Criminals are increasingly to a familiar service in order to avoid police wiretapping: Skype. "Criminals know that the police have difficulties monitoring Skype," said Christoph Winkler, a Swiss prosecutor. Skype, and similar VoIP programs, are currently fall outside of US and European wiretapping jurisdiction. Police can’t legally listen in. Unlike telephone companies, Internet telephony companies are not required to cooperate with the police. Another barrier is Skype’s 256-bit Rijndael encryption -- twice as thick as that used for processing credit cards -- which is much more difficult to crack than regular phone calls. So difficult, in fact, that the National Security Association is offering hackers a large reward if they can break it.

Skype will not share its encryption data with authorities.

In June of last year, Jennifer Caukin, Skype's director of corporate communications, told CNET: "We have not received any subpoenas or court orders asking us to perform a live interception or wiretap of Skype-to-Skype communications. In any event, because of Skype's peer-to-peer architecture and encryption techniques, Skype would not be able to comply with such a request."

The European Union’s Eurojust agency, which coordinates judicial investigations across member countries, is investigating “the technical and judicial obstacles to the interception of Internet telephony systems.”

The latest country to warn of Skype’s potential aid to criminals was in Italy, where police wiretappers overheard a Milan cocaine trafficker tell one of his associates to switch to Skype to discuss a sale.

Last year, German police hired a company to create Trojans to capture Skype voice and video.

By Mark Alvarez