Security on the Wire
The internet is a public network. Encryption is what keeps your passwords, messages, and bank details private as they cross it.
Your browser tells the server which encryption methods it supports.
The server sends its public key and a certificate signed by a trusted authority.
Both sides agree on a shared secret key used to encrypt the rest of the conversation.
What Is HTTPS?
HTTPS is HTTP wrapped in TLS (Transport Layer Security). The "S" stands for secure. It encrypts the data exchanged between your browser and a web server so that anyone intercepting the traffic sees only scrambled bytes.
Public and Private Keys
TLS uses asymmetric encryption. The server has a private key it never shares and a public key it gives to anyone. Data encrypted with the public key can only be decrypted with the private key. This lets your browser send a secret session key to the server safely.
Certificates and Trust
A TLS certificate binds a public key to a domain name. Certificate Authorities (CAs) validate ownership and sign certificates. Your browser trusts a built-in list of CAs and warns you if a certificate is invalid or expired.
Why It Matters
- Confidentiality: No one can read your data in transit.
- Integrity: No one can tamper with your data without detection.
- Authenticity: You can verify you're talking to the real website, not an impostor.
Key Term
TLS (Transport Layer Security)
The cryptographic protocol that secures HTTPS. It replaced the older SSL standard and is regularly updated with stronger algorithms.