If you take public transport in many of the world’s cities, your ticket will be an NFC card which you scan to gain access to the train or bus. These cards are disposable, so whatever technology they use must be astonishingly cheap. It’s one of these which [Ken Shirriff] has turned his microscope upon, a Montreal Métro ticket, and his examination of the MiFare Ultra Light it contains is well worth a read.
This is a companion discussion topic for the original entry at https://hackaday.com/2024/06/26/as-cheap-as-chips-the-mifare-ultra-light-gets-a-closer-look/