How good are data encryption in nrf52832, nrf52840 NUS?

[TAEYOUNG]

Hello

I am a product development team leader and mobile (iOS, Android) app developer.

Our product uses NUS to control the product.

Currently, encryption is not applied, so to strengthen security
We are reviewing encryption for data sent to and from NUS.

We leave this to ask what technology you mainly adopt when encrypting.


note
1. The product runs on battteris.
2. test chip : nrf52832, nrf52840
3. I was considering "AES-CCM".
However, the device developer has responded that the technology consumes a lot of battery and is not good for performance.


Thanks for reading.

[Hung Bui]

Hi Choi, 

Our security experts are on vacation but I will try to help you in the mean time. 

The most common encryption we suggest is to use the Bluetooth's pairing encryption which is AES-CMAC (AES-128) and P-256 elliptic curve. This takes the advantage of hardware support on the radio hardware so it will reduce the power consumption as you don't need to use the CPU for the encryption and decryption. 
After the introduction of LE Secure connection, the P-256 elliptic curve is used to generate the encryption key and by today standard the pairing process can be considered secure. LE Secure connection is supported by most phones Bluetooth stack now aday. 

Of course you can put an extra layer of encryption on top of Bluetooth pairing but it will come to the challenge on how you exchange the keys or use hardcoded key which may not be the best option. 

Could you give us some more information about the power consumption draw back that you found when testing with AES-CCM ? 

[TAEYOUNG]

Thank you for your quick reply.

We will respond after reviewing the method you suggested. 

Happy new year.

[TAEYOUNG]

I'm sorry if I misunderstood something.

The problem was not that the performance of the device was degraded, but that the amount of memory of the chip was insufficient.

Thank you for good information.