Ruby wrapper for Yandex.Cleanweb

generate captcha by dalli,use the memcache

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

A gem to generate captcha pictures.

simple stupid captcha

Captcha based on encyrpting and decrypting user data by mathematical operation

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.

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

IQ, Math Captcha

MVC based Math, Logic Captcha

Quick little arithmetic plain-text captcha

Forked from https://github.com/kares/simple_captcha

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

RMagickCaptcha is a gem that implements captcha for using in Rails application.

Simple, easy captcha for Sinatra

Solve Media CAPTCHA Replacement

A very simple rack captcha middleware via captchator.com API

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

Gem that uses RuCaptcha API to solver any type of captcha

RedisCaptcha provides simple captcha that can be read by human.