Comment So I looked at that code (Score 1) 231
Apparently not a lot of people bothered, although many were quick to repost the story under headlines like “Skype protocol reverse-engineered, source code published”. tl;dr: An important step on a long way is made, but it's going to take years until an alternative Skype client becomes reality.
Bushmanov based his work on de-obfuscated binaries of old versions of Skype for Windows which some other hackers had produced before (the first archive). He used IDA Pro to analyze the code (the second archive contains IDA databases) and gain understanding of some aspects of the protocol, which has layers of encryption and obfuscation. He also patched the binaries to add some logging. Basing on his findings, we wrote a program that can connect to a given [super]node and send an instant message for a given user. The third published archive contains a bunch of MS Visual Studio projects representing his progressive advancement.
To actually connect and send a message, the program needs so-called credentials. It seems to be a sort of session key issued by Skype login servers for 30 days or every time the user enters the password. Sean O'Neil wrote a hack in July 2009 that could connect to a login server and register a new user or log in as an existing one, procuring credentials. Since 2009 this has stopped working, probably because of changes on the server side. So instead Bushmanov used a hack to obtain credentials from running Skype for Windows.
To summarize: Bushmanov built upon prior work in the field and made an important step. There are hundreds of steps like that to be made until an alternative Skype client is possible. Microsoft has plenty of time to react, whatever strategy they choose.
One more thing: when Skype says they're going to do their best to defeat reverse-engineering attempts because the results can be used by spammers, they're lying. It's already possible to use Skype for spamming by automating it. What they're going to fight for is their business model, which relies upon there not being any alternative clients.
