HTTPS works by using SSL/TLS encryption to secure the transfer of data between the client (for example, a web browser) and the server. The following steps are performed in the background during an HTTPS connection, of which the user himself is not aware: Handshake: Before the actual transmission can take place, the client and server must agree on a common encryption method. This takes place during the so-called handshake. Certificate check: The client then checks whether the server's certificate was issued by a trusted certificate authority. In this way, it can be ensured that one is actually communicating with the expected server. Key exchange: Symmetric keys are then exchanged between the client and server, which are used to encrypt the data. Data transmission:  The actual transmission of the data is now encrypted. The client encrypts the data with the received key and sends it to the server. The server can decrypt the data only with its own, previously exchanged key. Verification: To ensure that the data is not tampered with, both client and server calculate a checksum of the transmitted data and compare it.