How is HTTPS security achieved?

HTTPS security is achieved through a combination of three key mechanisms based on the TLS/SSL protocol:

Encryption: Data exchanged between the client and server is transformed into an unreadable format using encryption algorithms. This prevents interception and reading by third parties. Different types of encryption are used:
- Symmetric encryption (e.g., AES) for encrypting the traffic itself after the connection is established.
- Asymmetric encryption (e.g., RSA, Elliptic Curve Cryptography) for exchanging the symmetric key and verifying the server's authenticity.
Data integrity: Cryptographic hash functions (e.g., SHA-256) are used to create a unique "fingerprint" of the transmitted data. The recipient can compute the hash independently and compare it with the received hash. Any change in the data will alter the hash, signaling a breach of integrity.
Authentication: Digital certificates issued by trusted Certificate Authorities (CAs) are used for server authentication. The certificate contains the server's public key and is signed with the CA's private key. The browser trusts certain CAs, and if the certificate's signature is valid, the client can be confident it is communicating with the genuine server, not an attacker.

Thus, HTTPS ensures confidentiality, integrity, and authenticity of data during transmission.