> Emulating a TPM at the hardware level is possible but too much work
good for us that amd does it for free, huh? https://www.amd.com/en/technologies/pro-security (fTPM)
Where do the keys get strored? Flash in the CPU? UEFI variables? A second flash chip on the motherboard?
it depends amd mostly uses its psp (platform security processor) of course security depends on amd's enclave. it basically uses ARM TrustZone, microsoft explained it in a paper: https://www.microsoft.com/en-us/research/wp-content/uploads/... so the internal storage is eMMC with RPMB and a hardware fuse
Emulating a TPM at the hardware level is possible but too much work when you can just buy the chips themselves--they aren't some magic unobtanium locked down thing, for example: https://www.digikey.com/catalog/en/partgroup/trusted-platfor...
The problem is to get an old system to use it you'd have to also modify its bios to make it aware of the TPM (and figure out how to get access to the phsyical bus the TPM needs to interface with the motherboard). There is a lot of reverse engineering and work to do that sort of thing.