Cryptography, Blank Minds and the Law

An Eccentric Anomaly: Ed Davies's Blog

This afternoon I had a little crypto-fright, forgetting an important passphrase for a while.

This morning I went to Lybster and my site to take delivery of a scaffold tower. Apart from opening up the boxes to make sure they looked basically OK the only other thing I did was swap over the USB hard disks I use for backup - I keep one in my container to be offsite from where my laptop lives. Doing anything else would have been very unpleasant and dangerous because of high winds and hail showers.

Getting home I did a fresh backup onto the new disk. I also had a quick play with the copy of Ubuntu installed on that disk to make sure there was nothing relevant on it as I'm thinking of replacing it with Qubes OS to have a play with that on something a bit faster than the USB memory stick I've tried it from previously (which wasn't too terribly slow, actually, apart from starting up virtual machines).

Having messed around with these other partitions with their own passwords and keys I then booted back into my laptop's normal Ubuntu system and suddenly my mind went blank: I couldn't think what the passphrase for the full-disk encryption was.

I'd just taken a backup and could remember the passphrase for the backup so it wasn't completely catastrophic. Still, it'd have been a big nuisance to have to reinstall everything and get it all set up the way I like it.

What's really strange is that this is a passphrase I've typed pretty-much every morning for many months. Probably it'd become so automatic that when I thought about it in the context of other passphrases I got confused - like trying to describe how to tie your shoes laces.

It came back to me a little while later, after I'd gone off and read something irrelevant. Still, I can imagine that under the stress of the situation it would be easy for somebody served a RIPA Section 49 notice to similarly fail to remember a passphrase out of context and for this to be a longer-term effect.