IQ, Math Captcha

A simple and fast image captcha generator that uses opencv and memcached.

Quick little arithmetic plain-text captcha

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

Description of RailsCaptcha.

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

A captcha that uses images instead of garbled text

Define questions and answers in a YAML file and validate your models with a single line of code. No more captchas or other stupid tricks.

A honeypot style captcha extension for ActiveRecord. Simple one-line inclusion in the model combined with a simple form field should trap the bad guys in the molasses.

Generates Text Catpchas, that are 'nice' by my own personal definition!

ALTCHA is a free, open-source CAPTCHA alternative that protects your website from spam and abuse

Block repetetive requests from logged_in users and shows captcha.

My version of SimpleCaptcha

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

Ruby wrapper for Yandex.Cleanweb

SimpleCaptcha is available to be used with Rails 3 + 4 or above and also it provides the backward compatibility with previous versions of Rails.

To help with keep the bots at bay this gem helps you easily add honeypots to forms and/or obfuscate your form field names

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