Ah Ok, #hvv #prepaid Card nutzt #Mifare #DESFIRE Light #MF2DL100

Do you guys know any #android tooling which supports #DESfire EV2 'secure messaging', i.e. trying to authenticate with a custom AES key?

#programming #embedded

Trying to implement #desfire EV2 secure messaging.
I must have done something wrong, it doesn't work out somehow.

Symmetric authentication is a pain as both sides have to know the key.

My door access has a key in the card reader which means inherently all cards have to have that key, else the reader has to know the key for each card, which does not scale.

The work around - encrypt the site key with the card UID and use that on the card. One key in reader, different key in each and every cards.

Compromising a card/fob is not easy, but this way it compromises only the one card, not whole site.

#DESFire

@dysfun The #DESFire EV stuff is a big step forward, AES mode even more so. It is not perfect as reader has to have the keys - public key exchanges would be better, but it is so much better than #Mifare classic, or ultralight stuff.

oh uh hashtags for search i guess, so this thread is findable.

#desfire #nfc #orcacard #smartcard