TLS
Transport Layer Security protects application data in transit and authenticates one or both peers.
Jul 11, 2026
Transport Layer Security (TLS) is a protocol that protects application traffic between two endpoints. HTTPS is HTTP carried over TLS.
TLS provides three main properties:
- Confidentiality: encryption prevents a passive observer from reading application data.
- Integrity: authenticated encryption detects modification of protected records.
- Authentication: certificates or pre-shared keys bind cryptographic proof to a peer identity. HTTPS normally authenticates the server; mTLS also authenticates the client.
TLS does not prove that an application is trustworthy, prevent compromise at either endpoint, or protect data after it has been decrypted.
Handshake And Records
The TLS Handshake negotiates a protocol version and algorithms, authenticates peers, and derives traffic keys. The record protocol then fragments and protects application data using those keys.
Applications should use maintained TLS libraries rather than implement either layer themselves. Library and platform defaults evolve as attacks and interoperability requirements change.
Trust
Certificate authentication depends on both path validation and service-identity checks. A valid signature chain alone is not enough: the requested hostname must match an identity in the certificate. Certificate Chain of Trust covers this process.
TLS Deployment covers certificate automation, HSTS, protocol policy, and testing.
Versions
TLS 1.0 and TLS 1.1 are deprecated. Current deployments normally support TLS 1.2 and TLS 1.3 while preferring TLS 1.3. Compatibility requirements and platform policy determine when TLS 1.2 can be removed.