nrf9160 Modem Firmware Crypto Hardware Support

[JD Scott]

Hi there,

I'm looking for more clarification on the following post regarding cryptographic HW acceleration in the nrf9160 radio core:  Which elliptic curves are supported by the nrf9160 modem? .

There is this comment:

There is no asymmetric cyrpto HW acceleration in the modem, correct? That seems to imply that symmetric crypto is supported (e.g., AES). If this is the case, is this documented officially anywhere in release notes or Product Specifications for the nrf9160?

Thanks,

JD

[Amanda Hsieh]

Hi, 

See nRF9160PS/CRYPTOCELL — ARM TrustZone CryptoCell 310

Regards,
Amanda H.

[JD Scott]

Thanks for responding, Amanda. That does list that a CryptoCell is available in the nrf9160 but do the LTE Modem FW  releases for the SiP modem firmware (e.g., the latest being version 1.3.5) leverage this hardware for things like TLS handshakes? We're looking to lower our power consumption. If HW acceleration is not utilized here, we may look at offloading TCP to the nrf9160 application core to use the CryptoCell.

I question if hardware acceleration is enabled because `ed25519` is listed as supported in the CryptoCell documentation you provided, but is not listed as a supported ECC group in the TLS `Client Hello` message from the nrf9160.

Thanks again

[Amanda Hsieh]

Hi, 

nRF9160PS/CRYPTOCELL — ARM TrustZone CryptoCell 310 is in application domain's use, not in modem’s use.

The Modem’s TLS stack uses HW acceleration only for AES. 

-Amanda H.

[JD Scott]

Hi Amanda,

Is this documented anywhere in which I can reference for our internal project documentation?

Thanks,

JD

[Amanda Hsieh]

Hi James,

Unfortunately, this is not documented in any public document. 

You are free to try TCP offloading to appcore to see if it improves performance over our native TCP implementation in Modem. Both are viable options but we only support native TCP on our Modem and appcore trials are your own responsibility.

-Amanda H.