OTP Memory Security Controller Lock Status Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor memory devices lack effective mechanisms to prevent the forgery or modification of important data stored in OTP arrays, which are critical for security functions.
Innovation Solution
A semiconductor memory device with an OTP device controller that determines the lock/unlock status of data and prohibits the lock status from being changed to an unlock status, using an OTP register and lock register to prevent external manipulation, and a write driver to manage program and read operations based on these statuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lock-status unit cells are used to prevent important data from being modified, then data security is improved, but the device cannot be re-programmed once locked
Solution Approach 1:
The memory array is segmented into OTP (One-Time Programmable) areas and re-programmable areas. The OTP areas contain lock-status unit cells that prevent modification, while other areas remain freely programmable. This segmentation allows the device to simultaneously provide data security for critical information and re-programmability for non-critical data.
Solution Approach 2:
Different regions of the memory device have different properties: OTP areas have permanent lock-status to ensure data security, while non-OTP areas maintain standard read/write capabilities. This local differentiation allows simultaneous fulfillment of security requirements and operational flexibility.
2Reliability
If OTP array is used to store security data, then data integrity is improved, but the device lacks mechanism to prevent external manipulation
Solution Approach 1:
The device performs preliminary verification of lock-status before allowing any programming operation. The controller checks whether unit cells are in lock-status prior to programming attempts, and prevents programming operations on locked cells. This preliminary anti-action blocks external manipulation before it can compromise data integrity.
Solution Approach 2:
The device implements a feedback mechanism where the controller continuously monitors the lock-status of unit cells and provides feedback to control programming operations. When lock-status is detected, the controller prevents further programming attempts, creating a closed-loop protection system against external manipulation.
3Adaptability or versatility
If all unit cells are made programmable, then device flexibility is improved, but security data can be forged or modified
Solution Approach 1:
The memory device is divided into OTP areas with lock-status unit cells for security data and non-OTP areas for general data storage. This segmentation ensures that security-critical data remains protected while other data can be freely programmed and modified.
Solution Approach 2:
Specific regions are designated with permanent lock-status properties to protect security data, while other regions maintain standard programmability. This local quality differentiation allows the device to simultaneously achieve high flexibility and strong security protection.
Data Source
AI summary
A semiconductor memory device includes a security controller. When a one time programmable (OTP) device is programmed, the semiconductor memory device prohibits lock-status information pre-stored in an OTP lock register from being changed to an unlock status, such that it increases the stability of data stored in an OTP area. The semiconductor memory device includes an OTP device configured to determine whether or not data is changed according to a lock/unlock status when a program command is received, and an OTP controller configured to prohibit the lock status from being changed to the unlock status.