On Mon, 2007-04-09 at 17:28 +0200, Tijnema ! wrote: > On 4/9/07, Stut <stuttle@xxxxxxxxx> wrote: > > Tijnema ! wrote: > > > On 4/9/07, Robert Cummings <robert@xxxxxxxxxxxxx> wrote: > > >> On Mon, 2007-04-09 at 16:39 +0200, Tijnema ! wrote: > > >> > On 4/9/07, Robert Cummings <robert@xxxxxxxxxxxxx> wrote: > > >> > > On Mon, 2007-04-09 at 16:27 +0200, Tijnema ! wrote: > > >> > > > > > >> > > > I think that we can conclude that a non-crackable CAPTCHA doesn't > > >> > > > exist, but also that there doesn't exist a real "hard to crack" > > >> > > > CAPTCHA. All current CAPTCHAs can be broken quite easy. MD5 can > > >> help > > >> > > > in some cases, but only if the CAPTCHA uses static > > >> > > > images/audio/video/etc. Just about your Audio CAPTCHA, you could > > >> use > > >> > > > MD5 to crack it, as the number has the same MD5 sum each time. > > >> > > > > >> > > Similar methods could be applied to sound as to images to distort the > > >> > > sound enough to make it difficult for speech recognition software to > > >> > > understand, but not so much that real humans couldn't understand > > >> it. At > > >> > > any rate, it could be enough to prevent md5 indexing... but then > > >> again, > > >> > > that would require the audio be mutated on each request, and enough > > >> > > audio be mutated to prevent md5 indexing based on partial > > >> signatures -- > > >> > > similar to how viruses are detected - this is especially important if > > >> > > using dictionary words since the sample space is so small (could > > >> always > > >> > > use sentences though) :) > > >> > > > > >> > > Cheers, > > >> > > Rob. > > >> > > > >> > But well, you can't have a audio only CAPTCHA on your site...., a lot > > >> > people don't have speakers on there PC. And some people can't > > >> > recognize english numbers... > > >> > So then you have an "write the key" CAPTHCA or smiliar on your site, > > >> > and the cracker would use that :) > > >> > > >> Yep, like I said to Tedd before... kinda need multiple forms of captcha > > >> tailored to particular special needs audiences. Visual is good for > > >> pretty much all but the blind. Blind people can use audio captcha. > > >> Beyond that... is it worth the cost to target diminishing audiences? > > >> > > >> Cheers, > > >> Rob. > > > > > > Uhm, blind people can't even view your page :P > > > I think you mean visual impaired people :) > > > > Yes they can... http://www.webaim.org/articles/visual/blind.php > > > > -Stut > > Interesting... Didn't know that... :) By blind though I meant both visually impaired and as Stut pointed out for you, completely blind :) They sort of need the same solution unless the visual impairment is minor. Cheers, Rob. -- .------------------------------------------------------------. | InterJinn Application Framework - http://www.interjinn.com | :------------------------------------------------------------: | An application and templating framework for PHP. Boasting | | a powerful, scalable system for accessing system services | | such as forms, properties, sessions, and caches. InterJinn | | also provides an extremely flexible architecture for | | creating re-usable components quickly and easily. | `------------------------------------------------------------' -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
