Replace Oberon backend with uECC backend in LESC device app

RE: Replace Oberon backend with uECC backend in LESC device app

user116355 — Tue, 24 May 2022 15:48:21 GMT

Hi Vidar,

I failed to understand correctly your initial answer.

After reading again and again the crypto backends related documentation I was sure that you mentioned the compilation flags to be used while building the uECC library. But after I looked more carefully I see that the same flags have to be used also in the project using the uECC library. And that is because uECC_VLI_NATIVE_LITTLE_ENDIAN flag is also used by the micro-ecc backend which is compiled as a part of the project.

Please update the documentation of the backend.

Now while compiling my project with uECC the pairing works.

Thanks,

Ron.

RE: Replace Oberon backend with uECC backend in LESC device app

user4240 — Tue, 24 May 2022 12:33:04 GMT

Hello Ron,

[quote user="Ron."]I see no issue here, it is probably something else.[/quote]

Probably. But I'm not really sure what it could be considering uECC is just another backend for nRF crypto (i.e. should only be a matter of changing some config. settings)

Please try to run the project below and see if you get the same result. It's a modified version of the ble_app_hrs example from SDK 16 that I made to test out LESC pairing with uECC instead of Oberon. It did not get any pairing failures when I tested it at least.

test-devzone.nordicsemi.com/.../ble_5F00_app_5F00_hrs_5F00_uecc_5F00_lesc.zip

Best regards,

Vidar

RE: Replace Oberon backend with uECC backend in LESC device app

user116355 — Mon, 23 May 2022 13:39:06 GMT

Hello Vidar,

Please see the flags I use to build the uECC library:

uECC_ENABLE_VLI_API=0

uECC_OPTIMIZATION_LEVEL=3

uECC_SQUARE_FUNC=0

uECC_SUPPORT_COMPRESSED_POINT=0

uECC_VLI_NATIVE_LITTLE_ENDIAN=1

I see no issue here, it is probably something else.

Best Regards,

Ron.

RE: Replace Oberon backend with uECC backend in LESC device app

user4240 — Mon, 23 May 2022 13:21:52 GMT

Hello,

Please make sure you are building your project with these uECC_* flags like in the ecdh crypto example (/examples/crypto/nrf_crypto/ecdh)
:

The last symbol highlighted in read is the most important one. Without it, the nrf crypto library will assume the uECC backend is big endian like the others and cause computation of the shared secret to fail.

Best regards,

Vidar

RE: Replace Oberon backend with uECC backend in LESC device app

user116355 — Sun, 22 May 2022 19:26:31 GMT

I forgot to mention that the projects are built with nRF5 SDK 16.0.0