US 2021/0200882 A1 · Device, System, and Method of Policy Enforcement for Rich Execution Environment

Abstract

Device, system, and method of policy enforcement for rich execution environment. An electronic device includes a Trusted Execution Environment (TEE), a Rich Execution Environment (REE), and a hardware-based secure sub-system which includes a cryptographic engine. The REE includes a cryptographic driver configured to initiate a request for TEE authorization to perform a particular cryptographic operation by the cryptographic engine on a data-item that is stored in a memory region that is accessible by the REE. The TEE includes a policies manager to determine whether the request from the REE is approved or rejected, and if approved, to inject data-items into the secure sub-system to enable performance of the requested cryptographic operation by the cryptographic engine.

Claims20

Dependent claims

An electronic device comprising:

a Trusted Execution Environment (TEE) to securely execute code;
a Rich Execution Environment (REE) to execute code;
a hardware-based secure sub-system which comprises a cryptographic engine able to perform cryptographic operations;
wherein the REE comprises a cryptographic driver configured to initiate a request for TEE authorization to perform a particular cryptographic operation by the cryptographic engine on a data-item that is stored in a memory region that is accessible by the REE;
wherein the TEE comprises a policies manager to determine whether said request from the REE is approved or rejected, and if approved, to inject one or more data-items into said secure sub-system to enable performance of said particular cryptographic operation by said cryptographic engine in the secure sub-system.

2 more elements

A processing system comprising:

a Trusted Execution Environment (TEE) to securely execute code, wherein the TEE is co-located near a Rich Execution Environment (REE);
wherein the TEE comprises a trusted Digital Rights Management (DRM) application, configured to establish a particular DRM session between the TEE and a DRM playback application of the REE;
wherein the TEE comprises a policies manager unit, (i) to receive from a secure sub-system of the processing system an interrupt indicating a request to authorize a particular DRM-related cryptographic operation by said secure sub-system on a content-item that is stored in unsecured unprotected memory that is dynamically managed by the REE, (ii) to verify said request based on data obtained by the policies manager unit from a co-located policies database within the TEE, (iii) to authorize said request by writing via a hardware interface one or more parameters into one or more shadow registers of the secure sub-system which are accessible by a cryptographic engine, said one or more parameters enabling said cryptographic engine of the secure sub-system to perform said particular DRM-related cryptographic operation.

A method implementable by a processing system that comprises a Trusted Execution Environment (TEE) co-located with a Rich Execution Environment (REE), the method comprising:

performing a Digital Rights Management (DRM) handshake, to establish a particular DRM session between (i) a DRM playback application in the REE and (ii) a trusted DRM application in the TEE;
storing, in a secure sub-system of said processing system that is accessible by both the REE and the TEE, one or more descriptors of a requested DRM operation that is requested by said DRM playback application of the REE;
wherein said storing of the one or more descriptors triggers a sending of an interrupt to a policies manager unit in the TEE, wherein the interrupt indicates a request by the REE to obtain TEE authorization to perform said requested DRM operation;
evaluating said request by said policies manager unit within the TEE, based on (i) one or more DRM policies that are securely stored in a co-located policies database within the TEE, and (ii) a DRM key index and other descriptors of said requested DRM operation, that are inserted by the REE into slots in the secure sub-system;
if said request is evaluated as authorized, then:
(I) inserting by the policies manager of the TEE, via a hardware interface, into one or more slots in the secure sub-system, one or more parameters that enable a cryptographic engine in the secure sub-system to perform said requested DRM operation;
and (II) sending a request authorization message from the policies manager unit of the TEE to the cryptographic engine in the secure sub-system.

4 more elements

Dependencies are inferred from the claim text.

Device, System, and Method of Policy Enforcement for Rich Execution Environment

Life of this patent

Device, System, and Method of Policy Enforcement for Rich Execution Environment

Life of this patent

Abstract

Claims20