SE051 Key Diverisification Algorithm

trink185 — Tue, 25 Feb 2025 20:07:17 GMT

Hello,

I have an SE051 which I am storing symmetric keys on. I am using the Plug and Trust Nano-Package, and am building an app using Zephyr.

Generally, I am able to use the SE051 and the Nano Package in order to generate and use diversified keys on the SE051.

However, I was wondering, am I able to change the algorithm on the SE051 by which keys are diversified? My understanding based on AN12543, is that keys are diversified in a means described by AN10922.

Is there a way to change this? Or is the method described in AN10922 the only way the SE051 can diversify keys?

Thanks!

Re: SE051 Key Diverisification Algorithm

Kan_Li — Wed, 26 Feb 2025 06:15:42 GMT

Hi @trink185 ,

The algorithm on the SE051 to diversify key is fixed, but of course you may determine which key to be diversified. AN12543 addresses this explicitly as below:

Create a Diversified Key according [AN10922]. Input is divInput of 1 up to 31 bytes.
Note that users need to create the diversified key object before calling this function.

It is also recommended creating the diversified key object as a transient object to avoid memory consumption.

Hope that helps,

Have a great day,
Kan

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Smart Cards and Secure ElementのトピックSE051 Key Diverisification Algorithm

SE051 Key Diverisification Algorithm

Re: SE051 Key Diverisification Algorithm