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Chess CAPTCHA

en.lichess.org

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Re: Chess CAPTCHA

#81

Post by adamt »

The FEN notation(1) state of the the board is in the HTML:

      data-fen="7r/3k1ppp/3bpn2/1p3P2/1PbP4/2r2P2/P2K1Q1P/q5NR">
Any chess engine could load this and solve these problems in milliseconds. Which is far easier than most captchas that require moderately sophisticated image processing.

(1) http://en.wikipedia.org/wiki/Forsyth%E2%80%93Edwards_Notatio...

Re: Chess CAPTCHA

#82

Post by xymostech »

canttestthis wrote: post #64
rweba wrote: 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.

I can assure you, this CAPTCHA will not become widespread, because most people don't know how to play chess. It's specifically on a forum about chess, so it's reasonable there, but anywhere else would be ridiculous.

I will agree that coding a brute force method would work well, though.

Re: Chess CAPTCHA

#83

Post by yen223 »

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…

Or how about:

    A CAPTCHA appears before you,
    in form of a chessboard to prove,
    that you're a real user,
    and not a computer,
    by checkmating WHITE in one move.

Re: Chess CAPTCHA

#84

Post by dpcan »

vfl0 wrote: post #18

Not gonna lie, it took me a while to figure out because I had no idea what a checkmate was.

Great point. My first thought was, anyone who doesn't know how to, or doesn't like to play chess would not create a topic on this page.

The game-as-captcha idea is good tho, IMO.

I was in a forum talking about this with fellow game devs a while back. Something like a mini platformer that required you to run and jump your character to a flag, for example, might be interesting, or solve a block-fit-style puzzle, or rotate pieces to solve a puzzle, and so on.

Re: Chess CAPTCHA

#86

Post by nmcfarl »

adamt wrote: post #81

The FEN notation(1) state of the the board is in the HTML: data-fen="7r/3k1ppp/3bpn2/1p3P2/1PbP4/2r2P2/P2K1Q1P/q5NR"> Any chess engine could load this and solve these problems in milliseconds. Which is far easier than most captchas that require moderately sophisticated image processing. (1) http://en.wikipedia.org/wiki/Forsyth%E2%80%93Edwards_Notatio...

It would have been easy to have just stored that bit of session state to the server.

It’d also be pretty easy to alter the HTML board to a prerendered image with imagemap click detection. At which point someones writing custom image feature detection software to break your captchas.

Of course, this mainly works because of the obscurity, even with the upgrades. And since someone’s already going to have to write custom software to break this I’m not sure it’s worth it to upgrade - as I doubt it’s worth anyone’s time to do write the minimal software that needed now.

Re: Chess CAPTCHA

#87

Post by EGreg »

Easy captcha to solve by a computer, no? Just hook up a program that recognizes the pieces etc. Not to mention requires a human to know the rules of chess.

However, it may be said that no one would put the effort to make captcha solvers for everything... unless captcha crackers pooled together.

That makes for an interesting question. Since to solve CAPTCHAs you have to build progressively stronger UIs, can it be said that if there sprung up a "CAPTCHA plugin industry", with people using captchas of everyday things, then the combined solver would eventually be some really versatile AI?

I remember recommending that people just send in pictures of street signs etc. as this would be much better than the best CAPTCHAS right now

Re: Chess CAPTCHA

#88

Post by disgruntledphd2 »

carbocation wrote: post #79
shawn-butler wrote: post #67

Earlier quoted context omitted.

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.

Human response times are almost never normally distributed. They can't be, as a matter of fact as negative response time is an impossibility.

In any case, they are typically long tailed and weird looking. Not normal, at least in my experience of working with them

Re: Chess CAPTCHA

#89

Post by arb99 »

Crap captcha if it became popular... to easy to brute force. I know its for a chess site but it isn't even very user friendly

Re: Chess CAPTCHA

#90

Post by hk__2 »

yen223 wrote: post #83
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…

Or how about: A CAPTCHA appears before you, in form of a chessboard to prove, that you're a real user, and not a computer, by checkmating WHITE in one move.

I would change "a real user" with "a real user who doesn’t use a screen-reader". That’s less funny, but more accurate.
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