RE: How to implement ECC functions on SDK v12.3.0 and nRF51822

Ethan.jskim — Thu, 02 Aug 2018 00:46:12 GMT

Very Thanks Einar.

Your answer is very helpful to solve my problem.

RE: How to implement ECC functions on SDK v12.3.0 and nRF51822

Einar Thorsrud — Wed, 01 Aug 2018 08:08:18 GMT

Hi,

The Relevant changes in nRF5 SDK v15.0.0 section in nWP031 - Security Threat in Bluetooth LESC Pairing describe the changes made for SDK 15, and you should do the same for older SDKs.

Using the Experimental: BLE LE Secure Connections multirole example from SDK 12.3 as a reference, you should update the handling of the BLE_GAP_EVT_LESC_DHKEY_REQUEST request in main.c. There you should validate the remote peer public key and only calculate the shared secret if it is valid. If it is invalid, return a random shared secret to make pairing fail.

I have made some modifications to the example main.c here, which uses uECC_valid_public_key() from micro-ecc via wrapper functions that I have added in the ECC interface module in the SDK (below).

Diffs only:

devzone.nordicsemi.com/.../main.c.diff

devzone.nordicsemi.com/.../ecc.h.diff

devzone.nordicsemi.com/.../ecc.c.diff

Complete source files: devzone.nordicsemi.com/.../lesc_5F00_fix.zip

RE: How to implement ECC functions on SDK v12.3.0 and nRF51822

Ethan.jskim — Wed, 01 Aug 2018 02:55:13 GMT

I found myself an answer to this question.

I will close my question by myself.