HTTPS, or Hypertext Transfer Protocol Secure, ensures secure communication between a web browser and a server. It works by encrypting the data transmitted between them, preventing eavesdropping and tampering.
The HTTPS Process: A Simplified Explanation
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Authentication: The browser first verifies the website's identity by checking its SSL/TLS certificate. This certificate, issued by a trusted Certificate Authority (CA), confirms the website's ownership and authenticity.
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Key Exchange: A secure key exchange takes place using public-key cryptography. The server sends its public key to the browser. The browser then generates a symmetric key (a secret key used for faster encryption) and encrypts it using the server's public key. Only the server, possessing the corresponding private key, can decrypt this symmetric key.
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Encrypted Communication: Once the symmetric key is established, all further communication between the browser and server is encrypted using this key. This provides confidentiality and integrity, protecting sensitive data like passwords and credit card information.
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Data Transmission: The encrypted data is exchanged between the browser and the server. Because the data is encrypted, even if intercepted, it is unreadable without the symmetric key.
The Role of TLS/SSL
HTTPS uses the Transport Layer Security (TLS) protocol (formerly Secure Sockets Layer, or SSL). TLS handles the encryption and authentication processes described above. It uses an asymmetric public key infrastructure to securely exchange the symmetric key crucial for fast encryption of the actual data transfer.
What HTTPS Protects
- Confidentiality: Prevents eavesdropping on the communication.
- Integrity: Ensures that the data hasn't been tampered with during transmission.
- Authentication: Verifies the identity of the website, preventing man-in-the-middle attacks.
While an adversary might see that a connection to a specific website is happening, the actual content of the communication is protected by encryption.
