nrf52 - AES decryption possible

[Constantin]

I've read a lot of questions regarding the AES decryption using the nrf51 where it was not possible. Is it now possible with the nrf52 or the even newer version? Thanks,

Constantin

[endnode]

If you ask for HW accelerated AES decryption primitive function then only nRF52840 might have it through ARM CryptoCell. nRF52832 as well as all nRF51 variants lack this HW feature. However you can overcome it through two obvious tricks:

1. Write it in SW (symmetric block ciphers are not so demanding and AES has many open source implementations which can run quite nicely on ARM Cortex-M0 or M4F).
2. Use AES encrypt only and implement some combined encryption/decryption scheme like AES CTR (Counter) mode.

Cheers

[run_ar]

Limited AES example here.

Cryptocell (nRF52840) has a general purpose AES engine, but I'm afrid we only have limited examples for the cryptocell at the time beeing.