Google acquires reCAPTCHA

http://googleblog.blogspot.com/2009/09/teaching-computers-to-read-google.html

by smikhanov • 17 years ago

181 93 17 years ago

googleblog.blogspot.com

I can't believe I didn't see this coming. Given Google's size and mission statement, any company whose business generates new data must partner with Google, sell out to Google, or kill Google if it wants to survive.

antiismist• 17 years ago

That's an interesting insight but it goes too far. For example, Mint.com/Intuit and Facebook can survive independent of Google.

maggie• 17 years ago

who?

spoiledtechie• 17 years ago

Google has approached Facebook to be bought out...

dabeeeenster• 17 years ago

What? Why? You can write your own CAPTCHA or use another provider...Unless I'm missing something?

lucumo5• 17 years ago

reCAPTCHA has some pretty good network effects due to the amount of data they have. reCAPTCHA detects suspect behaviour from IP addresses/ranges/sites etc. and blocks users based on that.

seldo2• 17 years ago

Good move. Google wants to digitize all the books in the world, and reCaptcha does just that. Google could have tried just becoming a client of reCaptcha, but their scale would have crushed reCaptcha, to say nothing of the business risk of outsourcing a key stage of your signup process to a third party.

The logical solution was to buy them and Google-size their infrastructure.

From a personal perspective, I don't think this really changes how I feel about reCaptcha either. They'll still have the same mission -- unless Google stops them reading out of copyright classics and puts them onto scanning in Dan Brown novels, which I think is unlikely.

amanfredi2• 17 years ago

Google already has a great captcha for their signup process. The primary motivation must have been the OCR benefits.

shimon• 17 years ago

Or the team.

seldo2• 17 years ago

Isn't that what I said?

fuzzmeister2• 17 years ago

Since most modern books either have high-quality print copies or digital copies available, I doubt that this technology will be used for much else than scanning old books for the foreseeable future.

gehant• 17 years ago

Since reCaptcha tries to differentiate humans from computers/bots, I find it ironic that the same reCaptcha technology is being used to improve the accuracy of how computers scan text...

ludwig• 17 years ago

Only because every time it gets stuck, it "asks" a human.

elemenohpee• 17 years ago

Yeah I thought the article was a little misleading on that point. They made it seem like the human input was improving the OCR algorithms.

apowell3• 17 years ago

I preferred thinking that the CAPTCHAs on my websites were doing a bit of good for the world - now I'm just facilitating free labor for Google's benefit.

brown9-22• 17 years ago

Well I think if anything that you are helping computers perform OCR better, which I would consider to be "doing a bit of good for the world", but I guess it depends on if you associate Google with "evil".

sp332• 17 years ago

Currently, reCaptcha is digitizing old copies of the New York Times. I don't think that's changed.

apowell3• 17 years ago

No, but the deal was just announced today. I wonder if before long Google will use reCAPTCHA to digitize books as part of the Google books project - all without the permission of the original copyright owners.

Edit - To clarify, I think that making information in the public domain more accessible is a very worthwhile project.

lsb3• 17 years ago

You're still getting free bot-prevention. If you don't like it, use something like Damien Katz's Negative CAPTCHA (hide a field with CSS, call it email, and wait for a bot to fill it out, and check that that field is empty server-side).

secret• 17 years ago

That's clever!

ErrantX• 17 years ago

in what sense was it doing good? I dont think any of their current content has been seen by anyone much (It is old NYT's I think... so I dont know if they do it under contract for NYT?)

blasdel• 17 years ago

I remember reading at least a year after its introduction that nothing had been done with the OCR data it had produced to date.

It's only very recently that they started talking publicly about their relationship with the NYT, and they've still said diddly-squat about public availability of the results.

fuzzmeister2• 17 years ago

In my opinion, digitizing old books and newspapers is doing good for the world no matter who is profiting from it. The information will still be made publicly available on the internet, which it is not now. More information is a good thing.

Keyframe• 17 years ago

I haven't even realized that recaptcha was a company.

henning• 17 years ago

I thought reCAPTCHA was a hip university research project.

patio11• 17 years ago

They learned from the Google school of public relations. ("What, make money? Hah, hah, we're just a bunch of geeks who like interesting problems, no crass lucre here, no siree!")

jcl• 17 years ago

These are the same guys who sold the hip university research project "ESP Game" to Google.

http://en.wikipedia.org/wiki/ESP_game

breck2• 17 years ago

Me too. i thought it was a non profit for some reason.

stingraycharles• 17 years ago

Wait. I must be missing something:

Since computers have trouble reading squiggly words like these, CAPTCHAs are designed to allow humans in but prevent malicious programs from scalping tickets or obtain millions of email accounts for spamming. But there’s a twist — the words in many of the CAPTCHAs provided by reCAPTCHA come from scanned archival newspapers and old books. Computers find it hard to recognize these words because the ink and paper have degraded over time, but by typing them in as a CAPTCHA, crowds teach computers to read the scanned text.

