happens.

Ah. I thought it was just a forum/web-site. That would make sense, then.

Re: Chess CAPTCHA

#77

Earlier quoted context omitted.

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…

if the idea of the chess captcha is to be used once on a single site, (ignoring the fact that it's a chess captcha for a chess community) it's very over engineered. Jeff Atwood gets away with a captcha where all you have to do is type "orange" to post a comment[1] and even that manages to mitigate a lot of spam.

http://www.codinghorror.com/blog/2008/03/captcha-is-dead-lon...

Re: Chess CAPTCHA

#78
Perhaps a bug. Chrome on my Galaxy S3 showed the white's queen (and I believe bishop) as the color of the background. This was a problem because they were on a grey tile. When I first tried the captcha, the board arrangement looked like white had a king and a few pawns in the lower right and that black had two queens and a bishop in addition to their king at the top of the board. The white, according to my incorrect reading of the board, instantly looked like it was in check, but the captcha was saying that it was white's turn to put black into checkmate. I was completely confused and tried multiple times to move the "black" queen into a position that would checkmate white believing the captcha text to just be incorrect or misleading. After a couple failed attempts, I realized the queen I was trying to move was grey, not black, and then I solved the captcha.

In this case, the captcha took way too long because the pieces were hard to distinguish and the captcha text was unclear. I think that captchas should be something you can do near instantaneously. However, I really like the concept and the trying of a new approach.

I've had success implementing what I feel to be very simple captchas: solve simple arithmetic problems. I'm sure a parser could be created simply enough that would solve them, but I have had zero forum spam in a couple of small forums that use it.

Re: Chess CAPTCHA

#79
post #44

Earlier quoted context omitted.

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.

Sure you can. You're just adding two (probably normal-ish) distibutions: the distribution of human response times for processing the chess move, and the distribution of human response times for parsing the instructions.
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