Using CAPTCHA for Your Website

Billie Hillier

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CAPTCHA, which stands for “Completely Automated Public Turing test to tell Computers and Humans Apart,” is a type of security measure used online to distinguish between human users and bots or automated programs.


How Does CAPTCHA Work?

Well, CAPTCHA essentially presents a test that’s easy for a human to pass, but hard for a computer. Here’s a rundown of how it generally operates:

Presentation of the Test: When you visit a website, you might encounter a CAPTCHA test. This could be when you’re creating an account, posting a comment, or making a purchase.

Types of Tests: CAPTCHAs come in different forms. Some CAPTCHAs ask you to type in a series of distorted letters and numbers displayed in an image. Others might ask you to select all images from a series that contain a specific object, like a traffic light or a bus.

Test Completion: As a human user, you would complete the test by entering the text or selecting the images correctly.

Evaluation: The CAPTCHA software then evaluates your response. If you pass the test, you’re deemed a human and permitted to proceed.

The main purpose of CAPTCHA is to protect websites from spam and abuse by bots. Since bots are programmed to perform specific tasks automatically and rapidly (like creating numerous fake accounts or posting spam messages), a CAPTCHA test can effectively prevent these actions by posing a task that’s difficult for bots to solve.

Read our article on How to Block Spam Bots.

However, while CAPTCHAs provide a level of security for websites, they aren’t infallible. Advanced bots and artificial intelligence can sometimes crack CAPTCHAs, and they can also pose accessibility issues for individuals with certain disabilities.

It’s important for websites to balance security with user-friendliness, and to consider alternative security measures like two-factor authentication or behavior analysis.

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