Explore the development of a new TLSv1.3 stack from scratch in this 45-minute conference talk from linux.conf.au 2021. Dive into the design decisions, challenges, and approaches taken by the LibreSSL project team as they implemented a compact TLS stack in just under 7,000 lines of C code. Learn about fitting new code into existing APIs, addressing interoperability issues, and testing complex protocols. Examine the pitfalls and implementation complexities arising from the RFC, and gain insights into the differences between TLSv1.3 and TLSv1.2. Cover topics such as handshake state machines, key derivation, record layer security, and legacy stack compatibility. Conclude with a summary and Q&A session to deepen your understanding of TLS implementation.