Which protocol is used to encrypt HTTP traffic?

The protocol used to encrypt HTTP traffic is SSL, which stands for Secure Sockets Layer. SSL works by establishing a secure and encrypted link between a web server and a client (usually a web browser). This encryption ensures that any data transferred over this connection, such as personal information, passwords, and payment information, remains confidential and is protected from potential eavesdropping or tampering by malicious actors.

SSL has largely been succeeded by Transport Layer Security (TLS), which is the next generation of this protocol and provides even stronger security features. However, the term SSL is still commonly used to refer to both SSL and TLS. When a web address uses HTTPS (Hypertext Transfer Protocol Secure), it indicates that SSL/TLS is being used to encrypt the communication.

The other options do not pertain to the encryption of HTTP traffic. FTP is used for transferring files, SMTP is used for sending emails, and IMAP is used for retrieving emails. These protocols serve different purposes and do not include built-in mechanisms for encrypting web traffic in the same way that SSL/TLS does for HTTP.