Captchas

Did you read that thread?

[henry0]

Captchas obsolete? [webmasterworld.com]

jk has a good point: Do not rely on a single technique, set many strong bastions!

[eelixduppy]

Indeed, always go with multiple checks in case one of them fails.

Captchas aren't dead, just instead of changing the method many developers insist on staying with the original ideas and making them more complex, which makes it harder for humans to use. In my opinion, we have to move away from changing the complexity level to fool computers and come up with different solutions altogether. There are tons of differences between how computers 'think' and how humans think--we start here.

[henry0]

For example a simple quiz (image based sounds better than textual) could be quite powerful.
Could be preset with tons of options/answers and randomized.

I have an idea: Asking to type the name of a simple color swatch, I do not think that spammers could
analyse the color of for examole a 20*20px rectangle filed with a basic color and come with its name.

Perhaps I should have kept it for my own usage :)

[eelixduppy]

It might be easier than you think to identify a basic color. Using php's GD functions alone I think I can pull it off. The one good thing about it, however, is that someone would have to write the code specific to your site to bypass it.

[Marshall]

20*20px rectangle filed with a basic color

Would this not present a problem for someone who is color blind?

Marshall

[eelixduppy]

>> Would this not present a problem for someone who is color blind?

That is very true, too. Whatever validation is used it must be usable by the users visiting the site.