What technology is commonly used to make online transactions secure?

SSL (Secure Sockets Layer) certificates are essential for securing online transactions, particularly on websites that handle sensitive information like payment details or personal data. When a website uses an SSL certificate, it establishes a secure, encrypted connection between the web server and the user's browser. This encryption prevents third parties from intercepting and viewing the data being transmitted, ensuring that information remains private and secure.

SSL certificates also instill trust in users; when they see the padlock icon in the browser's address bar or notice that the URL begins with "https," it signals that their connection is secure and that the site is protecting their data. This level of security is vital for e-commerce sites, online banking, and any service requiring sensitive information.

In contrast, the other technologies mentioned—HTML5, JavaScript, and CSS—serve different purposes. HTML5 is a markup language used for structuring content on the web. JavaScript is a programming language that enables dynamic content and interactivity, while CSS is used for styling the presentation of web pages. Although these technologies enhance user experience and design, they do not provide the security necessary for safely conducting online transactions.