Hello,
I'm evaluating the use of wolfCrypt for ECDSA signature verification using the secp256r1 curve on a 16-bit microcontroller. My goal is to achieve this using only configuration options, without implementing custom math routines.
I've selected the Integer Heap Math backend (USE_INTEGER_HEAP_MATH), as it appears to be the most compatible option for my platform. However, I'm encountering issues with the optimized ECC verification helper function ecc_verify_hash_sp, which is automatically enabled via HAVE_ECC_VERIFY_HELPER when no hardware ECC macros are defined.
This function seems to lack an implementation suitable for my platform, and disabling HAVE_ECC_VERIFY_HELPER leads to compilation errors due to undeclared variables like sigRS.
Could you please advise:

Whether ECDSA secp256r1 verification is feasible on 16-bit platforms using only configuration (without custom math)?
If so, what is the recommended way to configure the library to bypass ecc_verify_hash_sp and ensure compatibility?

Thank you!