When I wrote that I definitely debated whether to include tpm in the list because of concerns along those lines. But in the end it's a widely deployed example o

When I wrote that I definitely debated whether to include tpm in the list because of concerns along those lines. But in the end it's a widely deployed example of that type of technology which makes it a good example. It definitely wouldn't be my first choice in any case just due to the complexity of it - there is > 10k loc inside your typical tpm as i understand it. One thing to keep in mind though is that tpm is a spec/standard that's been implemented by several different vendors. They're the ones that write the code that goes inside as it was considered an implementation detail in the spec. So that means you can buy a german tpm (infineon) or a french tpm (stm) or a us tpm (intel, atmel?) and so on including taiwan and china. So you can sort of pick your poison, presumably they aren't exactly sharing their backdoors with each other at least not france+us+china. Even assuming it's a compromised platform it's still a hell of a lot more likely to keep your key material safe as compared to having it sit on disk or in addressable address space. One presumes backdoors like that are used sparingly as they become considerably less valuable once publicly exposed.