It's well known that organizations with nefarious and often criminal goals support and distribute malware and spyware that allows them to snoop on and/or manipulate people's computers. However, what is less well-known is that some of the people behind spyware are ostensibly the "good guys"—law enforcement officers who install the software on suspects' computers to assist them with their investigations. The existence of "policeware" is not well-known, but the US government has used this sort of software before. In 2001, federal agents obtained permission from a judge to enter a suspect's home and install keylogging software on his computer. The...