MIFARE DESFire authentication

[tristar]

Hi,

I have a question regarding the AES authentication method used in MIFARE DESFire EV1. Two random values are used, RndA and RndB. Both values must be rotated by one byte in the reader and in the card. My question: for what this shift is used for? Does it increase the security? It is done at the plain values and both values are random. So, how can I increase security if I shift random values by one byte?

Thanks in advance

[Jonathan_Iglesias]

I am going to direct message you with the answer to this topic.

BR

Jonathan