can NRF52840 CryptoCell IP act as secure element?

[alireza11048]

Hi to all,

i am developing a device based NRF52840 soc, and i want to implement a device that need to store some public/private key in somewhere. i know that cryptocell ip is an accelerator for cryptographic tasks, but i want to know is this ip  capable of store he keys in the secure space?? if no there is any mechanism in the NRF52840 to store keys??

[haakonsh]

The CryptoCell can store a Device root key in its internal SRAM. And the ACL — Access control lists can block read and/or write access to a region of flash. 

The common use case is to use a secure bootloader to read a key from flash and store it in the cryptocell, then use ACL to block read access to the flash region where the key is stored. 

[alireza sadeghpour]

So this region of memory can be used for storing symmetric/asymmetric encryption keys?

[haakonsh]

Yes, given that you follow the instructions given in my previous answer. 

[Nikos Karamolegkos]

I can not understand, before anything, Is secure to store the key in flash?

[haakonsh]

Depends on your definition of "secure".  

haakonsh said:

And the ACL — Access control lists can block read and/or write access to a region of flash. 

 Though do note IN133 Informational Notice v1.0. Talk to our Regional Sales Manager about device ordering and production programming for nRF52840's with a fix for this issue.