Wiretapping and Cryptography Today:
The 2010 U.S. Wiretap Report was released a couple of weeks ago, the latest in a series of puzzles published annually, on and off, by congressional mandate since the Nixon administration. The report, as its name implies, summarizes legal wiretapping by federal and state law enforcement agencies. The reports are puzzles because they are notoriously incomplete; the data relies on spotty reporting, and information on "national security" (FISA) taps is excluded altogether. Still, it's the most complete public picture of wiretapping as practiced in the US that we have, and as such, is of likely interest to many readers here.
We now know that there were at least 3194 criminal wiretaps last year (1207 of these were by federal law enforcement and 1987 were done by state and local agencies). The previous year there were only 2376 reported, but it isn't clear how much of this increase was due to improved data collection in 2010. Again, this is only "Title III" content wiretaps for criminal investigations (mostly drug cases); it doesn't include "pen registers" that record call details without audio or taps for counterintelligence and counterterrorism investigations, which presumably have accounted for an increasing proportion of intercepts since 2001. And there's apparently still a fair bit of underreporting in the statistics. So we don't really know how much wiretapping the government actually does in total or what the trends really look like. There's a lot of noise among the signals here.
But for all the noise, one interesting fact stands out rather clearly. Despite dire predictions to the contrary, the open availability of cryptography has done little to hinder law enforcement's ability to conduct investigations.
Since 2002, the annual wiretap report has included a curious statistic: the number of times law enforcement encountered encryption on an authorized tap, along with the number of times that this prevented them from getting the evidence they were seeking.
So how did encryption fare versus wiretapping? Not well!
the latest wiretap report identifies a total of just six (out of 3194) cases in which encryption was encountered, and that prevented recovery of evidence a grand total of ... (drumroll) ... zero times. Not once. Previous wiretap reports have indicated similarly minuscule numbers.