Article on ComputerWorld about a case where the FBI used a technology to track computer keystrokes of a suspect in order to get his password for PGP encrypted files on his computer. They apparently could not crack the encryption on the files.,00.html

Quote from the acrticle:
"The government is making the case that they can install sophisticated technology on computers and make a national security claim" to keep it secret, he said. If it became a routinely accepted argument for preventing its disclosure to defendants in court, "it would radically alter our concept of due process and the rights of criminal defendants."