Hi @DGB
To provide a certificate, the HSE supports the option to "import standard key certificates", in this case, the key container of the Key to be imported is formatted according to a standard certificate format. To properly import the key, the host must provide the pointers to the key values and container within the certificate. If we were working with an RSA public key provided as an RSA-signed X.509 certificate we must distribute the information as mentioned in section 6.2.3.6 (Importing standard key certificates) of the HSE_B Firmware Reference Manual.
You can refer to Mbed TLS which is a C library that implements cryptographic primitives, X.509 certificate manipulation, and the SSL/TLS and DTLS protocols. What we provide can be downloaded from S32K3 Reference Software > Automotive SW - S32K3 - mbedTLS.
B.R.
VaneB