barge: Yes I get the nuances, but...
...let's rehash the whole thing:
There are 2 (TWO) different architectures:
1. THE TCG MODEL
1.1 The TCG (vanilla) model: The TCG model is only about the secure generation, exchange and safeguarding of keys (For many applications this is more than enough).
1.2 In the TCG (vanilla) model computations are done in the unsecured world of the rich OS
1.3 The TCG model does not execute anything - other than cryptographic operations in the TPM - in a secure execution environment.
1.4 Within the TCG model there is no such thing as an applet! Not even a Janus applet
1.5 While, of course, the Janus DRM scheme could/can be hardened with the use of the TPM it still makes the player device a discrete and proprietary device.
2. THE LONGHORN(NGSCB) MODEL
2.1 The Longhorn(LaGrande/SEM) model is one of a secure execution environment.
2.2 In the Longhorn(LaGrande/SEM) model sensitive computations are done in the secure processor partition under the control of the secure kernel OS
2.3 In the Longhorn(LaGrande/SEM) model the TPM 1.2 is all about the secure generation, exchange and safeguarding of keys, just like in the TCG model described above. Longhorn(NGSCB) depends on the non-volatile memory of the TPM to safeguard not only keys but also time-ticks (i.e elapsed time of a content rental process) and other elements that might otherwise be lost when the PC is shut down.
2.4 No applications - not even Janus - will be integrated into Longhorn(LaGrande/SEM) by default. Within the secure execution environment and under the control of the secure kernel OS ANY DRM scheme can be executed. Every DRM scheme is delivered to the secure execution environment via a certified/verified/encrypted applet(program) that contains all the instructions what this applet is/does and what is supposed to be done(computed). This, by the way, applies to every architecture featuring a secure execution environment, including TrustZone...The trick about LaGrande/TrustZone/SEM architectures is that they are application agnostic...and secure!
It is fundamentally wrong to "generally" mix up Longhorn(LaGrande/SEM/TrustZone) with TPMs. They are not the same, they do not do the same, they have different tasks. But Longhorn(LaGrande/SEM/TrustZone) requires a TPM as spelled out in Point 2.3
Other than that I have no issues...and, yes, I know exactly what Wildman is conveying in his post...and if it takes an "association of Longhorn - TPM" to explain Trusted Computing... then fine with me...
