What are security headers in HTTP responses used for?

Security headers in HTTP responses play a crucial role in guiding web browsers on how to handle content securely, making option B the correct choice. These headers are primarily designed to enhance the security of web applications by specifying policies related to various security aspects.

For example, headers such as Content Security Policy (CSP) instruct the browser on which resources are permitted to load, thus mitigating risks like cross-site scripting (XSS) attacks. Similarly, headers like X-Content-Type-Options prevent browsers from interpreting files as a different type than what is intended, which helps in safeguarding against certain types of attacks.

This functionality is essential for enforcing security measures directly through the browser, which helps in protecting both the server and the end-user from various vulnerabilities. Hence, security headers effectively inform the browser regarding actions to take with the site content, allowing for a more secure user experience.

In contrast, while encrypting data transferred is a critical aspect of security, it is typically managed by Transport Layer Security (TLS) rather than through headers. Authentication of users is handled through other mechanisms such as tokens or cookies, rather than security headers. Furthermore, performance optimization relates to the efficiency of resource loading and is typically addressed through caching strategies or content delivery networks, not specifically