IQ, Math Captcha

This is a gem wrapper for tiny captcha in C with no dependencies.

dongsx

Display and verify arcaptcha service captcha

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

API to interact with BrandCAPTCHA http://www.pontamedia.com/en/brandcaptcha/

Generates and verifies ascii art captcha.

Antigate (Decode captcha service) wrapper for Ruby

Easy to use classical captcha for Rails apps

Description of TinyCaptcha.

Simple negative captcha for Rails

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

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

you will get arithmatic sum with answer you just have to compare with ur user in controller

Captcha based on encyrpting and decrypting user data by mathematical operation

Metabypass | Ruby-based easy implementation for solving any type of captcha by Metabypass

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

Integrate the AreYouAHuman.com CAPTCHA alternative human verification into your Ruby/Rails application

Helps humankind with simpler captchas

Form protection with simple captcha calculations.