adds audio support to simple captcha

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

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

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

A very simple rack captcha middleware via captchator.com API

It's a Rails Captcha Engine for Rails 3 applications.

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

Simple reverse captcha solution that consist in create a hidden field that should be always empty.

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 port of VIT AutoCaptcha

wxianfeng_simple_captcha is captcha for rails,modified from simple_captcha .

Ruby wrapper for Yandex.Cleanweb

Unity Captcha is a gem that use two levels of Captcha. First level is about Left Hemisphere: Logic and Math. Second level is about Right Hemisphere: Intuition and Drawing. This two levels functioning in complete harmony creates unity and this is the base design of this Captcha.

A simple CAPTCHA implementation for Rails 5+ based on RMagick.

A gem to generate captcha pictures.

Due to many unrequited complaints to the recaptcha team with regard to its unreadability for real human users, this gem offers a more readable selection of captcha images.

NO LONGER MAINTAINED AND NOT RECOMMENDED, AS BOTS ARE ABLE TO RESOLVE CAPTCHAS BETTER THAN HUMANS.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