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A TPM integrated into the CPU makes sense (and I am puzzled why TPMs aren't a standard feature of all MB given the modest cost). But what about that diagram in
by cm2187 6y ago
A TPM integrated into the CPU makes sense (and I am puzzled why TPMs aren't a standard feature of all MB given the modest cost). But what about that diagram in the article with a link to the cloud? Will this thing phone home outside of the control of the OS?
- darzu 6y agoIn Azure Sphere, Pluton didn't do any direct network communication, that was all handled by the main core. Also there was no cellular so the whole system depended on user interaction to get online. When the main core wanted to talk to the Azure Sphere cloud service (from Linux user land), it would go through a remote attestation process that involved Pluton. Pluton can securely track what software was booted on the main core (called "measure boot") and it basically sends a hash of that to the cloud to prove to the cloud what software is currently running. So I imagine the chip-to-cloud thing they're talking about is this remote attestation protocol. Also, it's possible the term "Pluton" has been expanded to refer to more than just the M4 chip we used in Azure Sphere.
- josh2600 6y agoI guess I’m wondering how Pluton and SGX coexist...
- xenocratus 6y agoFrom what I understand, Pluton is more in the vein of TPMs, so able to store and handle your cryptographic keys and to do measurements during your boot process. SGX is a hardware feature that allows an app to run securely (i.e. Without any possible interference from other apps or even the OS) in a hardware-enforced enclave. Completely different tasks and use cases, which might overlap - maybe you can use keys with Pluton from within an SGX enclave?
- Mindwipe 6y agoI think you should assume Pluton will be used instead of SGX, which is so broken nobody has any confidence in it any more.
- antman 6y ago" it basically sends a hash of that to the cloud to prove to the cloud what software is currently running." oh dear
- floatboth 6y agofTPMs have been standard for a few years now. As I understand it, this Pluton thing is mostly about having a fully "hardware" TPM inside the SoC instead of a "firmware" one.
- als0 6y agoIt's a mix. The keystore is apparently in hardware but there is Pluton firmware to manage it.
- floatboth 6y agoYes, of course management firmware is everywhere. Having keys in special memory that is literally only connected to fixed-function crypto HW blocks is what makes something a "hardware" security thing.