Unique Digital Signature Generation Using Memory Cell Threshold Voltages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems for securing embedded systems with non-volatile memory are vulnerable to hacking and cloning due to reliance on external entropy sources and lack of a physically unclonable unique identifier.
Innovation Solution
A method for generating a unique digital signature using variations in threshold voltages of native memory cells as an entropy source, concatenated with another internal entropy source, to create a physically unclonable identifier for securing memory devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external entropy sources are used to generate unique identifiers, then the identifier can be generated, but the system becomes vulnerable to hacking and cloning attacks
Solution Approach 1:
The patent extracts the entropy source from external facilities and relocates it entirely within the memory device. The unique identifier is now generated using only internal memory cell characteristics and internal entropy sources, eliminating the security vulnerability of external entropy sources while maintaining the ability to generate unique identifiers.
Solution Approach 2:
The patent introduces native memory cell threshold voltage variations as an intermediary physical layer between the hardware and the unique identifier generation. This physical intermediary provides a tamper-resistant entropy source that cannot be accessed or manipulated by external attackers, thereby securing the identifier generation process.
2Ease of operation
If unique identifiers are programmed at fabrication facilities, then identifiers are available for use, but the identifiers can be stolen during provisioning operations
Solution Approach 1:
The patent performs preliminary action by generating the unique identifier at the earliest possible moment - during the first power-up of the memory device - rather than during fabrication or provisioning. This ensures the identifier is available for immediate use while never exposing it to external facilities where theft could occur.
Solution Approach 2:
The memory device performs self-service by generating its own unique identifier using internal resources (native memory cell variations and internal entropy sources) without requiring external entropy sources or provisioning operations. This eliminates the security risk of identifier theft during provisioning while ensuring identifier availability.
3Quantity of substance
If NVM is implemented externally as a discrete device, then larger or high performance memory is achieved, but the NVM becomes more vulnerable to snooping attacks and side-channel attacks
Solution Approach 1:
The patent applies local quality by implementing security measures specifically within the NVM device itself. The unique identifier generation is localized to the NVM using native memory cell characteristics and internal entropy sources, creating a secure enclave within the external memory device that is resistant to snooping and side-channel attacks while maintaining the memory capacity and performance benefits of external NVM implementation.
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
Enhances data security by generating a unique identifier that is physically unclonable and resistant to hacking, providing improved protection for embedded systems.
Implementation Method 1
obtaining a binary entropy string using variations of threshold voltages (VT) for a number of native memory cells as an entropy source
Implementation Method 2
concatenating the binary entropy string with another binary number including a second plurality of binary bits obtained from a second entropy source internal to the memory device
Data Source
AI summary
A system and method are provided for generating Unique Digital Signatures (UDS) for semiconductor memories to improve data security. Generally, the method involves allocating a number of native memory cells in a memory device; obtaining a multibit binary entropy string (BES) using variations of threshold voltages (VT) of the allocated cells as an entropy source; and mathematically manipulating the BES to generate the UDS. Optionally, the BES can be concatenated with another multibit binary number from a second entropy source internal or external to the memory device, and the result of the concatenation mathematically manipulated to generate the UDS. In one embodiment, a reference voltage is located at a median VT for the cells, and the BES is obtained by reading the cells versus the reference, assigning those having a VT above the reference a first bit value, and the remaining cells a second bit value.