Microsoft patent points to Skype snooping

Just what the government ordered

A new Microsoft patent points towards Skype becoming equipped for lawful interception, which could be important as the service grows up to challenge traditional telcos.

The patent was filed back in 2009, but published* last week and picked up by Computerworld. Titled "Legal Intercept", it covers one way in which a VoIP-based communications system might enable a call to be intercepted and covertly recorded, naming Skype as one of the services to which it could be applied.

Microsoft bought Skype back in May, but only received approval for the deal in June – so hasn't had much time to do anything with the VoIP leader. Skype is hugely successful, with 170 million registered users, but it's been very secretive about its protocols and security, refusing interoperability and asking users to just trust in Skype for their security.

That won't wash in the real world, and neither will denying governments the right to listen in on their citizens. Most of us accept that security forces need to occasionally tap into phone lines, hopefully with suitable judicial oversight, but Skype's apparent reluctance to permit such taps has resulted in rumours of secret deals and government-backed attacks on the cryptography used to protect Skype calls.

The patent describes how client, or network, software can be surreptitiously alerted that incoming and/or outgoing calls are to be monitored for a specific user. Such calls are then copied (packet by packet) to the monitoring server without the user being aware. The patent suggests the interception software could be placed in a NAT or router, but also incorporated into the VoIP client itself.

India has made it clear that Skype risks being kicked out of the country unless it sorts out some sort of lawful intercept capability, and other countries will be quick to follow India's lead. So if Microsoft wants to see Skype spreading around the world then it will need to have just what's described in the Legal Intercept patent.

Citizens aghast that their VoIP calls could be intercepted might be annoyed, but they'd be better off petitioning their governments, rather than raging against the companies trying to obey the law. ®

* That's "published", not "granted" as we earlier stated - our mistake.