ECC Calculation Example with Nitrokey Start

chraymond · November 30, 2021, 4:00am

May I know if there is any example on how to integrate Nitrokey Start to trigger the ecc calculation functions?

szszszsz · November 30, 2021, 10:44am

Hi!

You can use GPGME, which is a C API to GnuPG.
In case you would like to run it directly, you can sniff the traffic exchanged in step 1, or look into the specification itself:
- https://gnupg.org/ftp/specs/OpenPGP-smart-card-application-3.4.pdf
- https://gnupg.org/ftp/specs/OpenPGP-smart-card-application-2.0.pdf

Note: This spec is describing version 3.4. Nitrokey Start is implementing fully version 2.0, with some extensions taken from 3.4, notably the ECC support for selected algorithms.

szszszsz · November 30, 2021, 10:55am

I think someone has used Nitrokey Start / GNUK as a Bitcoin wallet too as far as I remember, so perhaps you could find some related code in a web search.

chraymond · December 1, 2021, 6:18am

Thanks for sharing, my plan is not only doing the signing, I want to trigger those modp256k1_sub/modp256k1_add/modp256k1_mul and edward related functions indeed and it is difficult to find related example on the web.