[mschuster91]

> The problem here is that the signature doesn't do anything for you.

For your own personal machine, sure. But say you're a sysadmin in a company that has thousands of units. Suddenly, a CA infrastructure is much more appealing than having to deal with component hashes.

[AnthonyMouse]

How is it any different? You install the hash of the boot loader when you issue the machine, then use the trusted system to update the hash if necessary.

Also, the concern is that the system comes from the factory with private keys the owner doesn't have access to, allowing the device to defect by informing on them to a third party. Keys installed by the owner rather than the manufacturer are fine, and then such keys also wouldn't be trusting random third party code either.

[mschuster91]

> How is it any different? You install the hash of the boot loader when you issue the machine, then use the trusted system to update the hash if necessary.

With your private CA you can skip the "update the hash" part, removing a crucial step that one might forget in a hurry or that simply might go wrong because of whatever sort of bug or power outage... and brick thousands of machines as a result.

[AnthonyMouse]

The "update hash" part is the counterpart to the "sign the binary" part, so if you forget to do it you're going to have problems either way. Also, this is the sort of thing that large organizations would have automated tooling to do anyway.

[mjg59]

If a device is running code you control, how does it defect?

[AnthonyMouse]

If you can't make it do something you don't want it to do, someone else can't pressure you to do it.