Completely Automated Public Turing test to tell Computers and Humans Apart used in form validation to restrict access to humans only

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5
votes
4answers
3k views

CAPTCHA or email confirmation?

I have read that captcha isn't a perfect solution to protect a website where for example the user can create an account, since there are many people in different countries that practicallty read ...
-5
votes
2answers
1k views

Is it possible to break captcha? [duplicate]

Possible Duplicate: Can a CSRF CAPTCHA be defeated? Is it to possible break captcha? If yes, how? If no, why websites use difficult captcha systems?
2
votes
2answers
161 views

Are these email captchas legitimate?

The last week, I've been getting this kind of emails to addresses that I don't use: Dear Sir, Madam, For security reasons and as part of our ongoing fight against spam, it is our policy not ...
1
vote
1answer
372 views

How reliable/secure is QCaptcha?

QCaptcha is an alternative way to protect a website from bots. It required a drag and drop action like this: Question How reliable is this implementation when compared to others mentioned on ...
3
votes
4answers
2k views

Can a CSRF CAPTCHA be defeated?

One defense that developers use to protect against a CSRF attack is to implement a CAPTCHA in critical steps. A CAPTCHA ensures that a human is at the keyboard approving the activity. But I've ...
5
votes
5answers
1k views

Why re-verify with CAPTCHA on failed form entry?

Is there a reason for sites to ask for another CAPTCHA verification when some other part of the registration form, e.g. the username, was invalid?
9
votes
7answers
1k views

What type of captcha will you recommend?

What type of captcha will you recommend? I am looking mainly at usability, ease of use (development too), relatively secure Usability I find that those captcha with very curly words/numbers are ...
2
votes
5answers
1k views

Anyone using Asirra in production? Are there similar alternatives?

The Asirra project is a Captcha alternative that shows you pictures of kittens and puppies to fend off bots and prove that the end user is a human. Is anyone using Asirra (or something similar) in ...