[XorNot]

Partly because these systems are designed to destroy the data if not unlocked. Your "plausible" container, if not unlocked, makes the rest of the container look like free space - i.e. destroyed by an OS not aware it shouldn't write to it.

Which is common with HDD block-device format containers (not sure this thing makes as much sense) anyway: if my laptop here (which is encrypted) gets unlocked with 2 passwords, you would need to independently verify that in fact I normally used 3 and the idea is you can't prove that the "free space" is actually not just normal freespace on my HDD.

Combined with a TPM chip and not having any recovery codes and the HDD can't be realistically extracted except by nation-state level actors with a motivated interest.

Also why would "truly secret" data be large in size to start with? The more likely relationship would be 100:10:1 or greater in terms of "plausible" to "implausible".

[dane-pgp]

> and not having any recovery codes

An alternative might be to use something like Shamir's Secret Sharing to split the recovery codes between a dozen mutually-unknown friends in different jurisdictions, such that the secrets held by some threshold of them could produce the recovery codes.

These friends would have to be trusted to only hand you their share if they meet you in person in their jurisdiction, and should perhaps also first tweet out that they were doing so, in order to warn anyone whose security might depend on your encrypted data not being compromised.

[XorNot]

Well the data is going to get wiped after you unlock without enough passphrases anyway, so it's kind of pointless - you need a backup. The point of not having recovery codes for the TPM is to ensure the disk is completely unusable if the machine is tampered with - i.e. you have to be forced to unlock that machine, and not a copy, to ensure the data is destroyed. I do wonder if TPM's would detect the use of SATA/PCI-E write blockers (or some elaborate shim system - but again, nation-state level).

Of course this is the real fiction: in reality I'm somewhat too lazy to set all that up for the much more likely scenario of a preventable glitch hosing my system.

[qwerty456127]

> you can't prove that the "free space" is actually not just normal freespace on my HDD.

Isn't normal free space supposed o contain at least partially recoverable traces of deleted files usually? I think we need a file system that wipes everything deleted (including file names!) and replaces it with random data by default.