Getting started with RNG and Crypto

[wdtj]

We need to do some crypto.  The first task being to generate a random number with rng. I have been fighting through the sdk_config.h defines, and the list of modules that need to be added to our build for the nRF52840 and ended up with a module that gets to the cc310_backend_rng.c, calls CRYS_RndInit and simply reboots.

So I go to the example in nrf5_sdk\examples\crypto\nrf_crypto\rng.  That won't build on IAR, it ends up with a build error:

Error[Lt009]: Inconsistent wchar_t size 
            ssi_aes.c.obj(libnrf_cc310_0.9.13.a) and 64 other objects in libnrf_cc310_0.9.13.a have wchar_t size 16 bits 
            aes.o and 187 other objects, some of them in dl7M_tlf.a and 13 other libraries have wchar_t size 32 bits 

Is there a document somewhere that explains "getting started with RNG on the nRF82840"?  What RNG backend should I be using?  Which defines should I be setting?  What source is required? 

Were using IAR 8.50.9.33462, nRF5 Software Development Kit v17.1.0, and a custom board with a MAXQ1065. 

[wdtj]

Thanks for the tip to use the non-short-wchar library from the SDK release notes.  This solved the issue with getting the rng example to build.  With the rng example, I found that I was missing a call to SaSi_LibInit() before calling nrf_crypto_init.  I then tripped over the issue in nrf_crypto_init ERROR Initialization or startup of RNG failed.  I'm now happily generating random numbers.

Thanks again.

[ovrebekk]

Good to hear you got it working, I will close the ticket then