Simple Audio Extension to Simple Captcha

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

Gem that uses RuCaptcha API to solver any type of captcha

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

Captcha Client for YunPian.com

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

Simple captcha based on plain text questions.

A simple image captcha gem

RedisCaptcha provides simple captcha that can be read by human.

generate captcha by dalli,use the memcache

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...

Rack middleware Captcha verification using Recaptcha API.

BrainBuster - a logic captcha for Rails

ActsAsTextcaptcha provides spam protection for Rails models with text-based logic question captchas. Questions are fetched from Rob Tuley's textcaptcha.com They can be solved easily by humans but are tough for robots to crack.

Despamilator is a plugin based spam detector designed for use on your web forms borne out of two annoyances: Spam being submitted in my web forms and CAPTCHAS being intrusive. Despamilator will apply some commonly used heuristics from the world of anti-spam to help you decide whether your users a...

Arithmetic Captcha

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

RubyGem package for visualCaptcha's backend service

Quick little arithmetic plain-text captcha