nrf_crypto_init finds no backend in SDK15

Question

Hi, 
 I have the problem, that nrf_crypto_init() does not find any backends and thus is skipping the initialization. 
 What is the precondition for NRF_CRYPTO_BACKEND_SECTION_ITEM_COUNT to find a backend? 
 I enabled NRF_CRYPTO_BACKEND_MICRO_ECC_ENABLED and NRF_CRYPTO_BACKEND_NRF_HW_RNG_ENABLED in the sdk_config.h. 
 I tried the ble_app_multirole_lesc example, where NRF_CRYPTO_BACKEND_OBERON_ENABLED and NRF_CRYPTO_BACKEND_NRF_HW_RNG_ENABLED are enabled. 
 This returns num_backends=1, but i don't know why this is not working for MicroEcc. 
 
 Also should nrf_crypto_init() really return NRF_SUCCESS in this case? It skips the entire initialization if num_backends = 0 but still sets m_state to INITIALIZED; 
 Best regards, 
 Niclas

Vidar Berg · Accepted Answer

Hi Niclas, 
 Section variables are used to register init/uninit functions for backends that require initialization. Registration is done with the CRYPTO_BACKEND_REGISTER() macro. nrf_crypto_init() will then iterate through these and call the init functions that have been registered. 
 uECC backend does not require initialization but the NRF HW RNG backend does so I would have expected the number of backends to be '1' in your case. Is nrf_hw_backend_init.c included in your project? This is where the init function gets registered. 
 Best regards, 
 Vidar

nrf_crypto_init finds no backend in SDK15

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