Userscripts.org

Agreed!

lol, guess I'll think of trying to make one someday as well (*trying* :p)

Well, I've written my JPEG decoder now and it functions correctly, although it takes quite a long time to decode the JPEG: 1.5-2 seconds on my computer for a 300x72 greyscale image, that's probably why people don't typically write them in javascript. Anyway that processing time (during which the browser freezes) combined with the fact it will almost certainly be necessary to refresh the captcha image several times until the script could be somewhat confident about a word mean it's probably impractical to try to break the captcha purely in javascript since you could just type the captcha in well before a userscript would be able to fill it out.

It's possible my code could be optimised a lot, I knew nothing about JPEG compression/decompression 2 days ago so I don't know the most efficient ways to decode them. If anyone wants to look at it (especially people who know a lot about JPEGs or how to optimise inverse discrete cosine transforms) I put it up at http://userscripts.org/scripts/show/38940. It only works on greyscale images and I've only tested it on the captcha image on http://userscripts.org/signup.

it's probably impractical to try to break the captcha purely in javascript since you could just type the captcha in well before a userscript would be able to fill it out.

I optimised my decoder a bit to pre-calculate the cosine values and skip out the processing of AC values in an MCU if they are all 0 (and so equivalent to the DC value), it now takes 740-900 milliseconds on my PC to decode the recaptcha image, with an average decode time of just under 50% of what it previously was. Uploaded the updated the script on here.

@ShaunF
Wow! Nice job! I took a another look at the code and its very interesting.

@ShaunF
Once again, mind blowing..... It seems like you're a computer! Where did you learn about how JPEG files are stored in data?

A variety of sites I found with google, here are the ones I bookmarked:
http://www.imperialviolet.org/binary/jpeg/ (Just don't try to read the source code if you don't know haskell, it gave me a head ache. Also there are a few mistakes on this page)
http://www.bsdg.org/SWAG/GRAPHICS/0143.PAS.html
http://www.impulseadventure.com/photo/jpeg-huff...
http://en.wikipedia.org/wiki/JPEG

On the recaptcha decoding side I have a basic image dissection algorithm, it's not very accurate yet but I have a few ideas to improve it, here's what it does so far:
http://herecomethelizards.co.uk/recaptcha/test1/ (quite successful)
http://herecomethelizards.co.uk/recaptcha/test2/ (less successful)

When recaptcha is broken, internet spam will grow once again!
Your code is most interesting ShaunF, but oh how evil it can be :P

Nah, just that if he makes it, it proves that such a thing is feasible and someone else would have made it eventually and they will have to think of something harder to crack instead.

Recaptcha isn't the hardest captcha to solve either, they can always be made much much worse. Its just really easy to implement, looks and works good aswell as it helps a good cause instead of just annoying visitors. I think captcha will be usable for long still, but they might have to think of new ways to make the images harder for bots to read.

Try solving this one. :P
http://snowflakejoins.com/grapcha/index

haha, good one! I would be very annoyed if I had to follow a such too often though :P

good idea :)
but should make the circles to random shapes and random already-captcha text

Attacking *image* captcha is a move in the right direction: towards well designed tests of intelligence, judgment and imagination

death to image captcha... and spammers

http://snowflakejoins.com/grapcha/index

actually, i think now it's too easy to solve because the fonts are all the same, and the lines quite isolated from the white background, however it'll be loads better with some minor improvements

@shaunF: I dont know if you're still working on this, but I noticed that reCAPTCHA allows a 1 character flaw. Also it isn't case sensitive and it uses real words/names, so results may be verified using a wordlist (which would propable be pretty large though)

btw, I just read that there's a program that allows userscripts to work on google chrome. since it's the fasters javascript compatible browser out (I think), maybe it'd be worth it to see how your script runs on it?

You're wrong klmdb. reCaptcha gives you two words, one that it knows is correct and one that failed the OCR-scans and they need help with. As long as you get the known word correct you can put almost anything on the unknown word (though it's hard to tell most of the time which is which). If you get the known word correct it assumes that you was right on the unknown as well and ranks it as a possible solution, when enough have gotten the unknown words "correct" and answered the same it's reviewed as a known word.

oh...

:D

if any one whats OmniPage.Professional.v16.0 fully working i can send it them i dont how ever have a fast up load maybe 60kb/s it will be compressed in WinRAR to help with size i dont what out inreturn and i have got it from very good source vrius free cheak it b4 u unrar. just happy to help i came a long this when i was looking for a way to bypass the CAPTCHA in fb games i have a long way to go b4 i can write my own scripts like lots of u do just starting out with scripting and i say better to try scripting with some thing i wont and am going to use every day feel free to point me to any good info i should no about to do with scripting i have and am still googling like mad soking it all up lol.

ps pm me if any one what`s some software thats is hard or you are finding hard to get hold of i can get all most any thing :D

TaKe EaZy

gavouk wrote:
OmniPage.Professional.v16.0

The security restrictions of Greasemonkey make working with this impossible, although, you can probably use another web alteration utility to interact with it.

Has anyone tried the CAPTCHA on Facebook's MouseHunt game?

I'm trying to decode this type of captcha.

http://yfrog.com/171834fc0c73f44d0dp

Any ideas?