Which protocol is used for secure data transfer over the Internet?

The protocol used for secure data transfer over the Internet is HTTPS. HTTPS, which stands for Hypertext Transfer Protocol Secure, is an extension of HTTP (Hypertext Transfer Protocol) that incorporates SSL/TLS (Secure Sockets Layer/Transport Layer Security) to provide a secure channel over a computer network. This security aspect ensures that data transferred between a user's web browser and a web server is encrypted, making it much more difficult for unauthorized parties to intercept or tamper with that data.

The use of HTTPS is crucial for any websites that handle sensitive information, such as online banking, e-commerce sites, or any platforms requiring user login credentials. It assures users that their data is safeguarded during transmission.

In contrast, the other protocols listed have different primary functions and security features. FTP (File Transfer Protocol) is used for transferring files but does not inherently provide encryption for those files, making it less secure. HTTP, while used for transmitting data over the web, lacks the encryption layer that HTTPS provides. SMTP (Simple Mail Transfer Protocol) is used for sending emails and may have security implementations, but it is not primarily designed for secure data transfer on the web like HTTPS.