There’s a guy that reverse engineered them but he would only describe the broad strokes. Part of the system works with the value stored on the card so there is

There’s a guy that reverse engineered them but he would only describe the broad strokes. Part of the system works with the value stored on the card so there is a way to get free rides but it’s not easy to figure out. https://events.ccc.de/congress/2005/fahrplan/attachments/594-paper_MagneticStripeTechnology2.pdf https://events.ccc.de/congress/2005/fahrplan/attachments/594... https://events.ccc.de/congress/2005/fahrplan/events/765.en.html https://events.ccc.de/congress/2005/fahrplan/events/765.en.h... https://blog.yossarian.net/2016/07/17/Decoding-the-Metrocard-Part-2 https://blog.yossarian.net/2016/07/17/Decoding-the-Metrocard...