In this paper we describe a case study of the re-engineering process used to discover the
low-level application protocol data units (APDUs) and their associated significance when used in
communications with the Portuguese e-id smart card. This was primarily done simply to learn the
processes involved given the low level of documentation available from the Portuguese government
concerning the inner workings of the Citizens Card. However it was also done in order to produce a
generic platform for accessing and auditing the Portuguese Citizen Card and for using Match-on-Card
biometrics for use in different scenarios. Given that no documentation is available concerning the use
of the Match on Card capabilities of the e-id card this is a challenging procedure