How does the HTTPS protocol work? Describe the process of establishing a secure connection, encryption, and key management.

HTTPS is an extension of HTTP using the TLS/SSL protocol to provide a secure connection.

The process of establishing a secure connection (TLS handshake) includes the following steps:

1. The client sends a request to the server to establish a secure connection, indicating supported TLS versions and cipher suites.
2. The server responds with its certificate, containing the public key and confirming its identity through a certification authority (CA).
3. The client verifies the certificate (CA signature, validity period, domain match).
4. The client generates a random value (pre-master secret), encrypts it with the server's public key, and sends it.
5. The server decrypts the pre-master secret with its private key.
6. Both compute a shared secret (master secret) based on the pre-master secret and other parameters.
7. Symmetric keys for encryption and data authentication are generated based on the master secret.
8. The client and server exchange confirmation messages indicating that subsequent traffic will be encrypted.

After this, all HTTP traffic is transmitted over a secure channel using symmetric encryption (e.g., AES), ensuring data confidentiality and integrity.

Key management is based on asymmetric cryptography for secret exchange and symmetric cryptography for session encryption, which optimizes performance.