>That's a long introductory way of saying: KBFS on phones will be fantastic - but I've long intended to move my (pretty much personal use only, but still) app to using a database rather than raw files, so is there any plan for programmatic access to KBFS for other apps? I realise there are non-trivial issues concerning permissions there, but it could be really great - perhaps silo other apps from full access, e.g. 'App is requesting access to KBFS/Appname, approve?' and 'App is requesting access to KBFS/none-of-its-business, approve?'?

Alternatively, have you considered implementing an input method provider as the means of inputting passwords into your apps? I know that on Android you can create your own input method apps. I think on iOS you will need to jailbreak the device and even then I don't know if you can make your own input method app for it.

I am imagining that the input method shows you your list of credentials and allows you to select from it.