Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Microsoft sends GitHub DMCA shutdown for Skype open source project

github.com

Post reply on HN
Print view View original

41–50 of 93 posts

Re: Microsoft sends GitHub DMCA shutdown for Skype open source project

#41

Post by Muromec »

ajross wrote: post #7
Xuzz wrote: post #5

Please note: this is not an attempt to clean-room reverse engineer Skype, or even to reverse engineer and create an open-source replacement. As shown with things like WINE, Microsoft does not (and probably cannot) take them down. No, that's not what "Skype Open Source" project is. This is a confusingly misnamed attempt to attach code to patched copies of copyrighted official Skype clients. Microsoft is not overreachi…

Are (were) they distributing the patched binaries or just the tools to do it?

There was deobfuscated version of skype 5.5 in downloads section of project. Not in repo.

Code in repo contains reimplementation of skype protocol (RC4 chiper, 41 and 42 encoders) and sample tool capable of sending IM to skype peer.

There also was some tools for extracting user certificate from skype profile.

Re: Microsoft sends GitHub DMCA shutdown for Skype open source project

#42

Post by skypeopensource »

nuclear_eclipse wrote: post #29
Iv wrote: post #26

Earlier quoted context omitted.

Yes, and reverse engineering to create specifications is done... how ? It requires examination of the only currently working implementation that we have.

From my understanding, you are allowed to decompile and inspect the released binaries, as well as intercept and analyze all inbound/outbound data, as long as you aren't modifying the running binary in any fashion. Things like debuggers are commonly used for this goal, as are tools like wireshark for analyzing the traffic. Once you create a specification based on your analysis, someone can create a clean-room implemen…

Exactly. Deobfuscated version just comfortable to debugging.

Re: Microsoft sends GitHub DMCA shutdown for Skype open source project

#43

Post by skypeopensource »

Muromec wrote: post #41
ajross wrote: post #7

Earlier quoted context omitted.

Are (were) they distributing the patched binaries or just the tools to do it?

There was deobfuscated version of skype 5.5 in downloads section of project. Not in repo. Code in repo contains reimplementation of skype protocol (RC4 chiper, 41 and 42 encoders) and sample tool capable of sending IM to skype peer. There also was some tools for extracting user certificate from skype profile.

Right. Now code moved to most fine named - https://github.com/skypeopensource/epycs

Re: Microsoft sends GitHub DMCA shutdown for Skype open source project

#44

Post by skypeopensource »

mseebach wrote: post #3

Better link: https://github.com/github/dmca/blob/db9b442f0ac68512d0ca83fe...

Read it please.

Demand for Immediate take-Down: Notice of Infringing Activity URL: https://github.com/downloads/skypeopensource/skypeopensource...

Its not to repo code. Its for patched binary, yes.

Re: Microsoft sends GitHub DMCA shutdown for Skype open source project

#46

Post by skypeopensource »

PuercoPop wrote: post #17

The authors website is http://skype-open-source.blogspot.com/ Apparently he had already been served with DCMA takedown requests. And talks about deofuscation. Doesn't sound like a cleanroom implementación.

Now, we are working on stage1, make working code and do specification. Takedown was because of patched binary which reversers used as black box for make specifications.

Re: Microsoft sends GitHub DMCA shutdown for Skype open source project

#47

Post by eli »

e1ven wrote: post #31
eli wrote: post #30

Earlier quoted context omitted.

Those links detail reverse engineering the binary. I think Iv's point is that reverse engineering an existing binary is not what "clean room" means.

If team A uses the binary to write a spec, and team B uses the spec to re-implement without direct help from team A, it's generally considered legit. This was the method used by Compaq to implement the IBM BIOS, back in the day.

Yup, I'm with you. I don't think anyone's done anything like that for Skype, though.

Re: Microsoft sends GitHub DMCA shutdown for Skype open source project

#48

Post by Iv »

e1ven wrote: post #31
eli wrote: post #30

Earlier quoted context omitted.

Those links detail reverse engineering the binary. I think Iv's point is that reverse engineering an existing binary is not what "clean room" means.

If team A uses the binary to write a spec, and team B uses the spec to re-implement without direct help from team A, it's generally considered legit. This was the method used by Compaq to implement the IBM BIOS, back in the day.

Yes, and we agree that team A's work needs to be done before team B can work. A's work is exactly what this DMCA notification tries to shut down.

Re: Microsoft sends GitHub DMCA shutdown for Skype open source project

#49

Post by Iv »

aGHz wrote: post #27
Iv wrote: post #26

Earlier quoted context omitted.

Yes, and reverse engineering to create specifications is done... how ? It requires examination of the only currently working implementation that we have.

The term "clean room" has a well established meaning you probably aren't aware of, I refer you to [1], it might clear up what the original reply was referring to. [1] http://en.wikipedia.org/wiki/Clean_room_design

I am well aware of the joke that is the clean-room process. Note that it supposes that the first team has access to the specification, source code, or any IP-encumbered indication about how the software in question works. In the case of Skype, the only public information we have is the binary.

Re: Microsoft sends GitHub DMCA shutdown for Skype open source project

#50

Post by cooldeal »

ktizo wrote: post #37
recoiledsnake wrote: post #34

Earlier quoted context omitted.

Maybe then you're not "supposed" to do it? For example, there is no reverse engineered libraries for Facetime and iOS API. If you use Apple's libraries, they can come after you for copyright infringement.

You can reverse engineer anything that you can reverse engineer. "Supposed" really doesn't come into it. If you buy a copy of osx and reverse engineer some libraries, then publish a description of their behaviour, so what?

That's fine, but if you publish the modified binaries of OS X's libraries with hacks to make them work in Linux along with the description, you will be in legal hot water.
Post reply on HN