In this project, I started to reverse engineer payment card terminals because they seemed to be an interesting target for security research, given the high stakes involved. Although I initially didn’t knew much about this industry, I did expect a ton of security features and a very security-hardened device. And to some degree, this was also correct. First Look The model I went with is a Worldline Yomani XR terminal. Although it seems to be discontinued at the time of writing, this is the model t...