8 ms·

I don't understand this project. According to the creator, the purpose is "to make Skype open source" [1], but the project relies on binary files distributed by

by martey 15y ago

I don't understand this project. According to the creator, the purpose is "to make Skype open source" [1], but the project relies on binary files distributed by Skype. As a result, they have repeatedly faced DMCA notices [2] which regularly causes the source code is become unavailable. An earlier blog post made it to Hacker News. I found the comment at http://news.ycombinator.com/item?id=2611728 http://news.ycombinator.com/item?id=2611728 insightful. [1]: http://skype-open-source.blogspot.com/2011/06/skype-protocol-reverse-engineered.html http://skype-open-source.blogspot.com/2011/06/skype-protocol... [2]: https://github.com/skypeopensource/skypeopensource/issues/1 https://github.com/skypeopensource/skypeopensource/issues/1

beza1e1 15y ago
For a clean room reverse engineering they could analyse the Skype binaries to document the protocol.
- kogir 15y ago
  Clean room requires that those creating the implementation don't have access to the original implementation. Having the same person(s) inspect the binaries and create an implementation fails this requirement. See: http://en.wikipedia.org/wiki/Clean_room_design http://en.wikipedia.org/wiki/Clean_room_design
  - skypeopensource 15y ago
    But how can you test if you protocol/document correct? Yes, Epycs code may have question about legit and some other stuff. But after it going to a beta or stable stage. We can use Epycs protocol documentation to write, for example, epycs.java and make it fully "clean room".
    - cwzwarich 15y ago
      You get someone who is not involved with the reverse engineering to test it.
    - dredmorbius 15y ago
      Look up the term "Chinese Wall". What's required (for purposes of courtroom defense) is a clearly documented procedure in which those who have access to the source being reimplemented (the spec writers and testers) NOT be the coders, and vice versa. Another example is the SMB/CIFS reimplementation in the case of Samba. Here, because the protocol was an over-the-wire system, analyzing network packets (not covered by source analysis proscriptions) was sufficient to create a Free Software implementation.
      - deleted 15y ago
        [deleted]
      - skypeopensource 15y ago
        Yeah, we will do it. But now project still at first stage.
- rplnt 15y ago
  Can't be the protocol itself patented?
  - nikcub 15y ago
    that would involve describing it
    - pornel 15y ago
      Describing just one part of it could be sufficient to sue, but not sufficient to develop a client. Software patents are intentionally vague, so I doubt anybody could write a working client based on a patent alone (even if whole protocol was claimed to be described).
      - caf 15y ago
        You are probably correct, but this is an abuse of the patent system, since the quid pro quo for patent protection is the disclosure of the invention to advance the state of the art.
Deinumite 15y ago
Yeah... I don't really understand what their issue is to be honest. It really is up to Skype if they want to release their protocol. You can't really force anyone into being open source. I actually disagree with their methods, its the same as a closed source company violating the GPL when they steal source code like this.
- dchest 15y ago
  It really is up to Skype if they want to release their protocol. This isn't true. Nothing stops you from analyzing and implementing their protocol. This project, however, is only the first part.
- nikcub 15y ago
  Reverse engineering has given us so many good things - Samba, OpenOffice, Wine, MAME (and other emulators) the bitkeeper debacle, which gave us git. Then there are all the Linux and UNIX drivers that were written by reverse engineering windows drivers because vendors weren't supporting those operating systems. The guys who reverse engineered Exchange Server were acquired by Cisco. I don't understand why the Skype case is 'evil'. distributing the binaries may violate terms of service, but it isn't illegal in large parts of the world.
  - excuse-me 15y ago
    It did also give us the PC running Windows - so there is a dark side ;-) Unless your home PC is an IBM PC-AT it's the result of reverse engineering.
tibbon 15y ago
Remember, open source doesn't mean free. It just means you can view the source.
- _delirium 15y ago
  That's not the usual use of the term in tech. Even Microsoft, after some initial confusion, has settled on using "shared source" rather than "open source" to describe situations where they share the source but not under an open-source-definition-compatible license.
- simonw 15y ago
  The Open Source Definition provides a very clear explanation of when the term open source should be used: http://www.opensource.org/osd.html http://www.opensource.org/osd.html
  - bigiain 15y ago
    In one sense, I feel "The Open Source Movement" have co-opted a plain english two word phrase. Their introduction there can be rewritten as "Open source doesn't just mean the source is open. We claim there are also implications about the means of distribution." It's as though someone was telling people "free beer" doesn't just mean beer that's free, it also needs to be in glass not cans - free beer in cans needs to be called something else… I think there's a lot of "open source" software out there that is not "open source(tm)". I'm not sure "the open source movement" are doing themselves any favors by aggressively defending their particular definition of a descriptive phrase that is widely known and easy to assume you understand. (But I also understand the need for specific technical meanings in the software field, and that phrases like "open source" end up being part of the field's jargon, and have far more specific technical meanings than the "plain english" deconstruction of the words indicate. I just think the "open source" case has backed itself into a corner where people assume a plain english interpretation of the phrase, then have the "open source movement" people need to jump on them and say "no, you're wrong". As displayed upthread.)
    - djeikyb 15y ago
dr_rezzy 15y ago
For spamming this is a gold mine.
- stanley 15y ago
  Mind elaborating?
  - moreati 15y ago
    I cannot speak for dr_rezzy, but I wouldn't be surprised if the Skype network experienced more spam following a reimplementation of the Skype protocol. Having control over the behaviour of every client allows Skype the company to more tightly control the behaviour of the network, including automated/bulk messaging. A client that can be freely modified/scripted makes it harder to restrict/filter automated behaviour e.g. spam.
helmut_hed 15y ago
I don't believe that this is (despite stated intent) making Skype "open source". It would be more accurate to say that this work makes it possible to create an open-source wrapper around a proprietary kernel. This wrapper could then be updated as times change to support different platforms, as long as the linkage to the kernel was compatible. This neatly steps around some legal problems because: 1) The wrapper itself is not encumbered (unless some patent issues applied) 2) Users with a legal copy of Skype on one platform can apply the wrapper themselves (though they cannot redistribute the result) You can even imagine distributing (via, say, github) a kit consisting of the wrapper and a tool that applies that wrapper to a user-supplied Skype binary. All legal as far as I know (IANAL etc.)
- gcb 15y ago
  This already happens and is dismissed on the linked blog comments. But i have no idea what it IS then

