Hi Bahutan,
I should have explained that indeed, I am sorry. Inside the Nitrokey Pro resides a OpenPGP Card v3.3. So technically you can do everything what a OpenPGP Card v3.3 can do. Therefore, I linked the specification.
As this is a rather new feature there is no software which makes use of this functionality. OpenSC is not able to handle this yet and I don’t know if it will (didn’t looked at it from a AES perspective in the past), but it is a good candidate.
In summary: there is no solution for that yet, but the Pro 2 supports enciphering and decryption with a imported AES key. The operations are done on the Nitrokey. So this would be what you are looking for. I would implement such feature in OpenSC (if desired by the project), but can not do it anytime soon.
Kind regards
Alex