Outlaws are increasingly using the internet telephone service Skype to prevent their conversations being monitored, Swiss law enforcement officials report. Investigators are currently pursuing dozens of drug-related cases where Skype has been used for communications purposes. But the firm is keeping quiet over the issue.
Skype software lets computer users talk to each other for free and make cheap calls to mobiles and landlines. But unlike other voice-over-internet services, its calls are heavily encrypted using complex mathematical operations that make them very hard to snoop on.
“Criminals know that the police have difficulties monitoring Skype,” said Christoph Winkler, a Zurich prosecutor in charge of drug-related and organised crime in the canton. The fact that drug dealers use Skype is no accident, he added, as the police frequently have to resort to wiretapping in such cases.
Skype communications zip around the internet encrypted with “keys” – essentially very long numbers. These numbers are 256 bits long – twice as long as the 128-bit keys used to send credit card numbers over the internet. In theory Skype’s keys would take much longer to crack than 128-bit keys, which are themselves regarded as practically impossible to break.