Simple, easy captcha for Sinatra

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...

adds audio support to simple captcha

Gem that uses RuCaptcha API to solver any type of captcha

Captcha form Jike API

simple stupid captcha

A simple image captcha gem

generate captcha by dalli,use the memcache

A simple and custom captcha for Rails3.

MVC based Math, Logic Captcha

Rack middleware Captcha verification using Recaptcha API.

BrainBuster - a logic captcha for Rails

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...

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.

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

Russian Post tracking toolset, consisting tracking form bot (since Russian Post is too retarded for normal API) and captcha solver/recognizer.

Quick little arithmetic plain-text captcha