A captcha verification approach for Rails apps, directly integrated into ActiveRecord’s validation mechanism and providing helpers for ActionController and ActionView.

Simple, easy captcha for Sinatra

Simple captcha image generator gem

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

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

Death by Captcha Ruby implementation (HTTP API)

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

Simple lib to generate a math_captcha to prevent spammers in form. Supports localization.

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

NO LONGER MAINTAINED AND NOT RECOMMENDED, AS BOTS ARE ABLE TO RESOLVE CAPTCHAS BETTER THAN HUMANS. Based on Login Attempts check if captcha is necessary. It stores a permanent cookie and uses a table for tracking login requests.

Description of TinyCaptcha.

Gem that uses RuCaptcha API to solver any type of captcha

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

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.

A very simple rack captcha middleware via captchator.com API

This is a gem wrapper for tiny captcha in C with no dependencies.

This library can help you create a captcha in your terminal application, which may be damaged by a large influx of requests.

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

Description of RailsCaptcha.