At 7:54 PM +0200 4/5/07, Tijnema ! wrote:
About your dot-captcha program tedd, it's another trick, it hasn't
been used yet, so somebody needs to look at it to crack. Like Jochem
said, if someone really wants to break it, he will do it. Making a
real though CAPTCHA isn't that hard, it's hard to create a CAPTCHA
that's easy to the user, but very hard to bots.
I realize that no captcha will be 100 percent successful in keeping
spammy out for if it was then spammy would hire cheap human help to
defeat them. However, that's more expensive than a bots and I like
making spammy's job harder and more expensive.
Side note -- I've actually had spammy single me out and do all sorts
of nasty stuff, so my efforts are not going unnoticed.
I was thinking about animation, very simple like a moving dot. "Did it
move from left to right, right to left, top to bottom or bottom to
top?"
What about the dyslexic?
I had a similar idea in that I would present a string like "A7F3"
where I would ask "Please enter the second character from the left."
Unfortunately, those who are dyslexic would have problems with that.
As animated images/flash/movies are really though items to parse for a
bot. So just creating an AVI made up from a few simple frames.
Everyone can see if which side the dot moves. But yet, there's no
movie support in PHP, i discussed this on the internals list, but
nobody seems interested, and this is the case i need it again :).
For animated images, I use gifs (like a spinning wait gif). Your idea
could be done with that, but again asking someone which way the dot
moves is not accessible -- it even narrows the numbers for the
sighted group.
I was thinking about creating random frames from PHP(also a random
number, with different frame rates) and then creating an movie from
that frames. I prefer no compression then, because that would require
the user to install decoders. I think these days every user has a
browser supporting inline movies right?
I know, this wouldn't stop the semi-automatic bots, but i think these
are very hard to stop. (Unstoppable maybe?)
Php animation could be done via ajax. You need to have something on
the user's side to communicate when to run each php frame. This is
similar to trying to write a php progress bar for up/down-loading --
it's a question of communication and timing.
Cheers,
tedd
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