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Communications Microsoft Technology

Skype Protocol Has Been Reverse Engineered 231

An anonymous reader writes "One researcher has decided he wants to make Skype open source by reverse engineering the protocol the service uses. In fact, he claims to have already achieved that feat on a new skype-open-source blog. The source code has been posted for versions 1.x/3.x/4.x of Skype as well as details of the rc4 layer arithmetic encoding the service uses. While his intention may be to recreate Skype as an open source platform, it is doubtful he will get very far without facing an army of Microsoft lawyers. Skype is not an open platform, and Microsoft will want to keep it that way."
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Skype Protocol Has Been Reverse Engineered

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  • by mailman-zero ( 730254 ) on Thursday June 02, 2011 @03:43PM (#36323986) Homepage
    Just because the protocol is reverse engineered doesn't make it open. I would rather see an open standard become supported or used by Skype/Microsoft.
  • FTFA (Score:5, Insightful)

    by cultiv8 ( 1660093 ) on Thursday June 02, 2011 @03:45PM (#36324008) Homepage

    The remaining question to ask is what’s the point of doing this reverse engineering? Skype is a free-to-use service for the most part. You do pay for non Skype-to-Skype calls, and have to use the official software, but is that really enough to make users desire an alternative?


  • by fuzzyfuzzyfungus ( 1223518 ) on Thursday June 02, 2011 @03:54PM (#36324136) Journal
    Unless there is a substantial amount of client-trusting going on(which would be incredibly stupid; but not entirely out of the question given that Skype makes heavy use of random machines running Skype to save the operator bandwidth and machine time), I suspect that having the protocol won't be of too much use for theft of service. Even using a 3rd party client, you'd still need credentials tied to an account with money in it, and Skype can always bounce you at the points where their network meets the POTS/Cell system.

    Again, unless analysis of the protocol reveals deep, exploitable, flaws I'm guessing that MS won't care too much. The world already has at least one born-open VOIP protocol(SIP), quite possibly several, and those haven't been a deep threat to Skype because they are comparatively hard for neophytes to set up, have firewall issues, etc. Heck, Microsoft bought Skype despite having a voice chat system in MSN. Voice chat over the internet, while not trivial, just isn't some super trade secret, nor is it what makes Skype a contender.

    Now, given the reports of how slimy and secretive the Skype binary can be, I'd be happy to see an open implementation; but I suspect that the possibility won't rock the boat from MS' perspective...
  • by fuzzyfuzzyfungus ( 1223518 ) on Thursday June 02, 2011 @03:57PM (#36324168) Journal

    Oh, wait, you needed to talk to somebody who is using Skype. Shit.

    Network effects are a nuisance; but you just can't dismiss them. It would, indeed, be rather perverse to use reverse-engineered secret protocols as the basis for new systems where open ones are available(SIP, XMPP, etc, etc.); but if you want to interact with the userbase of a proprietary protocol your options are either to reverse engineer it, or to accept whatever T and Cs the proprietary software decides to impose.
  • by doti ( 966971 ) on Thursday June 02, 2011 @04:06PM (#36324262) Homepage

    the question here is not the protocol/technology, but the userbase.

    you can't use jingle to talk to all your friends running skype.

  • by Jozza The Wick ( 1805012 ) on Thursday June 02, 2011 @04:40PM (#36324644)
    You think my sister or my not-very-computer-saavy parents are going to do that so I can continue to video chat with my niece in the UK? No. Understandably so (although of course I'd love them too), they have lots of other demands on their time. Plus, no motivation from their end. Why should they go through all that hassle (for them), just to maintain the status quo? No, what we really need is a open source client that can talk to native Skype clients. So this isn't a waste at all, for those using Skype with non-techy friends & family... It's the critical mass effect.
  • by node 3 ( 115640 ) on Thursday June 02, 2011 @05:29PM (#36325352)

    Ease of use might have something to do with it, but ease of development is entirely unrelated.

    Thank you for so succinctly summing up the single greatest problem with Linux and most other open source software.

    Ease of use *IS* part of development. It's just as much a requirement as any other technical aspect.

    Also, like most nerds, you have vastly underestimated the difficulty in developing an application. It's easy to whiteboard a simple voice chat app, and *fairly* simple to create some sort of intercom-type chat program. But once you start adding things like central directories, low-latency variable bandwidth calling over the internet, and the like, you end up with difficulty even coming up with a reasonable whiteboard outline, and the actual implementation becomes quite difficult. By no means impossible, but it's not something you'll bang out over a weekend and be on par with something like Skype.

    As awful as Skype may be, just because you understand the idea behind how it works doesn't mean it's easy to duplicate. This is a classic nerd mistake.

Any sufficiently advanced technology is indistinguishable from a rigged demo.