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

NO LONGER MAINTAINED AND NOT RECOMMENDED, AS BOTS ARE ABLE TO RESOLVE CAPTCHAS BETTER THAN HUMANS.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.

dongsx

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

A simple image captcha gem

Captcha based on encyrpting and decrypting user data by mathematical operation

Gem that uses RuCaptcha API to solver any type of captcha

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

My version of SimpleCaptcha

Quick little arithmetic plain-text captcha

create captcha for api based project

Repackaged visualCaptcha's backend service, including translation and minor modification. Mainly for private use. Everything still belongs to original author: emotionLoop. ...

Death by Captcha Ruby implementation (HTTP API)

MVC based Math, Logic Captcha

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

A smart captcha library

Merb plugin that provides resource access rate limits and captcha'ing

Description of TinyCaptcha.

Simple, easy captcha for Sinatra

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.