SSL and TLS

Overview

TLS secures data in transit by encrypting communication and validating endpoint identity using certificates.

TLS Essentials

• Certificates signed by trusted authorities
• Strong cipher suites and protocol versions
• Certificate rotation and expiry monitoring

sequenceDiagram
    participant Client
    participant Server
    Client->>Server: ClientHello
    Server-->>Client: Certificate + ServerHello
    Client->>Server: Key exchange
    Server-->>Client: Encrypted session established

Practical Example

ssl_protocols TLSv1.2 TLSv1.3;
ssl_ciphers HIGH:!aNULL:!MD5;

Production Example

Public APIs typically terminate TLS at load balancers and may use mTLS internally for service-to-service trust.

Common Pitfalls

• Expired certificates causing avoidable outages
• Legacy protocol support left enabled
• No automated renewal process

Key Takeaways

• TLS is mandatory for modern application traffic.
• Certificate lifecycle automation improves reliability.
• Strong protocol and cipher policies reduce attack surface.