Well before the FBI's recent demand that Apple give up the keys to the encryption used in an iPhone 5c, the bureau engaged in a similar effort, according to a story in Wednesday's New York Times.

Early in 2003, the FBI received permission from a judge to install surveillance software – now referred to as spyware or malware – on the computers of a group that it hoped would allow them to read encrypted emails.

The investigation, dubbed Operation Trail Mix, involved an animal rights group suspected of "eco-terrorism" against a lab that used pharmaceutical testing on animals.

While it appears that the FBI was unable to break the encryption, it was able to work around the problem – likely using a form of keylogging – though its methods remain classified. An FBI wiretap was disclosed at the suspect's trial, but the software hacking was not, as prescribed by law.