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CAPTCHA

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May 13, 2024 3 minute read

CAPTCHA, an acronym for Completely Automated Public Turing test to tell Computers and Humans Apart, is a type of challenge-response test used to determine whether or not a user is human. CAPTCHAs are often used on websites to prevent bots from submitting forms, creating accounts, or engaging in other automated activities. CAPTCHAs typically involve the user identifying distorted text, selecting images that match a certain pattern, or solving a simple math problem.

What is CAPTCHA?

CAPTCHAs are typically implemented using a combination of images, text, and audio. The user is presented with a challenge, which may involve identifying distorted text, selecting images that match a certain pattern, or solving a simple math problem. If the user successfully completes the challenge, they are allowed to access the website or service. CAPTCHAs are designed to be difficult for bots to solve, but easy for humans to complete.

How Does CAPTCHA Work?

CAPTCHA works by presenting a challenge to the user that is difficult for bots to solve, but easy for humans to complete. The challenge may involve identifying distorted text, selecting images that match a certain pattern, or solving a simple math problem. If the user successfully completes the challenge, they are allowed to access the website or service.

Why is CAPTCHA Important?

CAPTCHAs are important because they help to prevent bots from submitting forms, creating accounts, or engaging in other automated activities. This can help to protect websites and services from spam, fraud, and other malicious activity. CAPTCHAs also help to ensure that only real humans are able to access certain online resources.

How Can I Learn About CAPTCHA?

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Reading list

We've selected four books that we think will supplement your learning. Use these to develop background knowledge, enrich your coursework, and gain a deeper understanding of the topics covered in CAPTCHA.
Discusses the use of CAPTCHA as a tool for human computation, exploring its potential for solving complex problems.
Includes a chapter on CAPTCHA, providing insights into its security vulnerabilities and how to exploit them.
This comprehensive textbook on information security includes a chapter on CAPTCHA, providing an overview of its techniques and applications.
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