What's up, bot? Google tries new Captcha method

http://news.cnet.com/8301-17939_109-10222514-2.html

by nickb • 17 years ago

58 33 17 years ago

news.cnet.com

qeorge2• 17 years ago

That's a cool idea, but they'll still have to provide an audio CAPTCHA for blind users, which is easy to solve.

markbao• 17 years ago

Really?

https://www.google.com/accounts/NewAccount

ctingom• 17 years ago

Wow, I could barely make out the audio captcha!

qeorge2• 17 years ago

Wow, that's incredible how much noise they've added. I couldn't make it out myself. Its bordering on unusable IMHO.

Still, I wouldn't be surprised if a computer could get 1 in 4, which is plenty to be effective. They're still only using the 10 digits for the signal.

DavidSJ• 17 years ago

Actually, I think the noise proves his point. The fact that adding so much noise was necessary means computers are pretty good at solving that problem, and it has to be made next to impossible for humans before computers can no longer solve it either.

omarchowdhury2• 17 years ago

A lot of spam operations use humans to solve captchas, so this isn't much of a change for them (actually could make it easier for them).

rarestnews3• 17 years ago

Also it's sometimes used as porn-bait (i.e. enter captcha to enter the "free" site).

Human solving is pretty cheap too. I've heard quotes about $2 for 1000 captchas. I guess with 1 click instead of 5-7 letters + enter - it's going to be cents per thousand soon enough, cause you don't even need to know keyboard well or type fast enough. So, I'd say that might be a step backwards.

DenisM2• 17 years ago

I've heard this pron meme before, but didn't see any actual proof. Do you have sources?

Hexstream• 17 years ago

Yes, however spammers are known to operate on very tight margins (they make a few pennies per million users or something) so even slight additional operating costs can seriously affect their bottom line, possibly sending a profitable operation into the red.

So eventually forcing spammers to employ humans instead of bots is not for naught.

omarchowdhury2• 17 years ago

This is not true.

It depends on what type of spam we're talking about.

The obvious here is social network spam (you don't enter captchas to send emails), which is where captchas are most used against spammers, can be very profitable ($xxx per x,xxx-xx,xxx users).

amix2• 17 years ago

I have implemented something similar called "Visual captcha", where the user has to pick the cat out from 6 randomized Flickr pictures. The code is freely available and should not be hard to integrate into your own projects. Read more on: http://amix.dk/blog/viewEntry/19338

henning• 17 years ago

Is that really effective? Just take some face detection code and have it learn what cat fur looks like instead.

amix2• 17 years ago

It's ok effective judging by my usages and I could just iterate over this solution if someone brute forced it or implemented a "cat fur detector" (which for my uses is pretty unrealistic).

Battling spammers is really a battle where you implement better protections and they implement better attacks. The conclusion so far has been that it isn't possible to check-mate them - - and it's very unlikely it will ever happen as a lot of spammers use "human bots"...

Using visual captcha is much more user friendly thought, so it's a win for the users.

stevenrace• 17 years ago

There is actually a 'Google Tech Talk' on detecting cats (versus other shapes) from images:

http://www.youtube.com/watch?v=-w72_VwSj6A

  Is it really that easy?  I would think flagging for texture would be difficult, as it's
 likely indistinguishable from noise (data, shadows, clothing..).  Approximating shape/avg.
 contour is likely easier than looking for fur patterns.

  Any suggestions on books/papers/etc on image recognition?

liuliu• 17 years ago

the real challenge is to collect enough pictures so that your database could not be broken by brute-force. Of course you can use Flickr's tag to identify it, but there are many mis-matches. Google's method solved this problem because image orientation is a heavily studied problem in computer vision which could take advantage of computer to help creating large visual database and then prune out the easy case for computer.

thorax• 17 years ago

Flickr is harder, I'd use a different database.Doing image searches using existing online images is becoming easier (e.g. TinEye). An evil bot would just do image searches against flickr for each of those images and read/scan the tags there to be sure.

whughes• 17 years ago

What is to stop a bot from just clicking randomly? A 1/6 chance of registering an account is good enough for botting purposes. That's the problem with these multiple-choice solutions. They simply aren't strong enough protection against a flood of tries.

vaksel• 17 years ago

can't someone figure out an anti-spam method that doesn't require a captcha? I mean its not like captchas even work, I'm yet to see one that works 100%

jonknee• 17 years ago

Craigslist's phone verification works well. The downside is it's expensive to run and hard if not impossible to scale globally.

Goladus• 17 years ago

The best you'll ever get is human to human contact.

But that doesn't scale cheaply.

shader• 17 years ago

And there is the essence of the need for captchas ;)

You need to scale, so you employ computers instead of people. Now you have to have computers run a reverse turing test. Otherwise, it's much easier for spammers to scale as well.

It's easy to cut down on spam if you don't accept any incoming mail.

pavel_lishin2• 17 years ago

I think one fascinating aspect of this whole thing is that by creating tougher and tougher captchas, Google and the like are actually helping make great strides in the field of image recognition by forcing spammers to adapt.

snprbob86• 17 years ago

The truth of the whole thing is that Google primarily relies on _behavior_ to detect bots. Captures are just an added layer of defense and serve as a pretty good way of seeding the behavior database. If some user appears to be a bot, serve them a captcha. If they fail, then that behavior was bot-like. Google is using captchas as a way to learn image recognition as well as bot behavior patterns. They know full well that they won't be able to rely on captchas for ever, but they will sure as hell collect as much data out of them as possible.

rarestnews3• 17 years ago

Actually I'm really tired of that Google's attempts. The other day I tried to find a something like a .txt file containing all the verbs. I tired searching for "finding resting searching" without quotes, Google kept giving me "find rest search", so I tried quoting it: " "finding" "resting" "searching" ", and adding more and more. Most of those were in anchors, not in text, I added: "allintext:"finding" ..." and here it is: "Looks like you are a bot! I can't allow you search for that." :)

Sometimes it's really tempting to write "Google" into Google. :)

What's up, bot? Google tries new Captcha method

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