The Illustrated DTLS Connection

Published at https://dtls.xargs.org

• site/: page source for the finished product
• server/server.c: server code
• client/client.c: client code
• wolfssl/: patch and build of wolfSSL that removes any random aspects of the documented connection
• captures/: PCAP and keylog files

See also https://github.com/syncsynchalt/illustrated-tls13 for a TLS 1.3 version of this project.

Build instructions

If you'd like a working example that reproduces the exact handshake documented on the site:

git clone https://github.com/syncsynchalt/illustrated-dtls.git
cd illustrated-dtls/
cd wolfssl/
make
cd ../server/
make
cd ../client/
make

Then open two terminals and run ./server in the server/ subdir and ./client in the client/ subdir.

This has been shown to work on MacOS 12 and various Linuxes and only has a few easy-to-find dependencies: gcc or clang, make, patch, etc.