Implementing additional security using software
Refer to Appendix A and Appendix B in the Threat Models and Security Analyses for three common IoT use cases. For each case, Appendix A details which of the required security functionality is covered by the CryptoIsland product. Appendix B details which of the required security functionality is covered by Arm TrustZone technology. Try to see where your own secure IoT device has the same requirements and identify what technology would cover it.
In cases where CryptoIsland does not cover a security functionality, Trusted Firmware-M might provide the functionality. For example, CryptoIsland does not offer hardware support for maintaining an audit trail of security events, but the Trusted Firmware-M (TF-M) provides this feature.