Simple gem to add captcha or negative captcha to your Rails 3 application

ALTCHA is a free, open-source CAPTCHA alternative that protects your website from spam and abuse

This is a Captcha gem for ruby. It drawing captcha image with C code so it no dependencies.

It's a Rails Captcha Engine for Rails 3 applications.

Simple reverse captcha solution that consist in create a hidden field that should be always empty.

Block repetetive requests from logged_in users and shows captcha.

Unity Captcha is a gem that use two levels of Captcha. First level is about Left Hemisphere: Logic and Math. Second level is about Right Hemisphere: Intuition and Drawing. This two levels functioning in complete harmony creates unity and this is the base design of this Captcha.

Due to many unrequited complaints to the recaptcha team with regard to its unreadability for real human users, this gem offers a more readable selection of captcha images.

To help with keep the bots at bay this gem helps you easily add honeypots to forms and/or obfuscate your form field names

Captcha Client for YunPian.com

anti-captcha is a Ruby library for recognize captcha on anti-captcha.com

adds audio support to simple captcha

A simple and custom captcha for Rails3.

LoyalSimpleCaptcha is available to be used with Rails 3 or above and also it provides the backward compatibility with previous versions of Rails.

This is a Captcha gem for Rails Applications. It drawing captcha image with C code so it no dependencies.

Captcha form Jike API

SoaringSimpleCaptcha is available to be used with Rails 3 or above and also it provides the backward compatibility with previous versions of Rails.

Wrapper for Captchabot.com

API to interact with BrandCAPTCHA http://www.pontamedia.com/en/brandcaptcha/

Implements view helpers for the ASIRRA CAPTCHA system for Rails-based websites