If you are into Node.js, ZeroMQ, security or distributed application you can read the two articles in the community section of RisingStack.
ZeroMQ & Node.js Tutorial - Cracking JWT Tokens (Part 1.), is focused mostly on theory and describes what a JWT token is and what will be our approach to try to crack one of them.
ZeroMQ & Node.js Tutorial - Cracking JWT Tokens (Part 2.), instead, focuses on coding and it's a step by step guide on how to build the working application.