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Questions tagged [captcha]

CAPTCHA is a program that protects websites against bots by generating and grading tests that humans can pass but current computer programs cannot.

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How can robots beat CAPTCHAs?

I have a website e-mail form. I use a custom CAPTCHA to prevent spam from robots. Despite this, I still get spam. Why? How do robots beat the CAPTCHA? Do they use some kind of advanced OCR or just get the solution from where it is stored? How…
totymedli
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Are captchas worth the decreased usability?

When is it useful to use a captcha? When is it an unnecessary hindrance? Is a captcha just a quick fix for the lazy/unexperienced programmer, or are they really the best way to prevent spam and bots?
Atomix
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A new CAPTCHA using sentences?

I was just thinking about how recaptcha is getting harder when I thought about another posible solution. Images won't last forever so we will need something else some day - like human logic or emotion. Google and others are trying grouping images by…
Xeoncross
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Best practices to avoid fake profiles?

When offering to create a profile (for example, login+pwd) for a web service, what are the best practices one should implement to avoid mass spamming/creation of fake profiles? I am thinking about email confirmation, captchas, etc... any other ideas…
Jérôme Verstrynge
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Idea for CAPTCHA

CAPTCHAs have a lot of downsides, accessibility and user friendliness are two things that are often sacrificed. I've thought of an idea that might work really well, has this ever been attempted before? Prerequisites The prerequisite for it is that…
Tom
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Are sessions secure for captcha on failed login?

I don't like writing open-ended questions but I have a quick security question. I have a PHP login script that shows a CAPTCHA on the third failed login attempts. The way I'm counting failed logins is by using session data. Is this secure? Is there…
Brooke.
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How can a CAPTCHA be integrated into a community?

I'm planning on making a simple discussion feature for a web framework I'm building. It should: allow anonymous posting block spam bots The obvious answer is to use a generic "captcha" plugin, however I think there are some creative…
Edward Tanguay
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JS Captcha in contact form validation to avoid spam bots

I am looking for opinions about how bulletproof could his captcha system be to avoid spam in a contact form. The form submit goes through ajax. So I generate 2 random numbers with javascript. The sum of those numbers must be correct. On form…
kosmosan
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How is it possible that facial recognition software can work, but a reCAPTCHA can't be solved by a computer

If software can be built to recognize faces and match those faces to names, then how is that CAPTCHA works? Recognizing letters seems a lot easier than matching faces.
Ryan
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