Mifare Desfire EV1

Hello, I have a question,

I have a card for accessing to the gym, this card is DESfire EV1. I would like to know what is the best chip for this card and purpose

The DESFire EV1 is a great chip with many security features that have yet to be cracked or broken. The problem is you cannot easily migrate or clone a DESFire application to another tag, so your best option would be to get a flexDF and ask if you can enroll that tag with your gym’s system to enable you to use it instead of or along with your card.

Be aware though, most systems consider the fob or key card to be exclusively used for that application, and even though the DESFire EV1 can have multiple applications defined on it, typically a system developer will greedily just take up the entire available space on a DESFire chip, even if they don’t need it.

For example, the flexDF is 8k… and a simple gym access application should only need 1k or less… leaving 7k open for other applications. However, I can almost guarantee you that if you enrolled your flexDF at the gym, that system would create a huge application and take up all the space, for absolutely no reason… leaving your flexDF basically useless for anything but gym access.

There is also the issue of key management… those systems also set keys and change the master key, and you don’t get access to those keys… so again your flexDF will be useless for any other type of application… which is really lame.

I think the coming answer is VivoKey… we are exploring ways to emulate Mifare and DESFire applications on VivoKey that are still under your control and manageable by you, meaning you can remove it later if you don’t want it or would like to reclaim that space.

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