Memory Device Secure Access Key Fuse Array Authentication
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Solution Overview
Problem
Memory devices face challenges in securing access to nonvolatile memory elements, particularly the fuse array, to prevent unauthorized or accidental modifications that can damage the device, as existing security measures are inadequate in controlling access to test modes and special features.
Innovation Solution
Implementing a secure access key system where a user-defined access key or a manufacturer-defined access key is stored in the fuse array, allowing only authenticated access to the fuse array and other secure features, using authentication components to compare received access commands with the stored key and control access accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If access to the fuse array is restricted to prevent unauthorized modifications, then device reliability is improved, but ease of operation deteriorates due to limited access control
Solution Approach 1:
The patent implements access control by changing the parameter of access authentication - requiring an authentication key to be provided before allowing access to the fuse array. This parameter change enables differentiated access levels where authorized operations can proceed while unauthorized modifications are blocked, thus improving reliability without completely restricting legitimate access
2Manufacturing precision
If authentication key verification is implemented for fuse array access, then manufacturing precision is improved through controlled access, but device complexity increases due to additional authentication components
Solution Approach 1:
The patent segments the access control function into separate authentication components that verify the authentication key independently from the fuse array programming function. This segmentation allows the authentication logic to be implemented as a distinct module, managing complexity by separating concerns while ensuring precise control over who can modify the fuse array during manufacturing
3Loss of information
If secure access control is implemented to prevent unauthorized modifications, then loss of information is reduced, but ease of manufacture deteriorates due to additional security measures
Solution Approach 1:
The patent introduces an authentication key as an intermediary mechanism between the programming device and the fuse array. This intermediary verifies the identity and authorization of the programming device before allowing access, preventing unauthorized modifications that could cause information loss while maintaining a relatively simple manufacturing process for authorized devices
Data Source
AI summary
Memory devices, systems including memory devices, and methods of operating memory devices are described, in which security measures may be implemented to control access to a fuse array (or other secure features) of the memory devices based on a secure access key. In some cases, a customer may define and store a user-defined access key in the fuse array. In other cases, a manufacturer of the memory device may define a manufacturer-defined access key (e.g., an access key based on fuse identification (FID), a secret access key), where a host device coupled with the memory device may obtain the manufacturer-defined access key according to certain protocols. The memory device may compare an access key included in a command directed to the memory device with either the user-defined access key or the manufacturer-defined access key to determine whether to permit or prohibit execution of the command based on the comparison.