What is the purpose of using the X-Frame-Options header in a web application?

The use of the X-Frame-Options header in a web application is primarily aimed at preventing clickjacking attacks. Clickjacking is a malicious technique where an attacker tricks a user into clicking on something different from what the user perceives, possibly leading to unintended actions. By implementing this header, web developers can control whether their content can be embedded in a frame or iframe by other websites.

When set, the X-Frame-Options header can instruct the browser to disallow any framing of the content, thus protecting users from being manipulated into clicking on hidden elements or content. There are different directives the header can use, such as "DENY," which completely prevents the site from being displayed in an iframe, or "SAMEORIGIN," which permits the content to be displayed in an iframe only if the request comes from the same origin.

Other options mentioned do not directly relate to the primary functionality of the X-Frame-Options header. Cross-origin resource sharing pertains to how resources are shared across different domains, while enhancing loading speed and encrypting data in transit relate to site performance and security protocols, respectively.