It may be possible under the proposal but is distant from the intended or anticipated uses.
This proposed extension appears to provide a means for distributing keys between DRM chips/implementations (BD+/AACS/etc) and a remote license server. The reason this is a HTML specification extension is that Netflix and Google want to use <video> within HTML -- thus the browser environment must become responsible for interfacing between the DRM implementation and license providers.
Knowing the "keys" being transmitted is not useful because they'll be encrypted using public key cryptography. A heavily protected/tamperproof[1] DRM chip will have access to the actual keys required to decrypt the content. This could take the form of a Trusted Platform Module (TPM) as part of the widely criticised "Trusted Computing" initiative (is this one of the reasons why Microsoft is involved with the proposal?).
Some of the motivations of pushing towards this heavily restricted and inaccessible method of delivering content could include:
1) Ability to lock content to particular devices (iPhone users can access a TV show 2 weeks before anyone else).
2) Taking control over the purchasing cycle of consumers by forcing constant hardware upgrades.
3) Renting content for short durations of time under very specific conditions and limitations.
4) Pricing content on a per-user basis (some users pay more than others for the same content)
This proposed extension appears to provide a means for distributing keys between DRM chips/implementations (BD+/AACS/etc) and a remote license server. The reason this is a HTML specification extension is that Netflix and Google want to use <video> within HTML -- thus the browser environment must become responsible for interfacing between the DRM implementation and license providers.
Knowing the "keys" being transmitted is not useful because they'll be encrypted using public key cryptography. A heavily protected/tamperproof[1] DRM chip will have access to the actual keys required to decrypt the content. This could take the form of a Trusted Platform Module (TPM) as part of the widely criticised "Trusted Computing" initiative (is this one of the reasons why Microsoft is involved with the proposal?).
Some of the motivations of pushing towards this heavily restricted and inaccessible method of delivering content could include:
1) Ability to lock content to particular devices (iPhone users can access a TV show 2 weeks before anyone else).
2) Taking control over the purchasing cycle of consumers by forcing constant hardware upgrades.
3) Renting content for short durations of time under very specific conditions and limitations.
4) Pricing content on a per-user basis (some users pay more than others for the same content)
[1] Security Engineering, Edition 1, Chapter 14 by Ross Anderson - https://www.cl.cam.ac.uk/~rja14/Papers/SE-14.pdf