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Web Users Angered by Anti-Spam 'Captcha'
Carl Bialik from WSJ writes "Captchas -- the jumbles of letters that users must type to gain access to some websites -- are a growing irritation, the Wall Street Journal reports. But programmers hope to make new variations that are both easier to decipher and harder to crack. From the article: 'Some captchas have been solved with more than 90% accuracy by scientists specializing in computer vision research at the University of California, Berkeley, and elsewhere. Hobbyists also regularly write code to solve captchas on commercial sites with a high degree of accuracy. ... Henry Baird, a professor of computer science at Lehigh University who studies PC users' responses to the codes, has been working with colleagues to develop new generations of captchas that are designed to be easier on humans but baffling for computers.'"
I couldn't read the article. They wanted me to type CapTcha. Or was it Cap7cha? Oh well?
And All I Ask is a Tall Ship And a Star to Steer Her By
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I prefer kitten auth.
liqbase
I had heard once of a very cunning strategy around captchas. I'm not sure if this is true but there is a story of a p0rn site making large sums of cash by selling key sets to the images. Certain sites would not dynamically generate images but instead rely on sets of images with protected keys as a captcha.
In order to use the p0rn site he ran, you had to either pay money or spend time identifying captchas. He would then store them in a database and match it up with a checksum of the image. When he had completed a site's captcha key set, he would sell these lookup tables to anyone with money.
All they then had to do was write their program to do a checksum of the image (or the image itself if he had stored it) and then plug the word from the database into the page for verification.
With the introduction of splashers that spatter the statically stored images with lines or dots, the image is stored and a something like an edit distance is applied to it to find the closest match. Once that is accomplished, it references the keyword out of the database. You turn up the splasher and you risk the user not being able to figure out the word.
It seems that evil always finds a way. This is why captchas should always be dynamically generated on the fly from a very large dictionary! Check out Securimage for PHP.
My work here is dung.
"Some captchas have been solved with more than 90% accuracy by scientists specializing in computer vision research at the University of California, Berkeley, and elsewhere."
Hell, that's better than my average. They are getting so cryptic, it seems I get them wrong about 25% of the time these days.
-josh
Just throwing this out, but maybe there should be a very basic question asked instead? Since these already presume literacy, maybe something like:
Which of these is a number: A 2 R P?
Seems that regardless of what they come up with there's going to be some part of the population that won't figure it out anyway, and if the whole point is to confuse auto-registerers, then I'd think it'd be harder for those to account for every possible question and answer set.
(Yea, it's in TFA, but mentioned like an aside...)
The captcha concept breaks down if the user can't see the image, either through the limitations of their browser (links) or the limitations of their eyes. A US government site would have a hard time justifying captcha in light of their legal and moral responsibilities to the disabled citizenry.
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...unless you are blind. Some sites have alternate audio versions for the vision-impaired, but it's still a problem.
And even if you aren't blind, I've run into many a captcha that I couldn't decipher. Poorly designed sites may delete the entire content of your post if you fail the captcha, but I guess that's a design issue for another topic.
Not sure if cryptic is the right word
Sig cannot be found.
If I wanted to be really sadistic, I could instead present site readers with a sentence, in which they have to fill in either "their," "there," or "they're."
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The paradox is, if a site has one that works really well for them, other sites will want to use it as well. As other sites use similar or identical systems, it becomes exponentially more beneficial for crackers to crack. So, as soon as something's good enough to use, it becomes good enough to crack.
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And yet, the discussion of the article will prove to be much more illuminating than the article.
What's wrong with an article being a spark for more in-depth discussion? How else are things rarely discussed in the media and never in depth (like most tech topics) going to be discussed on slashdot?
Sure, I know this post (and the parent) are off-topic, but it bugs me when people think that the purpose of slashdot is just to accumulate articles... that's what RSS feeds are for.
The discussion is what keeps me coming back, and typically, no matter how moronic the article is, there are several posts that give the kind of information that I wish was included in the article (but isn't). At the very least, people provide links to more comprehensive information and/or discussion of the issues concerned.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
Captchas are not hard to crack, now that someone has produced my favorite crack strategy. A "man in the middle" attack server hits pages with captcha challenges. That server advertises a "free porn" website, presenting to its human audience the captchas it hit. The porn seeking humans decode and enter the captchas, get the porn (or not), the server sends their entries to the original captcha page, and gets past them as often as humans seeking porn would. There's so many humans seeking porn that the middleman transactions happen in realtime, indistinguishable from direct human responses to the original captcha.
This is v1.0 of the Matrix, where human brains are harnessed to solve problems by a more powerful and wise, though less "intelligent" computer network.
--
make install -not war
... it is annoying for users. Sometimes I get it wrong because I can't tell if the captcha technique they are using is case sensitive and I can't always tell the case of the character! Sometimes a lower-case L can be confused for a number 1 or vice-versa. So yeah, it's REALLY annoying.
HOWEVER. A short and simple multiple-choice or true-false quiz might determine with some level of accuracy if the poster is a person or not. Simple stuff like a random image of a sheep, a lion, a bear or a whale with a radio button selection below it. It's easy to run through, it shouldn't require much skill from the user and has the potential to confuse interpreting software a lot more.
This approach could also even be ENTERTAINING to the user in that funny pictures could be used in the image interpretation drill. Such questions could be "Is this person having a good day?" and you can put all manner of interesting images in there for a true-false scenario. Being an entertaining method will definitely win fans. Being tedius, stressful and mistakable will lose fans.