On Mon, 2014-06-16 at 12:01 +0000, Thorsten Glaser wrote:
> You completely miss http://xkcd.com/538/ and the fact that some
> legislations may require you, with jail penalty, to hand over
> any encryption keys, passwords, etc. you have with you when
> inside their territory.
Quoting the man page:
"Following these instructions ensures your password is not the
weakest link in the chain. In reality this won't stop an attacker,
they will just move their attention to the next weakest link. Avoid
malware, dementia, rubber hoses, and the UK."
That aside, the rubber hose is mostly an orthogonal problem. What you
are really trying to protect against isn't someone just stealing your
keys. By itself it isn't sufficient to do real damage. The attacker
needs something more: they have to steal your keys without you knowing.
This was demonstrated when a DD had to forfeit his laptop recently. The
project found out almost immediately, and the loophole was closed before
it could be exploited. The situation is similar if you have your credit
card details stolen, or banking credentials leaks, or you lose your
bitcoin wallet. Once you find out about it the risk period ends. Ergo
if you know about it immediately there is almost no risk, period.
So the rubber hose comic is funny, but is also misleading. After all if
someone has hit you about the head with a rubber hose the odds are high
you will know he's done it. But if someone gets hold of your encrypted
secret key and brute forces the password, you won't. And if you don't,
you are looking at the possibility of someone install back doors into
Debian for years. Yes, it is a black swan event - but they only need
one.
Unfortunately getting hold of the encrypted key is made easier because
because we have to back the damned things up. If we do it properly, we
have created multiple copies, distributed them across separate
geographic localities, probably in different countries.
The only thing protecting those backups is the password.
If you have read this far, I hope you now understand what lead me to
think about the following scenario: let's assume the worst case
scenario: those backups are public. Is it possible to securely protect
them using a human memorable password?
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