The next document format battleground

These questions are valid, they deserve full consideration. But they may also, to an extent, be missing the real point. It is entirely possible that the document format battles are done; even if OpenXML is not a perfect standard, it is far more open than its predecessors. While Microsoft is not inclined to make life easy for those who would interoperate with its file formats, the company may well have realized that obscure formats have outlived their usefulness as a way of maintaining desktop domination. This might just be a battle we have won, even if the victory is rather more messy than we would like.

Before we charter an aircraft carrier for our "mission accomplished" party, however, it is worth reflecting on different forms this fight could take in the future. Cory Doctorow gave us a good hint in this InformationWeek article on "information rights management." IRM is a feature touted by Microsoft for a few years now which has the potential to complicate life considerably in the future.

IRM offers some interesting features to people who are worried about the information they put into their documents, presentations, and spreadsheets. With IRM, the document owner can specify exactly who can read a particular file, and under what conditions. Access can have an expiration time attached to it - or it can be revoked at any time. Actions like printing can be restricted. For anybody who feels the need to control information, these features cannot fail to be appealing.

But these features only work if the client plays along, and free software clients have not always distinguished themselves in this area. Or, rather, they have distinguished themselves very well by serving the needs of their users. Even if a programmer implements the "this document can only be printed once" flag, somebody else, perhaps after having lost their one printing opportunity to a particularly nasty paper jam, will hack it out. Clearly, Microsoft must prevent the creation of free applications which can read IRM-protected documents or it will be unable to live up to the promises it has made for that technology.

Microsoft has a couple of weapons at its disposal (beyond pure obscurity) which can be used against any potential free IRM implementation. One is the DMCA, which, in the US (and countries which have implemented similar laws), can be employed against those who bypass access restriction mechanisms. Anybody who posted code that, say, allowed the user to cut and paste text out of an IRM-protected document would likely face an unpleasant reception in the US. They would be in a situation much like that faced by Dmitry Sklyarov, who bypassed similar restrictions in PDF files, a few years ago.

Of course, the Sklyarov case did not necessarily work to Adobe's advantage in the end, and Microsoft might wish to avoid a similar storm of bad publicity. So, as Cory's article points out, Microsoft might pursue a different option: the use of the trusted computing module (TPM) increasingly being built into new computers. With the remote attestation feature of the TPM, it is possible to refuse to pass decryption keys to any system which cannot be shown to be running approved software. This system would be quite tight and hard to defeat - it might just work. And it would no longer matter how "open" the document format is.

The full remote attestation scenario requires the cooperation of the entire system, starting with a "secure" BIOS which initializes the TPM properly. Most systems do not currently operate in this mode, so the realization of this threat will not happen in the immediate future. One should not, however, forget that the TPM has been designed to support just this mode of operation. It does not take all that much paranoia to imagine that these capabilities will not go unused forever. "Trusted computing" has yet to touch most of us, but we ignore it at great risk. Among other things, it could make the current discussion of open document formats entirely moot.