NXP has a custom (I think) encryption protocol known as "Leakage-Resistant Primitive", or LRP, built on top of AES. I think the goal of this is to basically "expand" the length of the key being used. This is used on devices that have 128-bit keys, and, from what I can tell, LRP basically takes a 128-bit key and expands it to a 16,384-bit key. I think the reason for this is because NFC cards typically use 128-bit keys, because they have an limited write memory.

Does anyone know how effective LRP is at getting beyond the small key size, or any other benefits/drawbacks of using LRP?

LRP is described in this document:


You can view an implementation of LRP here:




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