Recently, 9th U.S. Circuit Court of Appeals ruled that authorities may seize laptops, cameras, smartphones or other digital devices at the US border without a warrant. This applies to anyone who enters the USA, including his citizens.
According to American Civil Liberties Union and National Association of Criminal Defense Lawyers, at least 6500 persons have had their electronic devices devices search since October 2008, under the “border search exception” law. The law, allow the border agents to aggressively search without a warrant the electronic devices of the international travelers at US border. The authorities are allowed to sent the devices seized miles away for expertise and copy all the data stored on them.
If in the beginning, the targets were whitehat hackers, Wikileaks associates or people who were suspected of having illegally download materials(from peer-to-peer networks), now the authorities can search anyone without any probable cause.
In response, wired.com release a basic guideline of how to protect your private data during the border search. They claim that the best way is to password-protect the devices and to add a second layer of security by encrypting all your data, in case the password gets bypassed. According to the law, you are allowed not to surrender the password, in case you are asked for it. Also, software like TrueCrypt and FreeOTFE can hide the encrypted partitions, offering plausible deniabililty if forced to reveal the encryption keys.