The way I understand this, is that the user is presented letters from archival newspapers and must type in the text he sees, and recaptcha uses that text to improve OCR. But doesn't that imply that recaptcha was unable to interpret the scanned text before ? If so, how can it then verify the correctness of the text the user types in ? If not, how exactly is this helping OCR ?

apowell3• 17 years ago

reCAPTCHA presents two words. One is known, the other is unknown. The idea is that if you type the known word correctly, then you've typed the unknown word correctly as well. It also shows the same unknown word to many people as a distributed accuracy check.

fizx3• 17 years ago

  > But if a computer can't read such a CAPTCHA, how does the 
  > system know the correct answer to the puzzle? Here's how: 
  > Each new word that cannot be read correctly by OCR is 
  > given to a user in conjunction with another word for which 
  > the answer is already known. The user is then asked to 
  > read both words. If they solve the one for which the 
  > answer is known, the system assumes their answer is 
  > correct for the new one. The system then gives the new 
  > image to a number of other people to determine, with 
  > higher confidence, whether the original answer was 
  > correct.

http://recaptcha.net/learnmore.html

jchonphoenix3• 17 years ago

So reCaptcha uses a statistical accuracy and machine learning algorithms to compare the user input for the same word over hundreds of users. Thus by doing this they minimize the probability that a human who incorrectly deciphers a word skews their data.

Also reCaptcha's present two words. One of which is known, and used as a normal captcha, the other of which is an unreadable word. Thus if a someone passes the captcha word, its somewhat assumed that he also correctly typed in the unknown word because the words are presented in randomized order.

Finally, as a funny anecdote, Luis told me once of this time that they noticed there was a captcha farm in latin America paying pennies for poor latin american's to solve reCaptcha's for them in order to gain the ability to generate illegal spam. Luis started sending them whole sentences of reCaptcha's and eventually made it to full paragraph's. Ironically, the reCaptcha farm continued to solve these captcha's. He eventually stopped their activity, but he said the data they generated was some of the best he's ever gotten... :P

biohacker42• 17 years ago

I read this as Google basically giving up on CAPTCHA. Let me explain.

For a while google had one of the hardest CAPTCHAs but bots just keep getting better, and they were cracking it more and more often. But you can't just make the CAPTCHA even more difficult, it was already fooling a lot of the humans.

Note that a bot does not need to successfully solve it 100% or even 90% of the time. I'm not sure of what the exact figure is but at some point the bot reaches parity with humans even if it only succeeds say 25% of the time. That's because on average now it only takes 4 guesses to guess correctly.

And I don't think reCAPTCHA is stronger then the multicolored CAPTCHA google had (still has?)

I think google is realizing that they just can not stop the best CAPTCHA cracking bots, maybe they can stop a lot of them, or a lot of the not so smart bots.

But they also can't just give on CAPTCHA, and let anyone and any bot in without even trying.

Thus reCAPTCHA because you might as well do a little public good while you're at it. If nothing else, you've at least made some old texts more readable.

mixmax2• 17 years ago

Some users from 4chan managed to hack recaptcha and embarrass Time magazine seriously at the same time not long ago.

Basically they stuffed the ballots on the Time online voting page where users could vote for most influential person of the year. Most influential person ended up being Moot, founder of 4chan. Just to rub it in they managed to spell "marblecake also the game" out of the first letters of the top 21 entries.

Note: This hack shows more about Time's incompetence than recaptcha's.

In-depths story here: http://musicmachinery.com/2009/04/27/moot-wins-time-inc-lose...

mrduncan• 17 years ago

Thanks for bringing that up, I'd almost forgotten about that.

The way I understand it, reCAPTCHA gives you 2 words to analyze, one which reCAPTCHA "knows" and one it is trying to learn about. As long as you get the word it knows about correct, it'll say you're a human. You're answer to it's unknown word is simply stored and (I'd assume) analyzed until it has enough responses to consider it a known word. Knowing this allowed 4chan users to nearly cut their response time to the captchas in half.

