This is the type of thing that a law enforcement agency needs to know.

CNN: Police identify Twitter user accused of making threat

At the time, the federal government was also pushing hard to get companies to add so-called "key escrow" type technologies to their encryption products so that law enforcement could obtain access to encrypted data on demand.

CNN: Technology - Security flaw discovered in Network Associates PGP software

"Other than some type of key-recoverable system, there is currently no viable technical solution to this problem for law enforcement, " he said.

BBC: Security and law enforcement: the government view