"Wiping is obviously extremely suspicious and asking for trouble"

It's sad this is the default view. It's his device, his data, his life on that phone. If he had wiped the phone before the interrogation it wouldn't be a problem. How long before? A second before? A week before? But wiping the data a minute later is suddenly asking for trouble.

We noted in the border search guide that lying to the agents in response to their questions is potentially a crime in its own right (even if it's not done in order to hide anything illegal). We thought that this made hidden volumes quite tricky, particularly if one's intent was to pretend to comply with a question or request while actually not complying.

Problem is „are you sure you marked for deletion all the correct things” because you could have already deleted it before traveling or moved to other device you don’t travel with.

Selection on border control might be arbitrary, they can hold you or send you back over a photo or something you wouldn’t think should be a problem.

Ideally you would like to have all wiped just in case but then you really stand out…

That's a more risky strategy. What if you added new files since the last time you updated the deletion profile? It's also technically more challenging. You have to think about what might be in RAM, caches, backups, etc.

The good thing about a total wipe is that it's very easy to implement, and it's hard for it to go wrong. You just encrypt the whole drive and, when you want to wipe it, erase the key.

Deleted stuff can easily be recovered. I think the full clean will remove the encryption keys hence making it unrecoverable.

Yes, this also has the advantage of speed perhaps. I can see, deleting specific apps (and their data) as thing #1, and thing #2 would be certain directories. Of course, the problem is, are icons going to be vanishing off the home screen, when the agent is looking at it? Or will the unlock -> screen coming on, be super slow?

Of course the problem there is, many people have an app store installed, and app stores have histories. And logs. And "what you used to have installed" is so easily found under Google Play, for example.

As someone else said in this thread, the law isn't code. It's not if-then statement based. It's also predicated upon intent in many cases. What actions did a person take, and why, when told to (for example) unlock their phone.

The problem here is that if you are asked to unlock your phone, any action you take to thwart that request by "trickery" to get data deleted, could be construed as 'deleting evidence'. So while some methods might make it more difficult for the border agent to realise "something happened", if they're suspicious still, then you're still in hot water.

In the eyes of the law, the court, and likely the jury, you've done a sneaky thing to thwart evidence collection.

The only safe method is a full wipe prior to travel. In this manner, you're not deleting evidence when told to hand it over. It's an entirely different bar. They can be cruel about it, and take your phone for a few months, but you're not going to be in legal hot water.

In as no one will see the phone is wiped until you are compelled to unlock it, there's no greater change of the phone being seized. You're already being investigated. Just be blunt, say "Whenever I travel, I just wipe it", and that's that.

This is why it's a shame that GrapheneOS has no viable backup solution. Its build in method is unreliable, and doesn't work very well, and is gitchy, it's a very well known problem.

And Android and ADB sometimes have issues with large backups of directories, and so you have to manage that with tar + stream and other business, but at least working around that is easy.

But if you could backup individual apps and all their data, you could uninstall all your privacy laden stuff, cross the border, and reinstall in minutes.

That's the true, legal way to travel safely. Especially if the app removal resulted in a 'shred' of the data files instead of delete.

If anyone has ever struggled with large data backup/restore, here's the only real method I've found for copying large swaths of files from/to via adb:

  adb exec-out 'tar --dereference --create /storage/emulated/0/dir/  2>/sdcard/backup-errors.txt' |dd of=/tmp/backup-$(date +%Y%m%d).tar && adb shell cat /sdcard/backup-errors.txt

  dd if=backup-20250309.tar | \
  adb exec-in 'cd /storage/emulated/0/tempdir; tar xpvf -  2>/sdcard/restore-errors.txt' && \
  adb shell cat /sdcard/restore-errors.txt