TLS protects network traffic while it travels between computers. HTTPS is HTTP carried over a TLS connection, providing confidentiality, authentication, and detection of unexpected changes. Its older, less secure predecessor is SSL. section 3.3
During the initial TLS handshake, the client and server negotiate a cipher suite containing:
- A key-exchange algorithm, which securely exchanges keys for faster bulk encryption. section 3.3
- An authentication algorithm, which helps confirm that data is reaching the intended destination. section 3.3
- A bulk-encryption algorithm, which protects the exchanged traffic. section 3.3
- A message-authentication-code algorithm, which detects altered data packets. section 3.3
A digital certificate contains the public key used to establish a secure connection for a domain or IP address. Certificate authorities issue certificates, while browsers trust a configured list of authorities; unrecognized self-signed certificates trigger warnings. section 3.3
Application owners should treat TLS as an operational responsibility:
- Obtain a certificate, host it with the web application, and encourage every user agent to use HTTPS. section 3.4
- Revoke and replace certificates when they expire or their private keys may be compromised. section 3.4
- Use HSTS, require at least TLS 1.3 where applicable, restrict access to private keys, and monitor certificate transparency logs. section 7.13
Practical HTTPS protection
Acquire a certificate for the web domain and serve the application through HTTPS. Enable HSTS so communication consistently uses HTTPS, require a minimal TLS version to reduce downgrade attacks, and maintain a scripted process for revoking and reissuing certificates after suspected unauthorized access. section 7.13 section 3.4
