Hi Siewie,
Welcome to the wolfSSL Forums. We encourage users to send an email to support@wolfssl.com in order to receive the highest priority support.
Here is a short RSA example that will give you an idea of the intended usage:
https://github.com/wolfSSL/wolfAsyncCry … sa-example
> (2) Is it correct that any hash function callback provided through "wc_CryptoCb_RegisterDevice" must be blocking?
No, the callbacks can be implemented as non-blocking, and utilize the async features.
> (3) It appears like we could improve the performance a lot by using the WOLFSSL_SP_ARM_CORTEX_M_ASM option. However, the non-blocking implementation is not available. Concretely, we are missing the definition of struct sp_256_ecc_mulmod_8_ctx and the function sp_256_ecc_mulmod_8_nb (wolfcrypt + wolfasynccrypt v5.6.6).
I'll check with the team on this question.
Thanks,
Eric - wolfSSL Support