The type of encryption used in HTTPS is known as Transport Layer Security (TLS). TLS secures the data transmitted between a user's browser and a web server by encrypting the connection, ensuring that sensitive information like passwords and credit card numbers remains private. It includes mechanisms for authentication, ensuring that information is sent to the correct server, and integrity checks to prevent data from being altered during transmission. HTTPS is crucial for maintaining user trust and securing online transactions in today’s digital landscape.