7 ms·

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 thing

• ajross 14y ago
  Are (were) they distributing the patched binaries or just the tools to do it?
  • cube13 14y ago
    It's hard to tell. The author is clearly not too fluent with English, so it's difficult to tell exactly what he's saying. It sounds like it's based on a decompiled and recompiled version of the core Skype kernel dlls and not a clean room implementation.
  • Muromec 14y ago
    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.
    • skypeopensource 14y ago
      Right. Now code moved to most fine named - https://github.com/skypeopensource/epycs https://github.com/skypeopensource/epycs
• Iv 14y ago
  How exactly is one supposed to make a clean-room reverse engineering in the absence of any documentation and sophisticated obfuscation on Skype's part ?
  • wmf 14y ago
    It's hard, but people have made progress with that approach: http://recon.cx/en/f/vskype-part1.pdf http://recon.cx/en/f/vskype-part1.pdf http://recon.cx/en/f/vskype-part2.pdf http://recon.cx/en/f/vskype-part2.pdf
    • eli 14y ago
      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.
      • e1ven 14y ago
        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.
        • eli 14y ago
          Yup, I'm with you. I don't think anyone's done anything like that for Skype, though.
        • Iv 14y ago
          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.
          • recoiledsnake 14y ago
            > A's work is exactly what this DMCA notification tries to shut down. What part of A's work involves distributing deobfuscated binaries to the general public? Team B should only have access to the specifications developed by Team A and nothing else from them. That's the whole point of isolating them.
• skypeopensource 14y ago
  You are wrong. You eyes are blind by hating. Stop. Listen the Nature. Skype-open-source code here: https://github.com/skypeopensource/epycs https://github.com/skypeopensource/epycs repo was closed because i host in download section deobfuscated skype5.5 binary, my fault.
  • daeken 14y ago
    No, that's bullshit. https://github.com/skypeopensource/epycs/blob/master/sources/skypkt/decode41.c#L405 https://github.com/skypeopensource/epycs/blob/master/sources... That function right there (and the vast majority of the rest of the file) is a straight decompiled version from Skype. You even use the register names and comment with addresses from the binary. Having spent a lot of time reversing apps myself, this is a straight copyright violation. Your code is a directly derivative work from Skype.
    • caf 14y ago
      I wonder if that's a small enough component to count as de minimus copying.
      • gtirloni 14y ago
        Is there the notion of minimum copyright infringement?
        • fffggg 14y ago
          Yes and no. There is no such notion in copyright law. Case law is unclear, however: http://en.wikipedia.org/wiki/De_minimis#Copyright http://en.wikipedia.org/wiki/De_minimis#Copyright
          • caf 14y ago
            The jury instructions issued by the judge in the ongoing Oracle vs Google case make considerable reference to the principle: http://www.groklaw.net/pdf3/OraGoogle-1018.pdf http://www.groklaw.net/pdf3/OraGoogle-1018.pdf