What does it mean for a smart card to be PKCS#15 compatible?

Question

Many smart card vendor advertise their smart card as PKCS#15 compatible or ISO 7816-15 compatible (more or less these two documents are the same). After reading both documents I understood that PKCS#15 represents specific layout of filesystem smart card and specific content encoding of files representing PKCS#15 sturctures(ODF, PuKDF, PrKDF, CDF, AODF, SKDF etc).

In my opinion any ISO 7816 filesystem compatible smart card is compatible with this standard.

So my question is: What does it mean when smart card is advertised as PKCS#15 compatible? What are your thoughts about this? Are there any cards where these PKCS#15 files are implemented internally in the card os( not involving external program to the card mapping these structures to dedicated files, transparent or record files)?

Answer 1

I would also consider PKCS#15 compatibility mostly as a matter of the file system. Note, that all these information provided on the card has no active functionality on its own. You still need an active part, i. e. software, which reads it, and translates the information found into the appropriate commands to send to the card. This is for instance done in an PKCS#11-compatible API running on the PC.

Answer 2

PKCS#15 and the more recent ISO/IEC 7816-15 standards describes a method of finding the files, objects and features of file based cards. ISO/IEC 7816-4 describes a framework for implementing and using file based cards, but it does not describe how to discover which files, objects and features are contained on the personalized card.

Neither of these two standards are complete enough to fully describe a file based smart card, but it does enable persons to define protocols on the cards and write software that may be reused. If a card is advertised as PKCS#15 compatible then it you should be able to use it (to a certain degree) by implementing PKCS#15 for that card or by using an customized existing solution.