Secure Execution Environment for Policy Integrity and Adaptability
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Solution Overview
Problem
Conventional security policy systems in electronic devices are inflexible and difficult to update, as they require a single digital signature from the manufacturer, leading to all devices receiving the same updates without individualization, making it challenging to adapt to different devices or user needs.
Innovation Solution
Implementing a secure execution environment in a discrete circuit separate from the processor to verify and apply security policies, allowing for easier and more secure updates, enabling individual device policy changes and feature modifications without system configuration updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the security policy is included in the boot image with a single digital signature, then the integrity and authenticity of the policy are protected, but the policy cannot be easily updated or individualized for different devices
Solution Approach 1:
The patent segments the security policy from the boot image binary. Instead of embedding the policy within the signed boot image, the policy is stored separately in a file system accessible by the kernel. This allows the policy to be updated independently without requiring a new signed boot image, resolving the contradiction between maintaining integrity through signing and enabling easy updates.
Solution Approach 2:
The security policy is extracted from the boot image and placed in a separate accessible location (file system). The kernel can load and apply the policy without it being part of the boot image binary. This extraction enables individual devices to have customized policies while the boot image signature remains intact for authentication.
2Adaptability or versatility
If the entire boot image is updated to change security policy, then the policy can be updated, but the update size is large and requires extensive system configuration changes
Solution Approach 1:
By extracting the security policy from the boot image binary and storing it separately in the file system, the patent enables updating only the policy file itself rather than the entire boot image. This dramatically reduces the update package size from megabytes (entire boot image) to kilobytes (policy file only).
Solution Approach 2:
The patent segments the security policy into a separate updateable component independent of the boot image. This allows the policy to be updated as a small, standalone file without requiring system configuration changes or large package updates, resolving the contradiction between update capability and update size.
3Reliability
If the security policy is hard coded in a signed memory portion, then the policy integrity is protected, but individual device changes cannot be made
Solution Approach 1:
The patent extracts the security policy from the hard-coded, signed memory portion and places it in a separate file system location. This allows each device to have its own customized policy file while the kernel maintains integrity verification through cryptographic signatures on the policy files themselves, enabling individual device changes without sacrificing integrity protection.
Solution Approach 2:
The patent segments the policy delivery mechanism into two parts: the signed boot image that provides initial authentication, and separate signed policy files that can be individually customized per device. This segmentation allows integrity protection through signing while enabling individual device customization through separate policy files.
Data Source
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AI summary
The invention relates to an electronic device comprising a processor configured to operate a kernel of an operating system, a secure execution environment configured to protect the integrity and authenticity of a security policy. The secure execution environment is configured to receive a security policy, verify the integrity and authenticity of the security policy, transmit the verified security policy to the kernel. The kernel is configured to apply the verified security policy to the electronic device. The invention relates to a method in an electronic device and a computer program with a program code for performing the method.