Exactly. Just like their visual counterparts, audio captchas are
obfuscated to resist cracking by voice recognition. I know one of the
guys who did one of the voices for AOL's captcha and they had to make it
tougher to keep out the hackers. Hence a random mix of letters and
numbers with different voices and background noise. As I mentioned
before, it's an arms race. As the algorithms of the bad guys get better
the cognitive load required to understand the captcha will rise to the
point where regular folks won't be able to pass the test. Turing would
be impressed.
While we could switch to some other tests they would have to be
sufficiently complex to fool an algorithm while simple enough that a
real human being can solve them and not necessarily require English as a
first language. I haven't seen another better solution yet. There are
some visual ones with random photos and letters where you have to
identify which one is a cat or whatever, but that's not really accessible.
CB
Jayson Smith wrote:
Some more observations...
On my Windows machine, I acted like I was trying to sign up for a
new account, and it gave me the old-style audio captcha. I went to
post, but don't actually have anything real to post, so didn't go
through with it, so don't know what I'd have gotten.
As for the old audio captcha, assuming it's gone, I'd be surprised
if they go back to it. As I pointed out earlier, the phonetic words
they used are very well known world-wide. I'm sure these very words
were specifically designed so that any one of them can be
distinguished from any other word in that set, E.G. during a radio
transmission in less than optimal signal conditions. Probably pretty
easy for a voice recognition system to crack that.
Jayson
----- Original Message ----- From: "Tiffany D" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Wednesday, June 18, 2008 6:48 PM
Subject: Please Join Me In Making Craigslist Accessible Again
*Please pass this onto any groups or individuals you think could help.
This is serious.
*
Hello to all,
As most of you know by now, many sites use capcha for making posts
etc. Craigslist was always one of the best in this regard. Their
audio was clear and clean, even employing words for letters (a, as in
alpha) to make understanding the codes easier. However, I just logged
in today and when I tried to make a post, I noticed that it didn't
work at all on my Macbook. When I tried posting with my Windows XP
computer, I discovered that their formatting has changed. Not only is
their an extra step to post, but the audio capcha is now similar to
AOL, with many voices speaking at once and it's very difficult to hear
the actual letters in the capcha. I propose creating a petition, to
be signed by all blind and visually-impaired people, as well as other
concerned parties, asking Craigslist to return the capcha to it's
former state and to once again make it Mac and VoiceOver accessible.
While I was posting an add for my personal use, my job also relies
heavily on Craigslist to generate ads and I'm clearly not the only
blind individual using it for this purpose. Please join me in this
effort. The changes are extremely recent and we may be able to stop
this before it becomes permanent.
Thank you,
Tiffany Dunn
