Which is best candidate out of nrf52840 & nRF52832 for BluetoothMesh n/w for security point of view ?

[vikrant8051]

> This is highlight of difference
> between #nrf52840 & #nRF52832.
> 
> #nRF52840 has additional feature of ARM CryptoCell. 
> 
> Is this make #nRF52840 more secure for
> #IoT or #BluetoothMesh application where security of network is more
> important ?

[vikrant8051]

I don't know what to say on this !! Need help from person who has already worked with nrf52840's CryptoCell.

blog.bluetooth.com/bluetooth-mesh-security-overview

Is cryptocell necessary, even when #BluetoothMesh specification added different layers of security by default ?

[endnode]

ARM Cryptocell or Trustzone has pretty much nothing to do with BT SIG mesh network specification if this is your question. CC310 can help you to achieve two things: having certain crypo schemes with better performance (= computing crypto operations faster) and potentially design your FW securely (thanks to "privileged" mode when you can restrict which code will run on MCU at what moment - exclusively). However you can see implementations of BT SIG mesh on common ARM Cortex-M chips without any specific security features (or even on C51 8-bit clones) so it doesn't harm the functionality of "mash" itself. Btw. you haven't mentioned what mesh architecture/specification you are talking about so I assume you talk about BT SIG standardized mesh network but there are many others... again it indicates to me that you are more going for buzzwords and stickers then knowing exactly what you need.

[vikrant8051]

Your assumption is right. I am talking about latest Bluetooth_SIG Mesh Specification released in July 2017.

www.bluetooth.com/.../mesh-specifications

So in simple words, I can go with nrf52832 assuming Bluetooth_SIG specification has take care of security inherently.

Pricing of nrf52832 is surely less than nrf52840. Even Silvair like company is using nrf52832 for their product. So my goal is to finally launch product based on nRF52832 to save overall cost.

[endnode]

Yes, the summary fits my view. Still your comment "Bluetooth_SIG specification has take care of security inherently" indicates that you are taking too many assumptions about how real world attacks and securing embedded devices work, kind of foggy cloud named "security" (someone will put a stamp on it and voila it's solved;)... but maybe I'm totally wrong. Good luck!

[ovrebekk]

Hi

The current implementation of Bluetooth mesh does not use the Cryptocell module, and we have no immediate plans of adding support for it. In other words, there are no changes to Bluetooth mesh security whether or not you use the nRF52840 or the nRF52832.

As you hint at in the comment the nRF52840 is overkill for many mesh applications, and we expect the nRF52832 to be a more popular choice.

We can implement all the security requirements of the Bluetooth mesh specification without it. The main advantage of using the Cryptocell when it's available is that the crypto algorithms run quicker, which can reduce latency and power consumption.
Since the radio is on continuously when using mesh the power consumption is pretty high already, and the improvements by using Cryptocell would most likely be marginal.

Best regards
Torbjørn Øvrebekk