before the popularity of ARM SoCs that contain everything on-die there were much fewer choices for vertically integrated devices. it's a different segment. if

before the popularity of ARM SoCs that contain everything on-die there were much fewer choices for vertically integrated devices. it's a different segment. if you look at apple's vertically integrated devices, they chose a cryptography coprocessor that was not on die originally. with a key accessible only by both pieces of silicon's trusted execution environments, rather than the operating system directly, encrypted comms are established in a similar fashion as the TPM2.0 proposal.