Tuesday, 18 July 2006

Chinese Clone Reverse Engineers Skype Protocol

The USD 2.6 billion dollar question Skype watchers often ask themselves has now been answered. Charlie Paglee, cofounder of Voice over IP startup Vozin Communications, is reporting on his blog that a company in China has successfully reverse engineered the Skype protocol. "Today I received a call through Skype from a friend at a company in China, except he told me he was not using Skype to call me. His company has successfully reverse engineered the Skype protocol and he wanted to call me in the United States to see how it worked between physically distant IP addresses. We talked for a little over nine minutes before the call dropped. Then I called him back using my Skype and we spoke for another three minutes." Paglee said he participated in two Internet calls from the China-based unit, using the cloned version. The first call, he said, had a noticeable echo, but the second was clear.

Right now, Paglee writes, every computer with Skype installed on it can be used as a relay to carry data between two other computers when both of those computers are only allowed to make outgoing TCP calls. This means that very soon Skype users will have an alternative client which will not hijack their computer. This could eventually have a very negative effect on the Skype network if too many people choose not to act as Skype Super Nodes and the network starts to deteriorate.

Skype has issued a statement that there is no evidence of such reverse-engineering and that, even if true, such a clone would not have the feature set and reliability of Skype.