The US Bill of Rights is on the side of a man suspected of having child pornography on his laptop computer – because his hard drive is encrypted and only he knows the password, the Fifth Amendment protects him from incriminating himself by disclosing it.  

Sebastian Boucher, a Canadian citizen with a US residency permit, was stopped while crossing the border and agents say thay found files containing child pornography on his laptop.
Boucher was arrested, although he claims that the child pornography was downloaded in error and he intended to delete it.
When federal agents tried to access the files later on, they couldn't as encryption software from PGP prevented them from seeing the contents of the hard drive.
A now a magistrate has ruled that Boucher cannot be forced to disclose the password.
The US government has appealed the ruling.