Most effective form of CAPTCHA?

Question

Of all the forms of CAPTCHA available, which one is the \"least crackable\" while remaining fairly human readable?

Answer 1

Here is a cool link to create CAPTCHA..... http://www.codeproject.com/aspnet/CaptchaImage.asp

Answer 2

Death by Captcha can solve any Regular CAPTCHA (incude reCAPTCHA), but not Speedcoin Cryptocurrency Captcha.

Death by Captcha - http://deathbycaptcha.com

Speedcoin Captcha - http://speedcoin.co/info/captcha/Speedcoin_Captcha.html

Answer 3

I agree with Thomas. Captcha is on its way out. But if you must use it, reCAPTCHA is a pretty good provider with a simple API.

Answer 4

CAPTCHAS, I believe should start being considered heavily when designing the UX. They're slow, cumbersome, and a very poor user experience. They are useful, don't get me wrong but perhaps you should look into designing a honeypot.

A honeypot is created by adding a hiddenfield at the bottom of the form. Because spam bots will fill in all the fields on the page blindly you can do a check:

If honeypotfield <> Empty Then
   "No Spam TY"
Else 
    //Proceed with the form 
End If

This works until there is a specifically designed spambot for your site, so they can choose to fill out selected input fields.

For more information: http://haacked.com/archive/2007/09/11/honeypot-captcha.aspx/

Answer 5

This information is hard to really know because I believe a CAPTCHA gets broken long before anybody knows about it. There is economic incentive for those that break them to keep it quiet.

I used to work with a guy whose job revolved mostly around breaking CAPTCHA's and I can tell you the one giving them fits currently is reCAPTCHA.

Now, does that mean it will forever, call me skeptical.

Answer 6

I believe that CAPTCHA is dying. If someone really wants to break it, it will be broken. I read (somewhere, don't remember where) about a site that gave you free porn in exchange for answering CAPTCHAs to they can be rendered obsolete by bots. So, why bother?