by martey 15y ago

beza1e1 15y ago

For a clean room reverse engineering they could analyse the Skype binaries to document the protocol.

kogir 15y ago
Clean room requires that those creating the implementation don't have access to the original implementation. Having the same person(s) inspect the binaries and create an implementation fails this requirement. See: http://en.wikipedia.org/wiki/Clean_room_design http://en.wikipedia.org/wiki/Clean_room_design
- skypeopensource 15y ago
  But how can you test if you protocol/document correct? Yes, Epycs code may have question about legit and some other stuff. But after it going to a beta or stable stage. We can use Epycs protocol documentation to write, for example, epycs.java and make it fully "clean room".
  - cwzwarich 15y ago
    You get someone who is not involved with the reverse engineering to test it.
  - dredmorbius 15y ago
    Look up the term "Chinese Wall". What's required (for purposes of courtroom defense) is a clearly documented procedure in which those who have access to the source being reimplemented (the spec writers and testers) NOT be the coders, and vice versa. Another example is the SMB/CIFS reimplementation in the case of Samba. Here, because the protocol was an over-the-wire system, analyzing network packets (not covered by source analysis proscriptions) was sufficient to create a Free Software implementation.
    - deleted 15y ago
      [deleted]
    - skypeopensource 15y ago
      Yeah, we will do it. But now project still at first stage.
rplnt 15y ago
Can't be the protocol itself patented?
- nikcub 15y ago
  that would involve describing it
  - pornel 15y ago
    Describing just one part of it could be sufficient to sue, but not sufficient to develop a client. Software patents are intentionally vague, so I doubt anybody could write a working client based on a patent alone (even if whole protocol was claimed to be described).
    - caf 15y ago
      You are probably correct, but this is an abuse of the patent system, since the quid pro quo for patent protection is the disclosure of the invention to advance the state of the art.

