Those who use website services and social network must have known about CAPTCHA. Anyone that loves making website or has their own dynamic website must have suffered from spam problem. Therefore, what you need to protect your website is CAPTCHA. This article recommends you an effective anti-spam tool, it is reCAPTCHA.
According to Wikipedia, “reCAPTCHA is a system originally developed at Carnegie Mellon University that uses CAPTCHA to help digitize the text of books while protecting websites from bots attempting to access restricted areas”
CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a tool which is able to distinguish people with automatic tools of computers. It prevents them from performing actions automatically to the system such as sending datat, login.. reCAPTCHA is also a system making CAPTCHA. The interesting thing here is that you don’t need to program algorithm performed by the main server.You can use this free effective anti-spam tool for your website.
Here are several reasons why almost peole choose reCAPTCHA instead of CAPTCHA:
- Availble and free
- Easy to integrate and use, not need to program, improve code against spam.
- Add CAPTCHA sound for the blind
The feature making reCAPTCHA original and different from others is that you help it to digitize a huge amount of books in its server while you use it free. So,there are two advantages for both sides, which is the reason why reCAPTCHA free service exists as an effective tool against spam today. How did they do?
As you know, if you want to digitize the text of old magazines or newspapers to edit, you have to scan them first, then usethe recognition software to turn them into the characters on the computer. It is difficult to recognize different fonts after scanning. For example, here are the differences between words and the result of the recognition software:
Due to limitations of the programming that OCR (Optical ch @ racter Recognition) can not recognize accurately the text,whereas human ability of word recognition is much better (especially handwriting.) The writers of ReCAPTCHA were very clever at using public power to convert " vain efforts" into “ useful efforts" for itself.
How reCaPTCHA works is extremely simple.reCAPTCHA takes words which OCR is not sufficient in its database and combines them with one word it already knows.To display the screen and require users to type two words.Then it checks the words it knows,if the word is the same to the typed word, it will conclude that the other are also right and interpose them into its digital database.
Realizing the benefits of reCAPTCHA,September 2009,Google bought the technology to replace its old system, CAPTCHA (the hacker being overtaken). At the same time, what Google wants is this tool, which will help them accelerate the large number of documents in its electronic book store.
To use reCAPTCHA for your website,you need to register an account here: https://admin.recaptcha.net/recaptcha/crea-tesite/
The system will take you to the login page of Google,please login with your Gmail account,login is complete you just declare your website address to get a registration code.Each site has a registration code and can be used only after registration.
To use for your site,you use this programming model : http://recaptcha.net/resources.html