The complete description of the feature on the Lantern site is "Pass code bypass with certificate file from syncing computer" so I don't think "until the device is unlocked" is the accurate way to phrase it. It seems that Lantern re-uses the pre-existing credentials set up between the computer and the phone.

The complete description of the feature on the Lantern site is "Pass code bypass with certificate file from syncing computer" so I don't think "until the device is unlocked" is the accurate way to phrase it. It seems that Lantern re-uses the pre-existing credentials set up between the computer and the phone.

edit: And in re-reading your question it seems you may be aware of this. A quick perusal of the iOS developer documentation doesn't yield anything to me but you can likely determine this for yourself if you have a mac you sync your phone to.

from a terminal window run the command sudo fs_usage -wf filesys | grep -i itunes and you should be able to see what files iTunes consults when you connect your passcode-locked phone.