Deinumite 15y ago

Yeah... I don't really understand what their issue is to be honest. It really is up to Skype if they want to release their protocol. You can't really force anyone into being open source. I actually disagree with their methods, its the same as a closed source company violating the GPL when they steal source code like this.

dchest 15y ago
It really is up to Skype if they want to release their protocol. This isn't true. Nothing stops you from analyzing and implementing their protocol. This project, however, is only the first part.
nikcub 15y ago
Reverse engineering has given us so many good things - Samba, OpenOffice, Wine, MAME (and other emulators) the bitkeeper debacle, which gave us git. Then there are all the Linux and UNIX drivers that were written by reverse engineering windows drivers because vendors weren't supporting those operating systems. The guys who reverse engineered Exchange Server were acquired by Cisco. I don't understand why the Skype case is 'evil'. distributing the binaries may violate terms of service, but it isn't illegal in large parts of the world.
- excuse-me 15y ago
  It did also give us the PC running Windows - so there is a dark side ;-) Unless your home PC is an IBM PC-AT it's the result of reverse engineering.

tibbon 15y ago

Remember, open source doesn't mean free. It just means you can view the source.

_delirium 15y ago
That's not the usual use of the term in tech. Even Microsoft, after some initial confusion, has settled on using "shared source" rather than "open source" to describe situations where they share the source but not under an open-source-definition-compatible license.
simonw 15y ago
The Open Source Definition provides a very clear explanation of when the term open source should be used: http://www.opensource.org/osd.html http://www.opensource.org/osd.html
- bigiain 15y ago
  In one sense, I feel "The Open Source Movement" have co-opted a plain english two word phrase. Their introduction there can be rewritten as "Open source doesn't just mean the source is open. We claim there are also implications about the means of distribution." It's as though someone was telling people "free beer" doesn't just mean beer that's free, it also needs to be in glass not cans - free beer in cans needs to be called something else… I think there's a lot of "open source" software out there that is not "open source(tm)". I'm not sure "the open source movement" are doing themselves any favors by aggressively defending their particular definition of a descriptive phrase that is widely known and easy to assume you understand. (But I also understand the need for specific technical meanings in the software field, and that phrases like "open source" end up being part of the field's jargon, and have far more specific technical meanings than the "plain english" deconstruction of the words indicate. I just think the "open source" case has backed itself into a corner where people assume a plain english interpretation of the phrase, then have the "open source movement" people need to jump on them and say "no, you're wrong". As displayed upthread.)
  - djeikyb 15y ago

dr_rezzy 15y ago

For spamming this is a gold mine.

stanley 15y ago
Mind elaborating?
- moreati 15y ago
  I cannot speak for dr_rezzy, but I wouldn't be surprised if the Skype network experienced more spam following a reimplementation of the Skype protocol. Having control over the behaviour of every client allows Skype the company to more tightly control the behaviour of the network, including automated/bulk messaging. A client that can be freely modified/scripted makes it harder to restrict/filter automated behaviour e.g. spam.

helmut_hed 15y ago

I don't believe that this is (despite stated intent) making Skype "open source". It would be more accurate to say that this work makes it possible to create an open-source wrapper around a proprietary kernel. This wrapper could then be updated as times change to support different platforms, as long as the linkage to the kernel was compatible. This neatly steps around some legal problems because: 1) The wrapper itself is not encumbered (unless some patent issues applied) 2) Users with a legal copy of Skype on one platform can apply the wrapper themselves (though they cannot redistribute the result) You can even imagine distributing (via, say, github) a kit consisting of the wrapper and a tool that applies that wrapper to a user-supplied Skype binary. All legal as far as I know (IANAL etc.)

gcb 15y ago
This already happens and is dismissed on the linked blog comments. But i have no idea what it IS then