Twokinds ARCHIVE Forums

Since it seems that more and more bots are getting in every day I thought that I'd start working on my own Captcha project. I currently have 2 randomization styles made for it and hope to make more soon.
Here is a link to the page: http://69.141.241.56:8080/captcha_kitsune.php

Let me know if you guys have trouble reading them or if you noticed any possible weaknesses in them. I'd also love to hear or see any ideas for more styles to mix it up with.

I like that one better. Easy to see.

It's still somewhat vulnerable to the blur/contrast trick, however this time I had problems with the borders (they are lighter).

Thus my suggestion is to add more variety in the 'white/black' ratio. Like so:

(I used some cheap blurring to achieve this, perhaps with your method you can make part of the algorithm)

(The blob overlay used to modify your image was created by making a layer with random colors,emboss it, scale immensely with interpolation (you can scale in multiple steps, I went from 420;125 to 5000;5000), set layer to multiply mode, then fiddle around with brightness.

Say.. If these were really used, would they still be this size? Not that it really matters, but it's kinda big.

And if they were to be resized, would they still be as readable?

Don't worry, , I find that easy to read :P



EDIT:
Very interesting to read:
http://network-security-research.blogspot.com/

Here's an idea, I suppose it might have been suggested before, but it's simple: Put more text in the image than you want the user to use. Have, say, 3 lines of numbers, and the captcha instructions tell the user to use only the middle line. It would be broken after a while, but it would throw off most bots because they'd use all of the numbers by mistake.

I can't read it when it's that small. The "I" looks like a 1, l, or I to me.

You mean something like this?

"The more difficult version of the Gimpy CAPTCHA presents an image such as the one shown below. There are 10 words (some repeated), overlaid in pairs. The test-taker is required to list 3 of the words present in the image in order to pass. "
Source: http://www.cs.sfu.ca/~mori/research/gimpy/


Heh, yeah, I guess it was easy for me since I've been looking at those letters the whole time...

Also, other captcha's have the same problem. Usually the only include I and never show l or 1 to avoid confusion.

I can only see a "t" an "x" and a "u" in that.....

hey everyone, i've added another style that has a checkered background for the image and I want to know what your opinions on it are.

http://69.141.241.56:8080/captcha_kitsune.php

The checkered one is bad for the eyes (mine at least). The others are fine for humans, but I haven't got a clue on how bot proof they'd be.

Also, since you're using a regular background it's easy to track it. Then by looking where in the picture the pattern isn't followed we know that it must be part of a character:


With the usual blur;contrast/brightness this is the result:


Have you checked out the link I posted earlier?
http://network-security-research.blogspot.com/

Yes i had a look at that link, I'll see about a different version of the second set to replace the third.