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Yahoo CAPTCHA Cracked.

0x000000.com

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Re: Yahoo CAPTCHA Cracked.

#11

Post by utnick »

marcus wrote: post #5
ajkirwin wrote: post #2

A long time ago I decided, that if I were to ever have a captcha system, it wouldn't use ones of that style, which are getting so.. randomized these days, it's hard for a human to read. Frankly, I think knowledge or logic based captchas are the way to go. "Todd is three times as old as Jane is. When Jane was ten years younger, Todd was five times as old as Jane is. How old is Todd?" for example. Sure, takes longer to…

I'd take you on that bet. Write the system and I'll write the solver. I drink Guinness :) A better system would be to ask the user to identify the gender of a person based on an image to tell whether the picture is of a dog or of a cat and so on, these tasks are trivial for a person and very very hard for a program.

i could write a script to solve your system 50% of the time, which is probably good enough for spammers

Re: Yahoo CAPTCHA Cracked.

#12

Post by apgwoz »

marcus wrote: post #9
apgwoz wrote: post #7

Earlier quoted context omitted.

My introduction to AI class required us to write a classifier for people in the news (20 different images of 10 different people). We were given the location of the people's faces, but we were able to get 60% accuracy using SVMs and the 32x32 block of pixels (nose, eyes, mouth region). This was the "baseline" system. Some systems were getting nearly 85+%. I must admit though, that this was a restricted dataset, but t…

You are confusing two different tasks, identifying a person out of a small comparison group is relatively easy - just deconstruct the face & compare certain facial features. There was a ton of research on the subject and even some working commercial products (my schools AI lab uses one we built as a lock). Identifying gender is significantly harder. You want something a lot harder, have them click on the picture of t…

I don't see why it'd be harder with good features, and after looking at the article again, 35% accuracy was considered a success. Obviously, I'm not as qualified as you in this sense, but it seems logical based on results I've seen (again, admittedly not the same quality as you've probably seen).

Re: Yahoo CAPTCHA Cracked.

#13

Post by hhm »

apgwoz wrote: post #12
marcus wrote: post #9

Earlier quoted context omitted.

You are confusing two different tasks, identifying a person out of a small comparison group is relatively easy - just deconstruct the face & compare certain facial features. There was a ton of research on the subject and even some working commercial products (my schools AI lab uses one we built as a lock). Identifying gender is significantly harder. You want something a lot harder, have them click on the picture of t…

I don't see why it'd be harder with good features, and after looking at the article again, 35% accuracy was considered a success. Obviously, I'm not as qualified as you in this sense, but it seems logical based on results I've seen (again, admittedly not the same quality as you've probably seen).

I checked on the "obviously, I'm not as qualified as you in this sense" by looking at the user info, and I remembered that "Ideas to monetize new artifical intelligence" thread... so Marcus, sorry if it's offtopic, but how did you solve that problem? Are you doing captchas maybe? :)

Re: Yahoo CAPTCHA Cracked.

#14

Post by marcus »

hhm wrote: post #13
apgwoz wrote: post #12

Earlier quoted context omitted.

I don't see why it'd be harder with good features, and after looking at the article again, 35% accuracy was considered a success. Obviously, I'm not as qualified as you in this sense, but it seems logical based on results I've seen (again, admittedly not the same quality as you've probably seen).

I checked on the "obviously, I'm not as qualified as you in this sense" by looking at the user info, and I remembered that "Ideas to monetize new artifical intelligence" thread... so Marcus, sorry if it's offtopic, but how did you solve that problem? Are you doing captchas maybe? :)

Doing CAD - Computer Assisted Diagnosis - working on improving early cancer detection in Mammography.

Re: Yahoo CAPTCHA Cracked.

#15

Post by bayareaguy »

ajkirwin wrote: post #2

A long time ago I decided, that if I were to ever have a captcha system, it wouldn't use ones of that style, which are getting so.. randomized these days, it's hard for a human to read. Frankly, I think knowledge or logic based captchas are the way to go. "Todd is three times as old as Jane is. When Jane was ten years younger, Todd was five times as old as Jane is. How old is Todd?" for example. Sure, takes longer to…

I've always thought that for blog comments, the captcha should actually take the form of a few short SAT-style questions which would test reading comprehension. E.g.

"Which one of the following is not one of the points the author is trying to make"

"Which of the following best describes the authors' opinion of Java?"

"What did the author cite as his source for his labor statistics?"

Re: Yahoo CAPTCHA Cracked.

#17

Post by marcus »

utnick wrote: post #11
marcus wrote: post #5

Earlier quoted context omitted.

I'd take you on that bet. Write the system and I'll write the solver. I drink Guinness :) A better system would be to ask the user to identify the gender of a person based on an image to tell whether the picture is of a dog or of a cat and so on, these tasks are trivial for a person and very very hard for a program.

i could write a script to solve your system 50% of the time, which is probably good enough for spammers

I didn't say you would only have to describe one picture. Make it 16 pictures and you got 1/64k to succeed.

Re: Yahoo CAPTCHA Cracked.

#18

Post by nickb »

dawnerd wrote: post #16

I really like to use reCpatcha. Sure it's not the most secure, but it's for a good cause, and it keeps out the basic bots. For anyone who doesn't know what recaptcha is: http://recaptcha.net/

I wrote about reCaptcha before and the big problem with it is that it can be hard. And by hard I mean that the majority of people can't solve it. If you have a big site and you have a spam issue, then by all means, use it. But if you're a small site that's trying to grow and a site that considers every potential user to be precious, stay away from it because the last thing you want is to frustrate people!

Since you will not be a target early on, consider not using captcha at all since spammers don't target sites that have no traffic.

Re: Yahoo CAPTCHA Cracked.

#19

Post by thomasswift »

nickb wrote: post #18
dawnerd wrote: post #16

I really like to use reCpatcha. Sure it's not the most secure, but it's for a good cause, and it keeps out the basic bots. For anyone who doesn't know what recaptcha is: http://recaptcha.net/

I wrote about reCaptcha before and the big problem with it is that it can be hard. And by hard I mean that the majority of people can't solve it. If you have a big site and you have a spam issue, then by all means, use it. But if you're a small site that's trying to grow and a site that considers every potential user to be precious, stay away from it because the last thing you want is to frustrate people! Since you w…

do you have a link? i love to read your thoughts. I have been thinking about using recaptcha, primarily because of the little refresh button and of course the captcha.

Re: Yahoo CAPTCHA Cracked.

#20

Post by curi »

nickb wrote: post #18
dawnerd wrote: post #16

I really like to use reCpatcha. Sure it's not the most secure, but it's for a good cause, and it keeps out the basic bots. For anyone who doesn't know what recaptcha is: http://recaptcha.net/

I wrote about reCaptcha before and the big problem with it is that it can be hard. And by hard I mean that the majority of people can't solve it. If you have a big site and you have a spam issue, then by all means, use it. But if you're a small site that's trying to grow and a site that considers every potential user to be precious, stay away from it because the last thing you want is to frustrate people! Since you w…

comment spammers came to my blog. which has no traffic.
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