This is very different to what the article is talking about, since it encrypts your passwords, but the article talks about hashing which is one-way.
[1] http://help.agilebits.com/1Password3/agile_keychain_design.h...
When is this not the case?
I would love to see research about the use of keys and passphrases. Especially, do people who have a key then chose a weaker master password?
I tried it against mine, and was significantly disappointed in how quickly even my laptop could attack it. I promptly increased the complexity of my master password.
Possibly worse, 1Password used to have a mistake in their key generation algorithm that means you could verify a password without the time-consuming key stretching, effectively making it thousands of times faster to crack. JTR doesn't use that method though.