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Skype protocol reverse engineered, source available

skype-open-source.blogspot.com

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Re: Skype protocol reverse engineered, source available

#31

Post by michael_dorfman »

barrkel wrote: post #21
michael_dorfman wrote: post #17

Earlier quoted context omitted.

Actually, as I've said elsewhere, one easy way of protecting a protocol is to explicitly restrict the right to reverse engineer in in the Terms of Service of the client that implements the protocol. Without that client, there's nothing to reverse engineer.

I'm not sure that's necessarily enforceable everywhere; it can be interpreted as an illegal barrier to competition.

That might be true; but do you want to be responsible for hiring the team of lawyers to go head-to-head against Microsoft's lawyers on that point?

Re: Skype protocol reverse engineered, source available

#32

Post by zhyder »

Animus7 wrote: post #18

If the goal is to open up Skype, this isn't the way. Even if some insane insomniac de-twiddles the pages upon pages of optimized indirection in this code (which I seriously doubt), all Skype has to do is tweak the protocol or encryption and the researcher is back to square one. It's a losing battle. And that's not even getting into the legality of it it all. How about instead of trying to fruitlessly crack Skype, we…

It's not that easy for Skype to tweak their protocol, since they have to ensure that slightly older installed versions continue to interoperate.

Re: Skype protocol reverse engineered, source available

#33

Post by fractalcat »

_delirium wrote: post #10
michael_dorfman wrote: post #5

Earlier quoted context omitted.

That still doesn't mitigate the need for lawyers. The protocol is still intellectual property, and reverse engineering it may not be without consequences.

I don't believe it's possible to secure any sort of intellectual-property protection for a mere protocol. The usual way of protecting them, though, is to patent some essential feature needed to implement the protocol, which may or may not be the case here.

I think there's a potential precedent in the reversing of the original PC BIOS - it was deemed that what was effectively a reimplementation of a closed protocol was permissible.

And, IIRC, there are still mixed results regarding the extent to which EULAs are enforcible.

Re: Skype protocol reverse engineered, source available

#34

Post by dmc »

michael_dorfman wrote: post #17
_delirium wrote: post #10

Earlier quoted context omitted.

I don't believe it's possible to secure any sort of intellectual-property protection for a mere protocol. The usual way of protecting them, though, is to patent some essential feature needed to implement the protocol, which may or may not be the case here.

Actually, as I've said elsewhere, one easy way of protecting a protocol is to explicitly restrict the right to reverse engineer in in the Terms of Service of the client that implements the protocol. Without that client, there's nothing to reverse engineer.

What about if a developer were to now download the source code available here? Could they, in theory, develop with it as they've never attempted to reverse engineer it themselves?

By using ToS, you're limiting enforcement to the people who do the RE, rather than an implementation, surely?

Re: Skype protocol reverse engineered, source available

#37

Post by unicornporn »

michael_dorfman wrote: post #5
crocowhile wrote: post #4

Earlier quoted context omitted.

I think that claim would be better off if rephrased as "my aim is to make a skype compatible open source software"

That still doesn't mitigate the need for lawyers. The protocol is still intellectual property, and reverse engineering it may not be without consequences.

This being illegal in the US does not mean it is illegal everywhere. People (Americans?) often seem to forget this. US law is not world law.

Re: Skype protocol reverse engineered, source available

#39

Post by jcr »

dmc wrote: post #34
michael_dorfman wrote: post #17

Earlier quoted context omitted.

Actually, as I've said elsewhere, one easy way of protecting a protocol is to explicitly restrict the right to reverse engineer in in the Terms of Service of the client that implements the protocol. Without that client, there's nothing to reverse engineer.

What about if a developer were to now download the source code available here? Could they, in theory, develop with it as they've never attempted to reverse engineer it themselves? By using ToS, you're limiting enforcement to the people who do the RE, rather than an implementation, surely?

Actually, no. If you look at those files, you're "tainted" and can't be the one who writes a new implementation. The correct way to do reverse engineering for compatibility is to have to completely separate teams. The first does the reverse engineering and writes the specification/documentation. The second completely separate teams takes the specs/docs and writes an entirely new implementation.

This is the process used to achieve the "IBM PC Compatible" system you're probably using right now (including your Mac). Reading up on the development of the Compatibles is a good way to understand how to do reverse engineering correctly.

Re: Skype protocol reverse engineered, source available

#40

Post by praptak »

michael_dorfman wrote: post #17
_delirium wrote: post #10

Earlier quoted context omitted.

I don't believe it's possible to secure any sort of intellectual-property protection for a mere protocol. The usual way of protecting them, though, is to patent some essential feature needed to implement the protocol, which may or may not be the case here.

Actually, as I've said elsewhere, one easy way of protecting a protocol is to explicitly restrict the right to reverse engineer in in the Terms of Service of the client that implements the protocol. Without that client, there's nothing to reverse engineer.

The extent to which ToS are enforcible has to be tested yet, especially wrt people who aren't even using the client. I mean hackers who just take advantage of the information released by someone who actually broke the ToS. How are they even bound by the ToS?
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