File structure and file type resolution in the PBOC

1. Clear two specifications, a. ISO7816 B.EMV Specification/PBOC specifications, the difference between the two, 7816 is ISO formulated, is an international norm, and the EMV specification is the card organization, is to follow the ISO7816 norms, the PBoC is copied EMV norms, must also follow the ISO7816 specification.

2. Several common file types:

A. Mf,df,ef, this is the file defined in ISO7816, MF is also a DF, the topmost DF, called the root directory, and EF is the normal file in the directory

B.ADF,DDF,AEF, this is the EMV/PBOC definition of the file, PBOC/EMV definition of the IC card file structure is in line with the ISO7816 standard. ADF and DDF are actually two mappings of DF, and AEF is a mapping of EF. When the program accesses, it accesses ADF,DDF and AEF, not DF and EF.

C. This mechanism is very much like the address of the operating system, our program can not access the physical address of the system, but only the virtual address mapped by this physical address (memory), and the same physical address can be mapped to a different virtual address. So we can think of DF, EF as a physical file structure, and ADF,AEF as a virtual file structure that can be accessed by the program.

What is the difference between 3.ADF and DDF?

A. The ADF is already able to identify one or a group of applications (why there is a set of applications, because there is a partial aid match, refer to the PBOC/EMV document), because it is the application's entry file.

B. DDF is a directory entry, it has an ADF under it, or it may be a DDF, of course, there may be nothing, in short it is a directory.

C. ADF uses the ADF name to identify the application, and the ADF name is the aid. An aid represents an application, such as an e-wallet app, debit app, credit app, and so on.

File structure and file type resolution in the PBOC