What Is A CAPTCHA, And How Does It Work?

 
CAPTCHA or Captcha (pronounced ch-Cap-uh), meaning "completely automated public Turing test to tell computers and people outside" is a form of provocation test / answer to ensure that the response is generated only by those and not a computer. In simple terms, the CAPTCHA word verification you will encounter at the end of a registration form when you signed up for Gmail or Yahoo. The following image shows typical examples of CAPTCHA. Almost all Internet users will experience in their daily use CAPTCHA, but few are aware of what it is and why they are used. So in this post, you will find detailed information on how the CAPTCHA works and why they are used. What is the exact purpose CAPTCHA Served? CAPTCPA is mainly used to prevent software robots (bots) to take action on behalf of the real man. For example, when you open a new mail account, you will find a CAPTCHA to the end of the registration form to ensure that the form is filled out by a legitimate interest of men and not automated software or computer bot. The main purpose of CAPTCHA is to propose a test that is simple and easy for any human being to answer, but for a team, it is almost impossible to solve. How to create a test that can tell Computers and Humans Apart? For many CAPTCHA may seem silly and boring, but in reality it has the ability to protect systems against malicious attacks, where people try to game the system. Attackers can use automated software to generate a huge amount of applications, which causes a high load on the target server, which could degrade the service quality of a given system, whether due to expenses or abuse of resources. This could affect millions of users and their legitimate demands. CAPTCHAs can be deployed to protect systems vulnerable to spam e-mail, such as services from Gmail, Yahoo and Hotmail. Users that CAPTCHA? CAPTCHAs are primarily used by sites that offer services such as online surveys and registration forms. For example, offers Web-based email services like Gmail, Yahoo and Hotmail free e-mail accounts for their users. But each registration process, CAPTCHAs are used to prevent spammers from using a bot to generate hundreds of spam e-mail accounts. Designing a system CAPTCHA CAPTCHA has been designed so that the computer does not have the ability that people have when it comes to processing visual information. It 's easier to allow people to view photos and collect models such as the computer. This is because computers are missing a real intelligence, that people have by default. CAPTCHA implementation by users of the image, which has been distorted or occasionally stretch marks, only that people should be able to identify. Sometimes the characters are deleted or presented in a noisy environment is more difficult for computers to find patterns. Most but not all, CAPTCHAs rely on visual evidence. Some web sites implement a CAPTCHA system completely different to tell humans and computers together. For example, a user is presented with four images containing three photographs of animals and containing a flower. The user has to select only those images that contain the animals in them. The Turing test can be easily solved by any human being, but almost impossible for a computer. Breaking the CAPTCHA The challenge is to break the CAPTCHA really hard to teach the computer how to process information the same way as people think. Algorithms and Artificial Intelligence (AI) was designed for the computer to think like people, when it comes to images of textures. However, no general algorithm that can go through and break the CAPTCHA system, and then each algorithm CAPTCHA must be dealt with separately. It might not work 100 percent of the time, but it can work all the time that spammers the trouble.

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