Content Security Policy (CSP) is a crucial security standard that helps prevent various types of attacks on websites, such as Cross-Site Scripting (XSS) and data injection attacks. It works by allowing website administrators to specify which sources of content are trusted and permitted to be loaded or executed by a user's browser.

Instead of relying solely on the browser to detect malicious content, CSP provides a whitelist approach. You define directives in an HTTP header that tell the browser exactly where it can load resources from. These resources include:

• Scripts (JavaScript files)
• Stylesheets (CSS files)
• Images, fonts, and media
• Frames and objects
• Connections (like AJAX requests)

For example, a CSP directive can state, "Only execute JavaScript that comes from my own domain or from a specific trusted CDN." If an attacker tries to inject a malicious script from an untrusted source, the browser will block it.

Implementing CSP is a best practice for modern web hosting and development. It adds a powerful layer of defense, protecting both your site's data and your visitors. While it requires careful configuration to avoid breaking legitimate site functionality, the enhanced security it provides is invaluable for any serious website.