Open Source Researcher Reverse Engineers Skype

A Russian researcher is claiming to have reverse-engineered the source code for voice-over-IP service Skype, and is offering the binaries for download on a new blog set up for the purpose.

“While ‘Wall Street Journal’ makes politics and skype today’s trend, i want to publish my research on this,” wrote freelance researcher Efim Bushmanov on the blog. “My aim is to make skype open source. And find friends who can spend many hours for completely reverse it.”

Bushmanov acknowledged that there are several limitations to the posted code. For example, that it was created using version 1.4 of Skype, which has now slightly changed. It will also not work on any 5.x versions of Skype, nor will it work for 3.x or 4.x versions without a new ‘login’ certificate.

Despite this, the binaries have already been downloaded thousands of times because, as Bushmanov points out, it gives developers a “unique chance to take a look on skype internal protocol and encryption”.

Unauthorised usage

Skype has responded to the news, condemning any attempt by third parties to crack its protocol.

“This unauthorized use of our application for malicious activities like spamming/phishing infringes on Skype’s intellectual property,” the company said in a statement. “We are taking all necessary steps to prevent/defeat nefarious attempts to subvert Skype’s experience. Skype takes its users’ safety and security seriously and we work tirelessly to ensure each individual has the best possible experience.”

Skype’s protocol is proprietary, and is therefore likely to be a key element in Microsoft’s recently announced $8.5 billion (£5bn) acquisition of the company. It is unlikely that Microsoft allow the blog stay live for long.

The deal, which values Skype at around $13 for each of its 600 million registered users, is expected to enable Microsoft to increase its support for web calling in its Lync communications server, and its Windows Phone mobile OS, as well as compete better against Google and Facebook in social networking.

However, some commentators have suggested that Microsoft overpaid for Skype, and that the acquisition could end up being a very expensive mistake.

Last week, the VoIP service suffered some major down-time, with users around the world unable to sign on and make calls from around 12:15pm UK time on 26 May. The crash prompted a storm of updates on Twitter, with many users directing their anger at Skype’s new owner Microsoft.