SPI Flash Replay Protected Monotonic Counter Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Standard SPI flash memory devices lack mechanisms to protect monotonic counter values from replay attacks, which compromises device security, and existing solutions either incur high costs or rely on volatile memory that loses data upon power removal.
Innovation Solution
Implementing a replay protected monotonic counter storage mechanism in SPI flash memory devices using flash memory controllers, unique device keys, and Hash-based Message Authentication Code (HMAC) key logic, which authenticates commands and generates responses to ensure secure storage and retrieval of monotonic counter values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard SPI flash memory devices are used for storing monotonic counters, then cost is reduced and ease of manufacture is improved, but security against replay attacks deteriorates
Solution Approach 1:
The patent segments the flash memory into multiple regions including a first region for monotonic counter data and a second region for authentication data. This segmentation allows standard flash memory to provide both storage functionality and security capabilities by separating counter values from their authentication mechanisms, resolving the contradiction between using standard memory and ensuring security.
Solution Approach 2:
The patent introduces authentication data as an intermediary element that mediates between the stored counter values and the security verification process. This authentication data acts as a mediator that enables standard flash memory to provide replay protection without requiring specialized secure memory hardware.
2Reliability
If on-chip SRAM is used for monotonic counter storage, then replay protection is achieved, but power consumption increases and data loss occurs upon power removal
Solution Approach 1:
The patent uses standard flash memory which can be repeatedly programmed and erased, replacing the need for expensive always-powered SRAM. The flash memory serves as a disposable-like storage medium that maintains data without power, achieving replay protection without continuous power consumption.
Solution Approach 2:
The patent changes the storage medium parameter from volatile SRAM to non-volatile flash memory, fundamentally altering the power consumption characteristic while maintaining replay protection through the authentication mechanism embedded in the flash memory structure.
3Reliability
If eMMC devices are used for replay protected storage, then security is improved, but cost and device complexity increase significantly
Solution Approach 1:
The patent merges the monotonic counter storage and authentication functions into a single flash memory device, eliminating the need for separate secure storage hardware like eMMC. This consolidation reduces device complexity while maintaining replay protection through the integrated authentication data structure.
Solution Approach 2:
The patent makes standard flash memory multi-functional by enabling it to store both monotonic counter values and authentication data, allowing a single inexpensive component to perform both storage and security verification functions that previously required specialized hardware.
4Reliability
If authentication mechanisms are added to SPI flash memory, then security is improved, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-generating authentication data during manufacturing and programming it into the flash memory alongside the initial counter values. This preliminary setup enables security verification to be performed using standard manufacturing processes without requiring complex post-manufacturing assembly or specialized secure elements.
Data Source
AI summary
Embodiments of the invention create an underlying infrastructure in a flash memory device (e.g., a serial peripheral interface (SPI) flash memory device) such that it may be protected against user attacks—e.g., replacing the SPI flash memory device or a man-in-the-middle (MITM) attack to modify the SPI flash memory contents on the fly. In the prior art, monotonic counters cannot be stored in SPI flash memory devices because said devices do not provide replay protection for the counters. A user may also remove the flash memory device and reprogram it. Host platforms alone cannot protect against such hardware attacks.Embodiments of the invention enable secure standard storage flash memory devices such as SPI flash memory devices to achieve replay protection for securely stored data. Embodiments of the invention utilize flash memory controllers, flash memory devices, unique device keys and HMAC key logic to create secure execution environments for various components.