Memory Fuse Array Access Control Using Secure Authentication Keys
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Solution Overview
Problem
Memory devices face unauthorized access and potential damage from hostile actors exploiting design-for-test functions, leading to irreversible changes in nonvolatile memory elements, which can degrade device performance or functionality.
Innovation Solution
Implementing secure access keys, such as user-defined and manufacturer-defined keys, to control access to nonvolatile memory elements like fuse arrays, using authentication components to compare access keys and permit or prohibit commands based on matching keys, ensuring only authorized access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If design-for-test functions are made accessible for testing and manufacturing purposes, then ease of operation and manufacturing are improved, but security against unauthorized access and potential damage is worsened
Solution Approach 1:
The patent implements access keys and authentication mechanisms beforehand to control who can access design-for-test functions. The authentication component compares provided access keys with stored reference keys before allowing access to test mode, preventing unauthorized access before it can cause harm.
Solution Approach 2:
The patent introduces an authentication component as an intermediary between the host device and the design-for-test functions. This intermediary verifies access keys and controls access to test mode, preventing direct unauthorized access to vulnerable functions while maintaining legitimate testing capabilities.
2Reliability
If access control mechanisms are implemented to prevent unauthorized access, then security is improved, but device complexity increases
Solution Approach 1:
The patent extracts the authentication logic into a separate authentication component that operates independently from the main test control logic. This modular approach implements security without significantly complicating the core test functions, as the authentication component can be integrated as a distinct module.
Solution Approach 2:
The patent applies access control selectively only to design-for-test functions and test mode operations, rather than implementing system-wide security mechanisms. This localized approach provides necessary security for vulnerable functions while minimizing overall device complexity.
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.