[Cryptography] Keeping backups (was Re: Separating concerns

[zooko]

On Thu, Aug 29, 2013 at 01:30:35PM -0400, Perry E. Metzger wrote:
> 
> So, as has been discussed, I envision people having small cheap
> machines at home that act as their "cloud", and the system prompting
> them to pick a friend to share encrypted backups with.

The Least-Authority Filesystem is designed for this use case (among a small
number of other use cases).

> Inevitably this means that said backups are going to either be
> protected by a fairly weak password or that the user is going to have
> to print the key out and put it in their desk drawer and risk having
> it lost or stolen or destroyed in a fire.

In LAFS, the keys are strong, computer-generated keys, so you have to print
them out or write them down. Printing them in triplicate and storing them in
separate locations seems like a good trade-off of the risk of theft vs. the
risk of loss, for the reasons you give:

> I think I can live with either problem. Right now, most people
> have very little protection at all. I think making the perfect the
> enemy of the good is a mistake. If doing bad things to me requires
> breaking in to my individual home, that's fine. If it is merely much
> less likely that I lose my data rather than certain that I have no
> backup at all, that's fine.
> 
> BTW, automation *does* do a good job of making such things invisible.
> I haven't lost any real data since I started using Time Machine from
> Apple, and I have non-technical friends who use it and are totally
> happy with the results. I wish there was an automated thing in Time
> Machine to let me trade backups with an offsite friend as well.

The Least-Authority Filesystem comes with a nice backup tool ("tahoe backup"),
but it does not come with a nice GUI for your non-technical friends.

Regards,

Zooko