Which protocol is commonly used for securely transmitting data over the Internet?

HTTPS, or Hypertext Transfer Protocol Secure, is commonly used for securely transmitting data over the Internet. It is essential because it combines HTTP with an extra layer of security provided by the Transport Layer Security (TLS) or Secure Sockets Layer (SSL) protocols. This means that data transferred between a web server and a browser is encrypted, safeguarding it from interception and eavesdropping.

Using HTTPS ensures that sensitive information, such as credentials, payment information, and personal data, is transmitted securely, making it vital for websites that handle confidential information. It also provides authentication, which verifies that the website being accessed is the legitimate site and not an imposter, further enhancing security.

In contrast, the other protocols listed are not designed for secure data transmission. FTP is primarily used for transferring files but does not provide encryption, which can expose transmitted data. HTTP, while essential for web browsing, lacks security features and transmits data in plain text, making it vulnerable to attacks. SMTP is used for sending emails but, without additional security measures, it also transmits data without encryption. Therefore, HTTPS is the preferred choice when secure data transmission is needed on the Internet.