Border control officers at land crossings and airports in many countries have the right to search traveller’s laptop and smartphones without a court order, that is where your family photos, banking details and list of visited websites reside. Lawyers, doctors and businessmen should also be concerned about this practise, if you care about your privacy here are some tips to protect your digital data from noisy border agents:
Backup your data: There is the possibility that a border agent damages or seizes your device, always have a backup somewhere else and never take the backups with you, leave them at home. If you need to backup your data at the guess country, i.e. holidays photos, use an encrypted cloud service like SpiderOak or Tresorit, encrypt the and SFTP to your server, or back it up to an encrypted USB thumbdrive and mail it to your home.
Use whole disk encryption: Whenever it is possible use full disk encryption as opposed to file encryption, there are too many places where the operating system creates temporary copies of personal data to be able to securely wipe everything. If you can get away with using a Linux live CD for your day to day Internet usage this is the best course of action, remove the laptop hard drive or wipe it, with a live CD nothing will be saved to your hard drive.
The country you visit could have different encryption laws to that of your home country, in the UK for example, it is a criminal offense not to reveal the password to your encrypted files when law enforcement asks for it, the penalty for refusing is up to 5 years in prison. If unsure about local cryptography laws, store your data encrypted on the cloud and take only a live CD with you, download your files only after going through customs and make sure to never save anything as you could be asked for access at any time during your stay or on your way out.
If you are using an SD card for storage, extract it and wipe the memory card on a PC using specialist software (Eraser, ProtectStar, BCWipe, etc). On Android phones, download the Whispercore app for full phone encryption. Another choice is to use a second phone only for travelling, unless you really need a smartphone abroad, buy a cheap phone and transfer your SIM card there, this should also help you protect against theft by making it less attractive.
Border agents might want to look at your holiday photographs for whatever reason, sometimes searching for illegal pornography or to corroborate that you really have been on a leisure break. There is no easy protection against this other than extracting the memory card, encrypting it and mailing it to yourself, it will help not to look suspicious by coming back from holidays with an empty camera by introducing a second memory card in the digital camera with photos you don’t care about anyone seeing
The decision on whether to search your electronic devices or not will take into account the countries you have visited, your background (criminal record), how you behave at the border, and the state of alert at the time, electronic devices can also be searched at random or just because the border officer feels like it.
Border control agents could swap test your laptop for bomb residue, this test is called Explosive Trace Detection and it can be carried out on any piece of checked baggage.
For further information read the Electronic Frontiers Foundation Guide for Travelers Carrying Digital Devices