> Leaking the master key (and it will leak) exposes everyone
I agree that it should be assumed that the key will leak but there are plenty of ways to practically mitigate the usefulness of a leaked key.
I mentioned expiring keys already, which is obvious, but there are more sophisticated protocols that can be put in place.
> The target is much bigger, the payoff is much bigger for the bad guys
I don't think this is true. These keys would only be usable with physical access to a device. If you have physical access to the device its hard to imagine a scenario where the easiest route to cracking it would be penetrating a secure government facility.
Let me add that you have to think about security in relative and not absolute terms.
If you trust the government to secure a massive stockpile of NBC weapons, if you trust the government to manage a massive state security apparatus with hundreds of thousands of armed agents deployed domestically, then it is a little silly to draw the line at trusting them with your facebook feed.
> If you trust the government to secure a massive stockpile of NBC weapons [etc]
Physical security and digital security are very different. Someone stealing a bomb is still only one bomb. Securing that bomb involves fortifying a well-defined local border. Attacking it requires personal risk that is hard to parallelize.
Digital networks can be attacked at any time from any number of opponents. These attacks are usually automated without the risk of being found by a guard with a machine gun. Stealing the escrow key database isn't merely a single bad event; it would allow access - possibly retroactively - everything supposedly protected by those key, which is presumably "everything".
> key
You seem to be using "key" to mean several different concepts.
I agree that it should be assumed that the key will leak but there are plenty of ways to practically mitigate the usefulness of a leaked key.
I mentioned expiring keys already, which is obvious, but there are more sophisticated protocols that can be put in place.
> The target is much bigger, the payoff is much bigger for the bad guys
I don't think this is true. These keys would only be usable with physical access to a device. If you have physical access to the device its hard to imagine a scenario where the easiest route to cracking it would be penetrating a secure government facility.
Let me add that you have to think about security in relative and not absolute terms.
If you trust the government to secure a massive stockpile of NBC weapons, if you trust the government to manage a massive state security apparatus with hundreds of thousands of armed agents deployed domestically, then it is a little silly to draw the line at trusting them with your facebook feed.