|
|
Posted by Philip Baker on 02/25/07 23:11
In article <87wt2825q7.fsf@dinopsis.dur.ac.uk>, Chris Morris
<c.i.morris@durham.ac.uk> writes
>Harlan Messinger <hmessinger.removethis@comcast.net> writes:
>> David E. Ross wrote:
>> > If you use a CAPTCHA, be sure to provide for the visually handicapped
>> > who might be using an audio browser. CAPTCHAs even create problems for
>> > the dyslexic and colorblind.
>>
>> They can even create problems for normally sighted people without
>> perceptual disabilities. Oftentimes I have been unable to tell whether
>> a particular stroke was part of a letter or part of the obfuscation.
>
>Unfortunately for CAPTCHAs, image processing software is able to
>defeat any capture that might be easy for a person to read... The
>eventual consequence will be CAPTCHAs that no-one can read.
>
>Of course, the reason they're a bad idea is encoded into their name. A
>Turing test is where a human tries to distinguish between a human and
>a computer. Since no computer program has passed the test, no computer
>program is qualified to administer the test by definition... (and even
>then it'd be the wrong test - automatic isn't necessarily spam, manual
>isn't necessarily not spam)
>
>Conversely, a very simply written spamfilter will catch >99.9% of
>spam. It's nowhere near as complex a problem as email spam. The big
>giveaway is unexpected URL markup in the content, but adding a few
>other regex-based tests helps.
>
That is the obvious solution for 99.9% of cases and so far I have found
it effective. It is the big sites that have the real problem. For
instance Yahoo, that want to block the automated creation of thousands
of accounts which can then be used for nefarious purposes like spamming
Yahoo Groups. What besides CAPTCHA can these sites use?
Day by day I'm getting more depressed with the Internet which seems to
be sinking in a swamp of spam. All the methods being used against it are
just fire-fighting and not getting to the root of the problem.
--
Philip Baker
PJB Software
Thalasson Web Resources
Navigation:
[Reply to this message]
|