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Hardest captcha ever?

random.irb.hr

41–50 of 125 posts

Re: Hardest captcha ever?

#42
What answer does it want?

I got "-6-7x7". Does it want proper order of operations applied, giving -6-49=-55? Or does it want it the silly way that most (I suspect) people are going to do it, left-to-right without respect to order of operations, -13x7=-91?

(oops, the asterisks give italics rather than multiplication!)

Re: Hardest captcha ever?

#43
That's funny. I wonder if that encourages people who otherwise wouldn't sign up. It obviously self selects your clientele. I might need to implement a "2 trains leave" problem for my captcha.

Re: Hardest captcha ever?

#44
One thing that's occurred to me -- there's obviously an asymmetry of effort in captchas. Reliable proof that someone is human is very hard. What about reliable proof that something is not human, but an automaton? Can we make this stronger, and make it reliable proof that something is a particular automaton?

It seems to me, the answer is Yes. This is actually very powerful and useful for security. (Even if you can only count on the first time it's answered.)

Re: Hardest captcha ever?

#45
post #11

I don't think it would be hard to do, in fact, they reverse the whole point of a CAPTCHA. A CAPTCHA is supposed to be a task that is easy for humans, but difficult for computers. High-level mathematics is difficult for humans but easy for computers. They do have some success of telling computers and humans apart, though.

High-level mathematics is difficult for humans and provably impossible for computers.

Re: Hardest captcha ever?

#46
post #3

Most of these are really easy. I got a partial derivative of a constant. And honestly, if you can't answer basic math questions, you probably have no use for a quantum random bit generator.

and besides, I'm not entirely sure that these are "unbreakable" whatsoever. If you really want to break this, I'd do some math-specific OCR + WolframAlpha...

Re: Hardest captcha ever?

#47
post #27

Earlier quoted context omitted.

Because a computer is very good at solving basic maths questions? All this does is simplify the captcha for machines to solve, whilst complicating it for humans (basic maths is easy for most but it's still one more logical step then 'type out the 5 letters you see'). Instead of 26 upper and lower-case characters, and often just a random string (so we can't make a best guess vs a dictionary), we now just have ten char…

As you stated: If computer wanted to hack it - sure it is easy enough. But I was looking for a easy way to do some verification. I asked this because I was creating a reddit clone and wanted a captcha system. I detest the ones that exist right now.

The point of most captchas is to stop someone from writing a program that abuses your system. If you're not doing that, what exactly are you "verifying"?

Re: Hardest captcha ever?

#48
post #3

Most of these are really easy. I got a partial derivative of a constant. And honestly, if you can't answer basic math questions, you probably have no use for a quantum random bit generator.

I'm not sure I'd consider calculus to be a basic math question, except in the context of uses where you have a real need for this level of randomness.

Re: Hardest captcha ever?

#49
Dumbest CAPTCHA ever.

It's a math problem - which computers are great at - in highly readable text; which they're pretty good at. I expect someone talented could break it in an automated fashion in a day or less.

I don't know why they don't just throw up an fairly large image of a bunch of animals, then say "Click the cutest kitten" or something that's purely subjective, and relies on human recognition abilities rather than computational ones. Maybe two of those in succession in case a computer gets lucky? Using the same method recaptcha does. Show two images, one with a known heat-map of clicks showing where people think the kitten is, to test them, and another one for them to develop the map on the new picture for future tests.

Re: Hardest captcha ever?

#50
post #11

I don't think it would be hard to do, in fact, they reverse the whole point of a CAPTCHA. A CAPTCHA is supposed to be a task that is easy for humans, but difficult for computers. High-level mathematics is difficult for humans but easy for computers. They do have some success of telling computers and humans apart, though.

If the math problem were squiggly and hand-drawn (i.e., as if on a chalkboard), we might have a more effective CAPTCHA.
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