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Bitfrost: the OLPC security model

Bitfrost: the OLPC security model

Posted Feb 10, 2007 8:01 UTC (Sat) by bronson (subscriber, #4806)
In reply to: Bitfrost: the OLPC security model by man_ls
Parent article: Bitfrost: the OLPC security model

DRM can be used with anything, not just copyrighted content (according to anyway). When the OLPC turns into a brick, isn't that awfully similar to a DVD refusing to decript its content or a Vista computer refusing to run an executable? Sure seems it to me.

And both DRM and Bitfrost are very dissimilar to chmod a-rw ~/. Directory permissions don't involve a 3rd party, DRM and Bitfrost do, chmod a+rw ~/* undoes the damage; DRM and Bitfrost don't have any such exit, etc. Shall I continue?

I guess we'll just have to agree to disagree on this one.

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Posted Feb 10, 2007 10:21 UTC (Sat) by man_ls (guest, #15091) [Link]

As the linked page takes pains to explain, DRM can be based (on computers) upon "Trusted Computing", which Stallman mimics as "Treacherous Computing". You are saying that DRM can be used for anything (and is indeed used on the OLPC), when in fact it is TM that you are speaking about. It seems like a pedantic point, but it is important for the discussion not to mix these concepts IMHO.

TM can be a chip used by the kernel with cryptographic keys under the control of the owner, in which case it can be a good thing. The keys can also be under the control of a third party, which is a disaster. In the case of the OLPC it can turn into a brick. As it is a government-sponsored program anyway, I guess they have thought about it: if it gets disabled by mistake, you can always take it to a hypothetic repair service. I personally don't like the idea, and think it is a weak point in the whole scheme, but inexplicably nobody asked me before implementing it ;)

DRM, as one of its main peddlers has just said, is always a bad idea. Notice that, in the case of a DVD player you don't even need TM, as it is a closed platform anyway; in this case the device can simply have its keys revoked and it will refuse to play protected content, which is different than turning into a brick. When it is a computer in disguise you need complicated schemes such as TM to make the device obey its true master, the manufacturer.


Posted Feb 10, 2007 20:03 UTC (Sat) by bronson (subscriber, #4806) [Link]

TC is now such a broad concept that it's nearly useless. The wikipedia page does make it sound like both Bitfrost and drectory permissions would fall under the TC umbrella. But so would AppArmor. And hardware virtualization extensions. That doesn't mean they have anything in common with each other.

We can at least agree that FairPlay, CSS, and Microsoft's incompatible flavor du jour are examples of DRM, yes? defectivebydesign says that Tivoization is a form of DRM. And Hasp HL claims to be DRM. Bitfrost's ultimate behavior is basically the same as these technologies and has only the most superficial resemblance to directory permissions. That's why I really don't think it's a stretch to consider it DRM.

Maybe you could point me to an authoritative definition of DRM? The definition at the top of the Wikipedia entry clearly includes Bitfrost but, alas, I'd hardly call it authoritative.

Perhaps the media is subverting the meaning of DRM like it did with hacker? At this point, though, I'm afraid the cat's pretty far out of the bag.


Posted Feb 10, 2007 20:27 UTC (Sat) by bronson (subscriber, #4806) [Link]

...*not a stretch* to call [Bitfrost] DRM. Gah.


Posted Feb 10, 2007 23:01 UTC (Sat) by man_ls (guest, #15091) [Link]

I would say that Trusted Computing is a well defined concept, or at least it was until vendors started marketing it. OTOH DRM was always snake oil, and still is today. Maybe that is why authoritative definitions are hard to find. Look at this one (in PDF):
Digital Rights Management (DRM) is a system to protect high-value digital assets and control the distribution and usage of those digital assets.
It comes from an academic paper, but the "high value" part is not very objective: DRM can also be used for low-value garbage.

As to the examples you cite: Tivoization is a form of DRM only because it is used to protect digital content (digitized TV in this case). The article in Dr Dobb's Journal talks about protection of content and restriction of document distribution.

Even if the press and the general public misuse the term, that is IMHO no excuse for spreading bad usage. DRM protects content by whatever means, even if it's just a remotely controlled daemon setting directory permissions. After all, Adobe's protected PDF's rely on something like a bit set on a file.

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