On Tue, May 14, 2024 at 4:54 PM James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, 2024-05-14 at 16:38 +0100, Ignat Korchagin wrote: > > On Tue, May 14, 2024 at 4:30 PM James Bottomley > > <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > On Tue, 2024-05-14 at 14:11 +0100, Ignat Korchagin wrote: > > > > * if someone steals one of the disks - we don't want them to > > > > see it has encrypted data (no LUKS header) > > > > > > What is the use case that makes this important? In usual operation > > > over the network, the fact that we're setting up encryption is > > > easily identifiable to any packet sniffer (DHE key exchanges are > > > fairly easy to fingerprint), but security relies on the fact that > > > even knowing that we're setting up encryption, the attacker can't > > > gain access to it. The fact that we are setting up encryption > > > isn't seen as a useful thing to conceal, so why is it important for > > > your encrypted disk use case? > > > > In some "jurisdictions" authorities can demand that you decrypt the > > data for them for "reasons". On the other hand if they can't prove > > there is a ciphertext in the first place - it makes their case > > harder. > > Well, this isn't necessarily a good assumption: the way to detect an > encrypted disk is to look at the entropy of the device blocks. If the > disk is encrypted, the entropy will be pretty much maximal unlike every > other use case. The other thing is that if the authorities have your What if the disk is filled with random data? Would it not be at maximal entropy? > TPM, they already have access to the disk in this derived key scenario. I'm thinking more of a datacenter scenario here - it is much easier to "steal" a disk rather than a server from a datacenter. So it is possible that someone has the disk but no access to the TPM. > If *you* still have access to your TPM, you can update the storage seed > to shred the data. The point here is not if I was able to shred the data or not, but the fact I have something encrypted. Even if I shred the key I would be considered "uncooperative and refusing to provide the key" vs "I don't have anything encrypted in the first place". > James >
