KeyCAPTCHA does not work? I tried several times to install the plugin KeyCAPTCHA unsuccessfully using the K2 system registry, uninstalled only when it works together with ReCAPTCHA. At the site of Joomla extensions one reviewer said you sent one solution to this problem could share?

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I've been using KeyCaptcha on other products since it basically hit the market, and it is seriously the first captcha que product can not be cracked. Recapthca is a waste of time, as it was cracked long August I had to contact support about K2 integration comment, They sent me an additional add-on to cater it, and Within the team my entire site was open and free to the public, protected, knowing this can not be cracked. Human spam will always exist, but this makes even annoying que When an IP is used too much for registration. Extremely clever system.

extensions.joomla.org/extensions/access-a-security/site-security/captcha/18364

KeyCaptcha blocks too many quite legitimate users

Hello I think you are reffering to this post.
getk2.org/community/New-to-K2-Ask-here-first/178453-HOW-TO-Captcha-other-than-recaptcha

Thanks for the support! I'm using PlayThru in place of KeyCAPTCHA now.

You can always give Akismet a try as well. K2's latest version offers Akismet integration