Nonvolatile Memory Destruction Verification for Secure Disposal
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Solution Overview
Problem
There is a demand to make data stored in nonvolatile memory unreadable in a short period of time when the memory system is discarded to ensure data security.
Innovation Solution
A memory system that includes a controller and a power supply circuit to apply a destruction voltage to the nonvolatile memory, determining data readability and checking memory destruction by reading and error-correcting data, and optionally using FUSE circuits to disconnect signal lines for data un-readability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a destruction voltage is applied to the nonvolatile memory to make data unreadable, then data security is improved, but the time required to verify destruction and the complexity of the system increase
Solution Approach 1:
The verification process is segmented into multiple stages: initial readability check, destruction voltage application, and post-destruction verification. This segmentation allows the system to manage the complexity of data destruction verification by breaking it into discrete, manageable steps rather than a single complex operation.
Solution Approach 2:
The system performs preliminary actions by storing test data in the nonvolatile memory before applying the destruction voltage. This preliminary data storage enables subsequent verification of whether the destruction was successful, allowing the system to confirm data un-readability without requiring complex external verification mechanisms.
2Reliability
If FUSE circuits are used to disconnect signal lines for data un-readability, then data security is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The FUSE circuits are extracted as separate, dedicated components within the memory device structure. By isolating the data destruction function into specific FUSE circuit elements rather than integrating it throughout the entire memory architecture, the patent simplifies the manufacturing process while maintaining security functionality.
Solution Approach 2:
The FUSE circuits act as intermediary elements between the control circuit and the nonvolatile memory cells. These intermediary FUSE elements can be selectively connected or disconnected to control data access, providing a manufacturable solution that balances security requirements with manufacturing feasibility.
3Measurement precision
If the controller verifies data readability after applying destruction voltage, then destruction accuracy is improved, but the time required for the process increases
Solution Approach 1:
The verification process uses partial action by testing only specific portions of the stored test data rather than attempting to verify every single bit in the nonvolatile memory. This approach provides sufficient confirmation of destruction effectiveness while significantly reducing the time required compared to exhaustive verification methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures data stored in the nonvolatile memory cannot be read, allowing the system to be discarded securely and efficiently.
Implementation Method 1
the power supply circuit applies a destruction voltage to the nonvolatile memory, the controller determines whether first data can be correctly read from a first address in the nonvolatile memory
Implementation Method 2
when a FUSE circuit is used, the FUSE circuit is disconnected to disconnect a signal line, thereby ensuring that data cannot be read
Data Source
AI summary
A memory system includes a first controller, a nonvolatile memory connected to the first controller, and a power supply circuit that applies a voltage to the first controller and the nonvolatile memory. The first controller writes first data to a first address in the nonvolatile memory and instructs the power supply circuit to apply the destruction voltage to the nonvolatile memory. The first controller determines whether the first data can be correctly read from the first address in the nonvolatile memory and checks destruction of the nonvolatile memory based on the determination.