Carry On: Sound Advice from Schneier on Security

Chapter 7

Travel and Security

Crossing Borders with Laptops and PDAs

Originally published in the Guardian, May 15, 2008

last month a US court ruled that border agents can search your laptop, or any other electronic device, when you're entering the country. They can take your computer and download its entire contents, or keep it for several days. Customs and Border Patrol has not published any rules regarding this practice, and I and others have written a letter to Congress urging it to investigate and regulate this practice.

But the US is not alone. British customs agents search laptops for pornography. And there are reports on the Internet of this sort of thing happening at other borders, too. You might not like it, but it's a fact. So how do you protect yourself?

Encrypting your entire hard drive, something you should certainly do for security in case your computer is lost or stolen, won't work here. The border agent is likely to start this whole process with a “please type in your password.” Of course you can refuse, but the agent can search you further, detain you longer, refuse you entry into the country and otherwise ruin your day.

You're going to have to hide your data. Set a portion of your hard drive to be encrypted with a different key—even if you also encrypt your entire hard drive—and keep your sensitive data there. Lots of programs allow you to do this. I use PGPDisk (from pgp.com). TrueCrypt (truecrypt.org) is also good, and free.

While customs agents might poke around ...