3 ms·

> back doors and opportunity for dystopian political regimes No, this is a misunderstanding of what a TPM is. A TPM is a secure element inside your computer,

by lxgr 2y ago

> back doors and opportunity for dystopian political regimes No, this is a misunderstanding of what a TPM is. A TPM is a secure element inside your computer, similar to the chip running your credit and debit card. That's it. Without you using it (i.e. your OS or an application you installed asking it to do something), it's exactly as dangerous as a blank chip card in your house that you don't use and didn't open any account for. If you don't want anybody to talk to it, don't install applications or OSes on your computer that do things you don't want. You have full control over that! Not running software that's not acting in your own best interests is generally good practice anyway, TPM or no TPM. > [...] a small dedicated hardware element for signing fingerprints is all that's ever been required [...] You might be happy to hear that that's exactly what a TPM is, then!

fc417fc802 2y ago
I am fully aware of what a TPM is. I was speaking about trusted computing - ie the "general purpose attestation capability" that you referred to above. As you say, a TPM alone can't do much of anything and doesn't pose much of a threat. Of course expanding the acronym - Trusted Platform Module - is a bit of a giveaway. They were always fully intended to serve as the root of trust for much more nefarious things.
- lxgr 2y ago
  People keep saying that, yet the only thing I’ve ever seen TPMs used for is full disk encryption and user authentication. Conversely, DRM is alive and well on almost universally TPM-less devices. By the way, all of your comments in this thread end up dead – I had to vouch for them to be able to answer. Not sure what’s up with that.
  - fc417fc802 2y ago
    > the only thing I’ve ever seen TPMs used for is full disk encryption and user authentication. Aren't all device attestation schemes underpinned by authenticated boot which itself is underpinned by a TPM? This is certainly the case for Android - AVB is implemented on top of secure boot on all the devices I've ever owned (and Play Integrity, if I had ever permitted it to run, on top of that). Do I have some misunderstanding about the stack? > Conversely, DRM is alive and well on almost universally TPM-less devices. You mean software DRM I assume? Because the only TPM free hardware backed DRM that comes to mind is GPU based encrypted streams where the GPU does the decoding and final compositing locally. And even then the TPM-equivalent exists, it just isn't accessible to the end user. SGX can be used to do various interesting things without attesting the state of the broader system, but none of the examples that immediately come to mind feel much like DRM to me. > comments in this thread end up dead Thanks for letting me know. I guess I should email them?

by lxgr 2y ago

fc417fc802 2y ago

I am fully aware of what a TPM is. I was speaking about trusted computing - ie the "general purpose attestation capability" that you referred to above. As you say, a TPM alone can't do much of anything and doesn't pose much of a threat. Of course expanding the acronym - Trusted Platform Module - is a bit of a giveaway. They were always fully intended to serve as the root of trust for much more nefarious things.

lxgr 2y ago
People keep saying that, yet the only thing I’ve ever seen TPMs used for is full disk encryption and user authentication. Conversely, DRM is alive and well on almost universally TPM-less devices. By the way, all of your comments in this thread end up dead – I had to vouch for them to be able to answer. Not sure what’s up with that.
- fc417fc802 2y ago
  > the only thing I’ve ever seen TPMs used for is full disk encryption and user authentication. Aren't all device attestation schemes underpinned by authenticated boot which itself is underpinned by a TPM? This is certainly the case for Android - AVB is implemented on top of secure boot on all the devices I've ever owned (and Play Integrity, if I had ever permitted it to run, on top of that). Do I have some misunderstanding about the stack? > Conversely, DRM is alive and well on almost universally TPM-less devices. You mean software DRM I assume? Because the only TPM free hardware backed DRM that comes to mind is GPU based encrypted streams where the GPU does the decoding and final compositing locally. And even then the TPM-equivalent exists, it just isn't accessible to the end user. SGX can be used to do various interesting things without attesting the state of the broader system, but none of the examples that immediately come to mind feel much like DRM to me. > comments in this thread end up dead Thanks for letting me know. I guess I should email them?