https://devzone.nordicsemi.com/f/nordic-q-a/17598/problem-with-ecc-cHi, I&#39;m working on a BLE application which use ECC.c (Elliptic Curve Crytography). The problem is Keil has found an Error: ._build\nrf52832_xxaa.axf: Error: L6218E: Undefined symbol nrf_drv_rng_block_rand (referred from ecc.o). if i remove theen-USTelligent Community 13Tue, 08 Nov 2016 09:48:12 GMThttps://devzone.nordicsemi.com/thread/67676?ContentTypeID=1Tue, 08 Nov 2016 09:48:12 GMT137ad170-7792-4731-bb38-c0d22fbe4515:29ca75cd-cb8b-46ce-a711-d1a2ecd6da71Maxim<p>Yes, i&#39;ve forget to include this file and check RNG_Enabled in sdk_config.h. Thank you very much !</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/67675?ContentTypeID=1Tue, 08 Nov 2016 09:04:59 GMT137ad170-7792-4731-bb38-c0d22fbe4515:abf3152f-cf98-4afb-bc94-9b48258a22d5J&#248;rgen Kvalvaag<p>Did you forget to include the nrf_drv_rng.c in your project? It&#39;s located in components\drivers_nrf\rng\nrf_drv_rng.c.</p><div style="clear:both;"></div>