SSL/TLS Explained
Last Updated: January 10, 2026
Every time you see that padlock icon in your browser, there is a sophisticated cryptographic protocol working behind the scenes. That protocol is TLS (Transport Layer Security), and it is the foundation of secure communication on the internet.
Without TLS, every password you type, every credit card number you enter, and every private message you send would travel across the internet in plain text.
Anyone sitting between you and the server, whether that is your ISP, a coffee shop's WiFi network, or a malicious actor, could read everything.
In this chapter, we will cover:
- Why do we need TLS?
- How the TLS handshake works
- Certificates and Certificate Authorities
- Symmetric vs asymmetric encryption
- TLS versions and their evolution
- Mutual TLS (mTLS) for service-to-service communication
- Best practices for TLS configuration