Revocation certificates [was: time delay unlock private key.]

[Leo Gaspard]

On Thu, Jan 23, 2014 at 03:08:40PM -0800, Robert J. Hansen wrote:
> >Yet, I agree I would not send my encrypted private key. But having your
> >divorced
> >spouse bruteforce 90 bit of passphrase just to annoy you... seems quite an
> >unreasonable threat to me.
> 
> It is.  That's why that's not the threat being defended against.
> 
> The threat is against your spouse seeing you enter your passphrase.  It's
> very easy for roommates to discover each other's passwords and passphrases;
> sometimes it happens by accident.  Everyone knows not to enter a passphrase
> with a shoulder surfer around, but if you and your spouse are sitting on the
> couch with your laptops open and you receive an encrypted email, are you
> really going to tell her, "Sorry, honey, I have to take this into the other
> room so I can enter my passphrase without worrying about you spotting it"?
> 
> So long as there's marital bliss, you're perfectly safe.  You just can't
> rely on that lasting forever.

Well... I don't know how you type, but someone looking at me who sees me type my
passphrase would really have to try hard to guess what passphrase I am using.
And even more to remember a seven-word sentence seen once.

BTW, I once had a fun experiment: just type an eight random chars password with
no protection at all, and asking people behind me to remember it. The password
was displayed as I typed it, and left approx. two seconds more. No one managed
to see it and remember it. A few days later, I conducted the same experiment
with the same people and the same password, and no password was successfully
guessed. Sure, the information gathered would be enough to bootstrap a
successful "bruteforce", but the experiment was a lot more easy to complete than
peeping at and remembering a seven-word password.

So, if the spouse is doing it, then marital bliss has already come to an end,
and one should have noticed it.

Yet, being unmarried, I cannot say anything about such things.

So, within that threat model, revocation certificates are useful for sure.
Assuming one's spouse would first grab the secret key and remember the
passphrase before divorce.

Thanks for making that point!

Leo