Page 1 of 1

files in eJava Token

Posted: Fri Nov 27, 2015 2:55 am
by Crawford
I have installed two applets into eJava Token. I use pyApdutool to list the APPLET-AID, as follow,

Here are my questions:
- Where are the two applets in the eJava Token? in MF or DF?
- Is there any way to see the AID of MF and all the other EFs and DFs of eJava Token?
- How I can create a DF?

Any help would be appreciated!

Re: files in eJava Token

Posted: Mon Nov 30, 2015 2:31 am
by mabel
To the best of my knowledge, the files in eJava Token should be the same as java card. If I am right, the answers to your questions should be:

A1: Consider each Java Card application to be a DF directly below the MF. Though, be aware that Java Cards only make use of parts of the ISO 7816-4 file system concept and that the MF itself is not necessarily selectable by default.

A2: From an API perspective, only DF names can be AIDs. Consider AIDs to be DF names that comply to a specific format. MF and EF have file IDs. However, as there is no file system concept on Java Cards, there are no addressable MF, EFs by default. So the only listable components that are on a Java Card are applets and applet packages.

A3: You can create a DF by installing (and making selectable) an applet.

Re: files in eJava Token

Posted: Mon Nov 30, 2015 11:28 pm
You can understand that the JCVM manage the applications itself, has no DF and EF concept.
If your applet has data manage as file system, you can emulate the file system.
The eJava Token card manager gives you the functions to list/create/delete applications with each command: GET STATUS/INSTALL for [LOAD/INSTALL/SELECTABLE]/DELETE.

And you can understand that one applet as one DF, If your applet has datas, you can store these datas in EFs.