While I also like that comic, this doesn’t exactly happen regularly and no one here ever needs to worry about something like this.
So unless you’re an international spy or some very important whistleblower that won’t happen.
A court could probably order you to decrypt it but again if they have to do that, odds are that you are doing something pretty terrible.
These SD cards are for photographers and normal expandable storage for devices and not state secrets or something highly illegal.
Honestly, neither does having to securely wipe SD card (or any storage device for that matter) as one cross the international border like the thread further up suggests. So the whole thing is just having fun with (potentially roleplaying) over paranoid people :)
Tbh, if you’re that nervous about crossing the border with data, I’m sure you could find other ways to use the internet and decent encryption (behind multiple layers and/or people with a Deadman’s switch if you’re really paranoia and worried a judge will force you to unlock the precious 4mb worth of information) to protect your data when crossing a border.
Or probably even safer if you’re talking about just 4mb of data: send it from a random address in one country to a postbox in your destination or something by post. Tampering with mail carries a pretty heavy fine in most countries, chances a random postman opens a random envelope to a random address abroad are basically non existant. Security through obscurity.
I like reading about infosec, but some of it borders on absolute paranoia tbh :)