Cryptocell and future products vs MicroECC

[SRA]

So... As I understand it, micro-ECC is a free library that lets you create an ECC private key for signing the SecureDFU that Nordic is using.

The nrf52840 has Cryptocell 310 which has ECC hardware.

To the best of my ability to check this, they are not using compatible curve profiles. Doesn't it make the most sense that one of the curve options used in the hardware reflects the curve options used for Nordic software?

[bjorn-spockeli]

Hi SRA,

at the current moment our Secure DFU implementation only supports the NIST P-256 curve for the simple reason that the Bluetooth Core Specification also uses the P-256 curve for LE Secure Connections. We may add support for other curves, like the Curve25519, in our Secure DFU implementation in the future.

As for Cryptocell, we also currently do not have any support for that in the Secure DFU implementation yet, but that may also change in the future.

Best regards

Bjørn

[SRA]

Ok, so I wasn't wrong. The Cryptocell is currently incapable of generating the correct curve for SecureDFU. Yes, I would like to see a more standard according to ARM at least curve profile used in firmwares. Like p256 dropped entirely in SecureDFU and curve25519 used instead.