[Muscle] Returning custom data in a Mifare/14443 ATS??

[Kim O'Sullivan]

Title: Message

Hi Folks,

 

I am currently doing a bit of research into a multi-application protocol for Mifare/14443A compatible cards.
The protocol requires that an application is able to read directory information from the card to see what applications are available, and where (eg. which sector).

 

One person mentioned the possibility of using the Answer to Select (ATS) to deliver this information (to speed up transaction times).
I have never heard of this being done before and wanted to know if anyone else has come across a scenario where custom information is being sent over the ATS.

 

So my questions are:

 

1. Can you somehow issue a Request for ATS that returns custom information that can then be read?
(If so, a) how do is this done, b) where does the data come from in the first place and c) is this something you would have to design a custom reader to access or can it be done by an end application?)

 

2. If it is not possible, is there another possible approach we could take to allowing someone to enumerate the applications on a card without having to go through a select, authenticate and then read? (and thus wasting valuable ms :)

 

3. If not, I would be interested in hearing peoples opinions of how application enumeration could be implemented or some pointers to existing methodologies for doing this. (I have taken a look at Phillips MADv2 but that is the only one I have found so far)

 

Any help would be appreciated!

 

Thanks :)
Kim

 

P.S. Just to clarify by application I simply mean an amount of memory space reserved somewhere on the card for a system to use eg. Access control, electronic purse, cardholder information, etc etc.