brainbuster 提供问题形式的验证方式Captcha

问题和答案

1, 'What is two plus two?', '4'

为什么不是four?


2, 'What is the number before twelve?', '11'
3, 'Five times two is what?', '10'
4, 'Insert the next number in this sequence: 10, 11, 12, 13, 14, ??', '15'
5, 'What is five times five?', '25'
6, 'Ten divided by two is what?', '5'
7, 'What day comes after Monday?', 'tuesday'
8, 'What is the last month of the year?', 'december'
9, 'How many minutes are in an hour?', '60'
10, 'Spell the word 'dog' backwards.', 'god'
11, 'What is the opposite of down?', 'up'
12, 'What is the opposite of north?', 'south'
13, 'What is the opposite of bad?', 'good'
14, 'Complete the following: 'Jack and Jill went up the ???', 'hill'
15, 'What is 4 times four?', '16'
16, 'What number comes after 20?', '21'
17, 'What month comes before July?', 'june'
18, 'What is fifteen divided by three?', '5'
19, 'Who was the first president of the United States (last name only) ?', 'washington'
20, 'What is 14 minus 4?', '10'
21, 'What comes next? 'Monday Tuesday Wednesday ?????'', 'thursday'

***********************************

缺点显而易见

--题库太小，被攻击的可能性大

--答案可能多元化，4 和four 之类的，系统只能接受4

http://www.plentyofcode.com/2007/07/prevent-robots-from-submitting-data.html

各种语言的Captcha实现，阻止垃圾机器提交




ASP.NET
http://www.15seconds.com/issue/040202.htm
http://www.codeproject.com/aspnet/CaptchaControl.asp
http://www.codeproject.com/aspnet/CaptchaImage.asp
http://www.codeproject.com/aspnet/CaptchaNET_2.asp
http://www.codeproject.com/aspnet/CaptchaLIKE.asp

Java
http://simplecaptcha.sourceforge.net/
http://jcaptcha.sourceforge.net/
http://www.ansir.ca/newsletters/volume5.jsp

PHP
http://www.white-hat-web-design.co.uk/articles/php-captcha.php
http://www.puremango.co.uk/cm_php_captcha_script_113.php
http://www.phpclasses.org/browse/package/2487.html
http://www.codewalkers.com/c/a/Miscellaneous/Creating-a-CAPTCHA-with-PHP/
http://milki.erphesfurt.de/captcha/
http://www.webcheatsheet.com/php/create_captcha_protection.php

Rails
http://www.busyashell.com/blog/articles/2006/07/06/rails-captcha-validation-with-javascript
http://www.rubyonrailsblog.com/articles/2006/09/29/use-the-ruby-captcha-gem-for-rails-user-registration
http://captchator.com/
http://ajaxonrails.wordpress.com/2006/10/24/captcha-in-ruby-on-rails-customize-the-use-of-captcha-in-the-plugin-validates_captcha/

Posted by Bayar at 7:56 AM

不管怎样 nice job！ 后面就是如何完善的事了

http://www.codinghorror.com/blog/archives/001001.html

CAPTCHA 不是完美的，被攻破的可能性始终存在

以后做垃圾广告的也要学人工智能了.

http://recaptcha.net/

reCAPTCHA 免费的 Web service

上火车

http://deadprogrammersociety.blogspot.com/2008/02/recaptcha-on-rails.html

brain_buster 0.8.0 released

好久没有更新了，这回removed all deprecated code, updated for Rails 2.0,

improved specs considerably, and cleaned up the api and views.

http://expressica.com/simple_captcha/

http://expressica.com/2008/09/14/coming-up-simple-captcha-two-point-o/

Coming Up : Simple Captcha 2.0

有的时候，我真的看不清楚图片上写的是啥字母，斜着脑袋看了很久也认不出～～

哈哈，特别是Google的验证，跟画符似的

http://therailworld.com/posts/11-Less-Reverse-Captcha

让人休息

让机器证明它是机

http://github.com/stevenbristol/less-reverse-captcha/tree/master

The Less Reverse Capchta creates a captcha that is invisible to the user. Rather than force the user to prove they are a
human, we are allowing bots to prove they are bots. The captcha field is hidden and so humans will leave it blank. Bots
do not realize it is hidden so they will fill out the field. The validator checks to see if the field is blank, if it is
it allows the save, if not, it does not allow it.
To use less reverse captcha simply put 'validates_captcha' in the model and use the 'captcha_field' helper in your view.

http://m4n.github.com/validates_captcha/

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

内建验证

http://github.com/hardbap/trap_door

跟上面11楼提到反向Capchta一样的原理

Trap Door
就是个陷阱门，暗处藏有一个蜜罐字段，仅仅让垃圾机来填

前置过滤器检查是否有此field，如存在就把bots赶走

http://matthewhutchinson.net/2010/4/21/actsastextcaptcha

ActsAsTextcaptcha



http://rdoc.info/projects/hiddenloop/acts_as_textcaptcha

http://github.com/achiu/rack-recaptcha

Rack Middleware for CAPTCHA verification via Recaptcha API

这个问题值得研究：怎么样有效又方便用户

Humanizer is a very simple CAPTCHA method. It has a table with questions and answers which is used to validate that the user is an actual human. Currently only Mysql an Sqlite3 are supported. Tested only on Rails 3.
http://github.com/kiskolabs/humanizer