Secure Page Table Tree for Nonvolatile Memory Data Integrity
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Solution Overview
Problem
Nonvolatile memory devices are vulnerable to data theft and falsification during power down, as they can be physically accessed and manipulated externally, posing a significant threat to information processing devices, especially those used outside or in insecure locations.
Innovation Solution
A memory management device with a secure page table tree and verifier tree structure, where data and verification information are stored in a secure internal memory and external memory, ensuring data integrity by verifying and updating verification information to prevent unauthorized access and falsification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nonvolatile memory is used to enable high-speed boot and low energy consumption, then productivity and energy efficiency are improved, but data security deteriorates because the memory remains accessible during power down
Solution Approach 1:
The patent divides the memory system into secure and non-secure regions, with the nonvolatile memory segmented into protected areas (storing verification information) and accessible areas (storing data). This segmentation allows the system to maintain the productivity benefits of nonvolatile memory while isolating critical security functions in protected zones that prevent unauthorized access during power down.
Solution Approach 2:
The patent introduces verification information (hash values, MAC values) as an intermediary mechanism between the data storage and security verification processes. This intermediary layer enables the system to safely utilize nonvolatile memory for high-speed boot while the verification mechanism mediates security checks to prevent data theft and falsification.
2Device complexity
If verification information is stored in the same location as data, then device complexity is reduced, but reliability deteriorates because both data and verification information may be falsified together
Solution Approach 1:
The patent segments the storage locations for data and verification information into distinct protected and non-protected areas. Verification information is stored in secure regions that are protected from unauthorized writing, while data resides in accessible regions. This spatial segmentation ensures that even if data is compromised, the verification information remains intact and can detect the falsification.
Solution Approach 2:
The patent applies different security qualities to different parts of the memory system. Critical verification information is placed in locally protected areas with restricted write access, while general data can be stored in more accessible areas. This local quality differentiation allows the system to maintain reliability by protecting only the essential verification components rather than the entire storage system.
3Reliability
If a secure area is provided for storing verification information, then reliability is improved, but device complexity increases due to additional secure storage requirements
Solution Approach 1:
The patent merges the secure storage functionality with the existing nonvolatile memory structure by designating specific regions within the nonvolatile memory as protected areas. Rather than adding completely separate secure hardware modules, the solution combines security functions with the available memory architecture, using the same physical memory device but with differentiated access controls and protection mechanisms.
Solution Approach 2:
The patent makes the nonvolatile memory serve multiple functions: it acts as both the primary data storage medium and contains embedded secure regions for verification information. This multi-functionality reduces the need for separate dedicated secure storage hardware, thereby limiting the increase in device complexity while still providing the reliability benefits of protected verification storage.
Data Source
AI summary
In one embodiment, a device executes reading and writing for a storage unit storing a table tree and verifier tree. The table tree includes a parent table and child table. The verifier tree includes a parent verifier associated with the parent table, and a child verifier associated with the child table. The parent verifier is used for verifying the child table and child verifier. The device stores a secure table tree being a part of the table tree and used for address translation, and a secure verifier tree being a part of the verifier tree, to a secure storage unit. The device executes verification, based on verification information calculated based on a first child table and first child verifier in the storage unit and a first parent verifier in the secure verifier tree.