Deploying TLS 1.3 at scale with Fizz, a performant open source TLS library

This post details the development and large-scale deployment of Fizz, a C++ TLS library designed to implement TLS 1.3. It highlights Fizz's performance improvements over TLS 1.2, including reduced latency (especially with 0-RTT) and CPU utilization. Key technical features discussed are asynchronous I/O by default, scatter/gather I/O for zero-copy operations, and secure state machine design to prevent vulnerabilities. The post also covers the challenges of deploying TLS 1.3 at scale, including middlebox interference, and the workarounds implemented in Fizz. The open-sourcing of Fizz is announced as a contribution to the broader internet community.