What is HTTPS?

HTTPS (Hypertext Transfer Protocol Secure) is an extension of the HTTP protocol that ensures secure communication between the client (browser) and the server. It uses data encryption, typically based on TLS (Transport Layer Security) or SSL (Secure Sockets Layer) protocols, to protect against interception, tampering, and eavesdropping of transmitted information.

Main principles of HTTPS operation:

Handshake: At the beginning of a session between the client and the server, a handshake occurs during which the parties exchange information to establish a secure connection.
Key exchange: During the handshake, a session key is generated and exchanged, which will be used for encrypting and decrypting data throughout the session.
Server certificate: The server provides the client with its digital certificate issued by a trusted certification authority (CA). This certificate confirms the server's authenticity.
Certificate verification: The client verifies the server's certificate authenticity by checking its signature from the certification authority.
Encryption: After establishing a secure connection, all transmitted data is encrypted using the session key.

Main advantages of HTTPS:

Confidentiality: Data is protected from interception by third parties.
Integrity: It guarantees that data has not been altered during transmission.
Authentication: The server's authenticity is verified, protecting against phishing and man-in-the-middle attacks.

Using HTTPS is standard for websites, especially those handling confidential information (e.g., personal data, payments). Browsers typically display a lock icon in the address bar for sites using HTTPS.

Example URLs in HTTP and HTTPS:

HTTP: http://example.com
HTTPS: https://example.com