UNTIL now voice-over internet services have been difficult for police to tap. The technology is latest to offer governments a way to intercept web chats

New eavesdropping technology could allow government agencies to ´silently record´ conversations on internet chat services like Skype in real time.

Until now, so called voice over internet protocol (VoIP) services have been difficult for police to tap into, because of the way they send information over the web.

The services convert analogue audio signals into digital data packets, which are then sent in a way that is costly and complex for third parties to intercept.

That has led some countries to block VoIP services on security grounds and led the FBI to push for powers to force internet chat providers to build in ´backdoors´ that its agents can use to wiretap suspects´ conversations.

But now a California businessman has obtained a patent for a ´legal intercept´ technology he says ´would allow governments to "silently record" VoIP communications´.

Dennis Chang, president of VoIP-PAL, an chat service similar to Skype, claims his system would allow authorities to identify and monitor suspects merely by accessing their username and subscriber data, Slate reports.

According to the patent, they could also be tracked down by billing records that associate names and addresses with usernames.

Such a capability would make not only audio conversations but ´any other data streams such as pure data and/or video or multimedia data´ open for interception.

Internet users who are paranoid enough to use false subscriber data and services to mask their IP addresses could be able to circumvent the identification.

But Mr Chang´s patent would nevertheless restructure the way VoIP data is sent over the internet to make it much easier for authorities to track calls.

VoIP services work by digitising callers´ analogue voice signals and transmitting them as packets of digital data to send over the internet directly to recipients.