The Swiss Department of the Environment, Transport, Energy and Communications (UVEK) has started an investigation to determine the possibility of using software to tap VoIP phone calls.
A software prototype to do this has been developed by ERA IT solutions. It doesn't seem that the software would decypt any of the VoIP traffic itself. The software is a client side application that would listen to the computer's microphone and speakers to record the VoIP calls. The recordings made would be passed back in small packages over the Internet to the police authority. Two solutions to install the software on a suspect's machine have been presented. The first - police covertly install it locally. The second - the suspect's Internet service provider installs it remotely over Internet. How the later solution would be implemented is unknown to us.