The encryption protocol commonly used to secure web traffic is HTTPS, which stands for Hypertext Transfer Protocol Secure. HTTPS employs TLS (Transport Layer Security) to encrypt the data exchanged between a user's browser and a web server. This encryption ensures that sensitive information, such as login credentials or personal data, is protected from interception by unauthorized parties. By utilizing HTTPS, websites enhance data integrity, authentication, and confidentiality, fostering user trust and improving overall security for online transactions.