The communications industry is ready for an infusion of data, such as digital video, to drive it to recovery, but music, video, and other digital-content owners continue to keep a tight rein on their growing mass of IP (intellectual property) while waiting for a secure DRM (digital-rights-management) scheme to materialize. The complexity of DRM, however, makes it a nontrivial addition to a system, especially a consumer device with a low cost threshold.
Several standards are under development to define how to encrypt material and distribute it over public networks. Rather than define the policies themselves, they define a foundation framework that can support a variety of DRM policies. For example, the ISMA (Internet Streaming Media Alliance) 1.0 Encryption and Authentication spec, scheduled for approval this month, describes how to apply the Advanced Encryption Standard (AES) to content and packetize content for distribution in such a way as to prevent a late packet from disrupting the stream.
Intentionally, these specs do not define what keys you should use or how to manage particular rights. One reason for this omission is that the industry is unclear on how you should manage keys or express rights. Key management and expression of rights, however, is where DRM gets the most complex.
The TCP (Trusted Computing Platform) from the TCG (Trusted Computing Group) addresses key management by specifying a trusted module that applications can use to protect content. The module is actually a processing subsystem; all encryption and decryption happens on the module, so keys are never in the clear. However, to decrypt a 2-Mbyte/sec video stream, the module needs significant processing ability. The $4.25 (1 million) AT97SC3201 TPM from Atmel, for example, performs a 2048-bit RSA sign in 500 msec.
Several proprietary DRM schemes are under development. Sony and Philips, among a plethora of hopefuls, have their own architectures. However, the lack of a consistent model for how to pay for content and use it will easily confuse users. Different business models that may restrict use to a single person or device or a specific time period will constrain the use of similar content, such as music files. Such flexibility is great for content owners but requires users to interact differently with every piece of content. Confusion will arise when users think they are buying one form of license and getting another. Buying and using content needs to be as easy as saying “I want it” and clicking on a button. It shouldn’t mean deciding how you want it and having to read pages of small print to understand what you are buying.
Most companies mistakenly believe that content protection is about protecting content. Consider that renting a new video release for a single night costs $4 to $5, but renting an old video for five days costs $5. Most content makes the majority of its revenue in the first few weeks of release. Thus, content protection is really about protecting the release window.
Many companies mistakenly focus on the technology when trying to understand DRM and fail to consider the real social issues that managing content involves. For example, DRM schemes that tie content to a single PC fail to address the needs of, say, a child of divorced parents who lives in two homes. Even more common is the person who wants to play music at home, at work, in the car, on a portable player, and at a friend’s house. The killer app for digital content is the connected home, yet most DRM schemes undermine consumers’ ability to easily move content between devices. Protection isn’t just about security; you need to consider convenience, as well.
It is in these real-world individual issues that DRM will meet the most resistance. Content owners want strict definitions of stealing and honesty. However, schemes that are too difficult to work with or appear insensitive to individual circumstances may drive “honest” people to reconsider what honesty really means.
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