I'd be fascinated to hear more details (or be corrected) on how reCAPTCHA works if anyone has them.

sam_in_nyc3• 17 years ago

I think you've pretty much got it right. Once there's a significant amount of "agreement" on what a word says, reCAPTCHA will assume it's correct. My guess is it will keep unknown words in its "unknown" pool until a minimum amount of responses are given, AND the responses are in agreement over a minimum (likely very high) percentage.

brown9-22• 17 years ago

No, they didn't come close to "hacking recaptcha":

Update – Just to be perfectly clear, anon didn’t hack reCAPTCHA. It did exactly what it was supposed to do. It shut down the auto voters instantly and effectively. The only option left after Time added reCAPTCHA to the poll was a brute force attack. Ben Maurer, (chief engineer on reCAPTCHA) comments on the hack: “reCAPTCHA put up a hard to break barrier that forced the attackers to spend hundreds of hours to obtain a relatively small number of votes. reCAPTCHA prevented numerous would-be attackers from engaging in an attack. In any high-profile system, it’s important to implement reCAPTCHA as part of a larger defense-in-depth strategy”. As Dr. von Ahn points out “had Time used reCAPTCHA from the beginning, this would have never happened — anon submitted tens of millions of votes before Time added reCAPTCHA, but they were only able to submit ~200k afterwards. And to do this, they had to resort to typing the CAPTCHAs by hand!” One thing that Time inc. did that made it much easier for the anonymous hack was to allow leave the door open for cross-site request forgeries which allowed anon to create a streamlined poll that never had to fetch data from Time.com.

tlrobinson2• 17 years ago

While not completely cracking it, didn't they figure out that they could skip one of the two words, and which word to skip effectively halving the time it takes to solve the captcha?

mixmax2• 17 years ago

That's why I wrote This hack shows more about Time's incompetence than recaptcha's.

Sorry if I didn't make it clear enough that the fault lay with Time and not recaptcha.

ALee• 17 years ago

4chan users were never able to successfully break recaptcha without some significant brute force techniques as detailed in the blog post, so there is still a lot of hope yet for recaptcha.

gloob• 17 years ago

That said, I doubt the attacks perpetuated by 4chan are the wrong place to start searching if what you're looking for is intelligent attempts to crack the system. They are among the truest supporters of the rule to "When in doubt, use brute force." The fact that they fell back on that technique probably means very little for the actual security of recaptcha.

beeker• 17 years ago

Is Louis von Ahn going to work for Google as part of the deal?

tlrobinson2• 17 years ago

His name is on the blog post, so I assume he is.

He's had a lot of neat ideas which align well with Google. I think he'd be a great addition to their team.

fizx3• 17 years ago

He's a professor at CMU. I imagine some grad students will go to Google, but I'd imagine he'll stay at CMU?

http://www.cs.cmu.edu/~biglou/

jchonphoenix3• 17 years ago

I'm currently doing research for Luis as part of Gwap, and as far as I can say, he's going to remain on the faculty at CMU but also work for Google out of the Google PGH offices. He's no longer teaching 251, however, which is what he's famous for around here (at least to students). What this means for me, however,...

fizx3• 17 years ago

I find it funny that Luis also posted:

http://vonahn.blogspot.com/2009/07/hottest-people-in-cs.html

joshu• 17 years ago

Heh. Now there are three TR35s from the same year at Google.

DarrenMills• 17 years ago

Righting your own CAPTCHA seems like a small task for Google. reCAPTCHA wasn't exactly encroaching on Google's market share... so what exactly did this get Google? I think they have a bigger plan, as always.

Ideas?

mercury888• 17 years ago

yep - they are going to monetize captchas. How typical of google :)

sam_in_nyc3• 17 years ago

It's my guess Google is in this for the cookies and analytics that can be gathered by (however many) websites that use ReCAPTCHA.

As a trivial side-note: When encountered with a ReCAPTCHA, I'll fill out one of the words and put in gibberish (or other text) for the other. For some reason I find it satisfying to "pull a fast one" on any captcha service.

mseebach• 17 years ago

> For some reason I find it satisfying to "pull a fast one" on any captcha service.

Why? What do you achieve except being told you're wrong every once in a while? I mean, you're trying to bother a machine. Isn't that a bit like a reverse Turing test?

I suspect the amount of noise that ReCAPTCHA filters out from automatic attempts is several orders of magnitude larger than anything any group of actual humans can generate.

ryanpetrich• 17 years ago

Unless you happen to be 4chan

sam_in_nyc3• 17 years ago

It takes no extra effort to enter in the wrong item, so the cost of doing so is about zero.

As far as what satisfaction I gain from it... I suppose I find it to be a sort of rebellious act. Also, I did not get accepted into Carnegie Mellon.

yarapavan• 17 years ago

A list of about 50 scientific articles on "captcha" available at http://www.citeulike.org/tag/captcha

dunk010• 17 years ago

Think of all the sites which use recaptcha for their signups - google will get some interesting stats through this.

gengstrand• 17 years ago

It's a brilliant move in using collective intelligence. You get better quality CAPTCHAs. You get more accurate digitization on the cheap. I go into more detail on this at http://it.toolbox.com/blogs/future-of-work/google-acquires-r...

Google acquires reCAPTCHA

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