ECC Point Multiplication in CC310

[chirag-parmar]

How can I do a point multiplication in NRF52840 using the ECC hardware accelerator for the secp256k1 curve? Also are there examples or any documentation on how to implement this?

The END GOAL is to calculate a public key from a known private key for ECDSA algorithm.

[Einar Thorsrud]

Hi,

The ECC hardware in the nRF52840 is part of the CryptoCell peripheral, which is accessible via the CC310 runtime library. In most cases using the nrf_crypto library is a simpler approach, and this can use CC310 as one of the multiple backends. Then you can simply use the nrf_crypto_ecc_public_key_calculate() function to calculate the public key from the private key.

[chirag-parmar]

public key calculation is not possible for the secp256k1 curve. I found this out by diving into the SDK source code, particularly `cc310_backend_ecc.h`.

#define nrf_crypto_backend_secp160r2_public_key_calculate NULL

After reading through the entire file I found out that public key calculation is not supported for any of the curves. I am disappointed about this because the CC310 has ECC math accelerators built in it but can't be used.

What I want to know is if there is a work-around for this (without using software backend)?