Fred wrote: > Technically of course you are right, it could be done. The licensing can clearly be done, But I'm not sure that the needs can be met.
> But DRM is different in that it needs to grant access in what is > essentially a hostile environment (the user's home). In PGP or even > banking applications, you are unlikely to want third parties to access > the secret, In all modern cryptography, the fundamental concern starts with the assumption that the parties want to transfer data securely. The code to do this is published and well known, the security relies upon the secret (usually called a key). Anything else is called SBO, Security By Obscurity, and is considered trivial to break. The infamous deCSS DVD hack relied upon bad practices for the key management used to decrypt the DVD. Proper key management is hard. > You don't care if someone "steals" digital music you bought since you > still have it after the "theft". This is usually called the "Playboy in the frat house" model. The publisher usually wants only one 'house' to read the magazine, but clearly in a frat house, the copy of Playboy can get passed around, depriving the publisher of income. But it is not a major problem, as the subscription fee is only part of the business model, the advertisers pay the rest and usually the majority. So all the frat brothers see the ads, and everyone is happy. It is harder for digital goods. Copy protection is hopeless. See Superdistribution. Objects as Property on the Electronic Frontier. by Brad Cox. Addison Wesley Publishing Company ISBN: 0-201-50208-9 for a more rational approach. If there is no advertising revenue stream to back up the subscription, it is very hard to make it all work. > I don't see how an open source > solution could provide the least bit of assurance it can protect a key > it has to know to do its job... Another rule of serious security is that if the bad guy has access to the physical device, it is next to impossible to provide security. If the 'key' is kept on a computer hard drive/disk then once you pull the drive out of the box, you can apply exhaustive search techniques. These are trivial unless: 1) the key is strongly encrypted using some other key 2) the key is kept in hardware that is resistant to replay attacks. Clearly approach #1 just replaces the music playing key problem with another key finding problem. No real change. Most users use really wimpy passwords. See http://www.pfarrell.com/technotes/lamepasswords.html or http://www.cert.org/advisories/CA-2003-08.html And while approach #2 seems ideal, the DVD player manufacturers did it badly, leading to the deCSS crack. Doing it properly is hard. The Intel P3 had a hardware processor ID, which would have helped, but that feature caused an uproar and was dropped. So if you have a security system, where only one of the parties wants to transfer data securely, and the other wants to cheat, it is a really hard problem. Open source and licensing issues are really not the hard part. Its the lust in your heart. -- Pat http://www.pfarrell.com/music/slimserver/slimsoftware.html _______________________________________________ Discuss mailing list Discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
