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

Solve Media CAPTCHA Replacement

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

My version of SimpleCaptcha

Simple, easy captcha for Sinatra

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

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

This version include two important page 'Contact' and 'Register' with the 'Math-Captcha' method submit for prevent hacker attack.

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...

MVC based Math, Logic Captcha

IQ, Math Captcha

A simple image captcha gem

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

dongsx

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.

Death by Captcha Ruby implementation (HTTP API)

Form protection with simple captcha calculations.

Captcha based on encyrpting and decrypting user data by mathematical operation