Captcha based on encyrpting and decrypting user data by mathematical operation

Integrate the AreYouAHuman.com CAPTCHA alternative human verification into your Ruby/Rails application

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

Block repetetive requests from logged_in users and shows captcha.

My version of SimpleCaptcha

This gem enable to use Captchme. Anti spam, Monetize captcha and Audience qualification

Ruby wrapper for Yandex.Cleanweb

Simple negative captcha for Rails

Metabypass | Ruby-based easy implementation for solving any type of captcha by Metabypass

Antigate (Decode captcha service) wrapper for Ruby

A smart captcha library

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

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.

这是一个验证码生成器。基于rucaptcha。本人只是将他的源码拉下来。为我的网站进行适配。因为我不使用sesion.id

Description of RailsCaptcha.

Anti-spam protection for your website

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

Simple captcha image generator gem

Solve Media CAPTCHA Replacement

A gem to generate captcha pictures.