Comments on: Microsoft Asirra and Inkblot: Are they worth it?

By: Niyaz PK

Niyaz PK — Thu, 26 Jun 2008 07:01:07 +0000

Marcin,
“What irritates me is that I get it right each time and I am still forced to enter it again in the future! They should monitor users that are trusted so that they never have to enter Captcha after their initial visit and registration”
That is true. But the problem is that spammers can exploit this too. It is always a cat-mouse race.

Ralph,
Nobody seriously uses Asirra. So nobody is trying to crack it yet I think.

By: Ralph

Ralph — Mon, 23 Jun 2008 20:15:57 +0000

I don’t think the Asirra image problem (cat vs. dog) would be too difficult to solve. I think a neural network could learn to discriminate between the two in most cases. Granted, doing it 12 times perfectly presents high odds, but still I think there’s a good chance of defeating it.

I almost wonder whether Microsoft wants a system which it can crack but which others assume they cannot.

Has anyone actually seriously tried to break Asirra?

By: James

James — Wed, 18 Jun 2008 20:45:45 +0000

I’m sorry but Marcin, your math is terrible.

If there was only ONE photo of a cat or dog, then the bot would have a 50/50 chance of guessing it right. But if you actually looked at the photo or read the post, there are TWELVE pictures of dogs and cats.

So one picture = 50% guessing correctly, two pictures = 25%, etc, etc. Take that out to all 12 pictures and you end up with over 4000 different combinations. So that means by blindly guessing, the bot has a fraction of a percent of getting it right, NOT a 50% chance.

Do you really think that would make a captcha that easy?

By: Cats and Dogs

Cats and Dogs — Wed, 05 Mar 2008 23:58:26 +0000

[...] Another blogger seems to take a dim view of Asirra, but I think his main criticism (being able to defeat the CAPTCHA by enlisting users of a legitimate site and storing the results keyed to an image hash) is something that could be addressed in several different ways. I thought about cropping and rotating the images, and then, after a brief search, found this paper whose results suggest that those may be viable options to defeat image hashing algorithms. This is definitely another “arms race” situation where spammers will keep developing new techniques to defeat “human authentication,” but I think Asirra is a pretty decent idea, and, like I said earlier, a lot more fun than a traditional CAPTCHA. [...]

By: vijay

vijay — Fri, 04 Jan 2008 12:41:09 +0000

It s funny actually
if this is the case , i wont be able to login to any of my accounts
moods change and so does our thinking

By: Marcin

Marcin — Thu, 03 Jan 2008 07:07:15 +0000

Cat or dog? That means a bot has a 50% chance of entering the website simply by guessing.

Recently I got fed up with the Captcha appearing over-and-over at Yuwie. Every 5 messages I send to friends, I have to enter a Captcha word. What irritates me is that I get it right each time and I am still forced to enter it again in the future! They should monitor users that are trusted so that they never have to enter Captcha after their initial visit and registration. It becomes irritating after a while, and there are already programs that distinguish Captcha phrases faster than humans.

Employ some children. Pay them a few dollars each day. Have them manually go through comments and delete spam. This way give children a decent job (no more lemonade stands) and we don’t anger the frequent website visitors.

By: Techblissonline Dot Com

Techblissonline Dot Com — Tue, 01 Jan 2008 07:29:05 +0000

money getting wasted…

By: Mark

Mark — Mon, 31 Dec 2007 03:10:05 +0000

Great!!! I could’nt agree more.