What is a CAPTCHA used for on websites?

A) Verifying that users are human and not bots

B) Displaying advertisements

C) Playing videos

D) Blocking access to websites

Show Answer

A) Verifying that users are human and not bots

A CAPTCHA, which stands for “Completely Automated Public Turing test to tell Computers and Humans Apart,” is a security measure used on websites to determine whether the user is a human or a computer program (bot). CAPTCHAs are typically presented as puzzles or challenges that require human-like problem-solving skills to complete. The primary purposes of CAPTCHAs on websites are as follows:

1. Bot Prevention: CAPTCHAs are primarily used to prevent automated bots or scripts from engaging in activities that could be harmful or disruptive. Bots can be used for various malicious purposes, such as spamming comment sections, creating fake accounts, or conducting credential stuffing attacks to guess login credentials.
2. User Verification: CAPTCHAs help ensure that the user interacting with a website or web application is indeed a human. This verification is essential in scenarios where the website wants to establish user identity or validate a user’s intent, such as when creating an account or making a transaction.
3. Protection Against Web Scraping: Web scraping bots can automatically extract data from websites. CAPTCHAs can deter web scraping by making it more difficult for automated programs to access and extract information from web pages.
4. Mitigation of Fraudulent Activities: In e-commerce and online services, CAPTCHAs are often used to prevent automated bots from engaging in activities like buying limited-stock items, manipulating voting systems, or attempting fraudulent transactions.
5. Comment and Form Spam Prevention: Websites that allow users to leave comments or submit forms are often targeted by spammers using bots. CAPTCHAs can help reduce spam by ensuring that a human is submitting the content.
6. Enhancing Security: CAPTCHAs contribute to the overall security of a website by reducing the risk of automated attacks, unauthorized access, and data breaches.

CAPTCHAs come in various forms, but they typically involve the user solving a challenge or puzzle that is easy for a human to understand but challenging for automated scripts to solve. Some common types of CAPTCHAs include:

• Image-based CAPTCHAs: These present the user with distorted characters or objects within an image that must be identified or selected.
• Text-based CAPTCHAs: Users are often asked to type a series of distorted or obscured characters into a text field. This is sometimes referred to as a “reCAPTCHA.”
• Checkbox CAPTCHAs: Users are asked to check a box to confirm that they are not a robot. In some cases, this checkbox is followed by additional challenges if the system suspects potential bot activity.
• Audio CAPTCHAs: These present users with an audio challenge that involves identifying spoken words or numbers.
• Interactive CAPTCHAs: These may require users to perform certain actions, such as dragging and dropping objects or solving puzzles.

While CAPTCHAs are effective at reducing automated bot activity, they can also be a source of frustration for users, especially if the challenges are too difficult or if the CAPTCHA implementation is not user-friendly. As a result, web developers strive to strike a balance between security and user experience when implementing CAPTCHAs on websites.