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

A simple and custom captcha for Rails3.

Submit captcha images and retrieve the text as a string.

Rails mountable engine, that provides captcha support

A simple and fast image captcha generator that uses opencv and memcached.

A captcha that uses images instead of garbled text

A honeypot style captcha extension for ActiveRecord. Simple one-line inclusion in the model combined with a simple form field should trap the bad guys in the molasses.

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.

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

A gem to generate captcha pictures.

simple stupid captcha

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

generate captcha by dalli,use the memcache

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

Display and verify arcaptcha service captcha

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

A simple way to add zero friction captchas to Rails forms

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