Simple, easy captcha for Sinatra

A very simple rack captcha middleware via captchator.com API

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

RedisCaptcha provides simple captcha that can be read by human.

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

My version of SimpleCaptcha

Captcha based on encyrpting and decrypting user data by mathematical operation

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

Description of RailsCaptcha.

create captcha for api based project

Captcha based on encyrpting and decrypting user data by mathematical operation

NO LONGER MAINTAINED AND NOT RECOMMENDED, AS BOTS ARE ABLE TO RESOLVE CAPTCHAS BETTER THAN HUMANS.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

This plugin adds helpers for the YinXiangMa CAPTCHA API

Quick little arithmetic plain-text captcha

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

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...

Simple captcha image generator gem

A captcha verification approach for Rails apps, directly integrated into ActiveRecord’s validation mechanism and providing helpers for ActionController and ActionView.