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

adds audio support to simple captcha

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

Captcha generator for rails

Simple captcha

create captcha for api based project

Simple captcha image generator gem

A captcha that uses images instead of garbled text

Implementation of captcha (Completely Automated Public Turing-Test to Tell Computers and Humans Apart) that is both easy to use and easy to customize/extend.

Solve Media CAPTCHA Replacement

jQuery slide captcha system with jQuery & jQuery UI for Rails 3

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.

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

Easy to use classical captcha for Rails apps

A gem to generate captcha pictures.

Form protection with simple captcha calculations.

Helps humankind with simpler captchas

HumanDetector is a friendly logic captcha for Rails the doesn't require any external system dependency (e.g. external captcha API connections). It uses a simple question that any 7 or more years old human can understand, but that a spambot will not be able to answer. This Gem supports Ruby v1.9.2...

Generates and verifies ascii art captcha.

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