PUF-Based Secure Boot-Loading for Flash Data Recovery
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Solution Overview
Problem
High security devices with flash memory face data loss or corruption due to extreme environments, leading to a 'secured' state where data recovery is necessary to restore functionality, especially in high-cost electronic devices like smartphones and tablets, where ROM-based solutions are not flexible enough.
Innovation Solution
The integration of a Physical Unclonable Function (PUF) with secure flash memory devices provides a unique cryptographic key for data recovery, allowing the device to recover from data loss or corruption by using on-device secure boot-loading and PUF-based authentication with a server.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flash memory is used for software storage to provide flexibility and late software loading, then adaptability and ease of operation are improved, but reliability deteriorates due to data loss or corruption in extreme environments
Solution Approach 1:
A backup copy of the software is pre-stored on a secure server during device manufacturing. When data corruption is detected in flash memory, the device can automatically retrieve the backup software from the server to restore functionality, preventing complete device failure.
Solution Approach 2:
A secure server acts as an intermediary between the device and the software backup storage. The server stores encrypted backup copies of device software and provides them during recovery operations, enabling reliable data restoration without requiring direct device-to-device copying.
2Reliability
If data recovery mechanisms are implemented to restore functionality after data loss, then reliability is improved, but device complexity increases due to additional security mechanisms
Solution Approach 1:
The cryptographic key generation and storage functions are extracted from the device itself and relocated to a secure server environment. The device only retains the capability to request and receive encrypted backup data, significantly reducing the complexity of security mechanisms within the device while maintaining high reliability through server-based key management.
3Reliability
If ROM-based programming is used during silicon production to ensure high security, then reliability is improved, but adaptability deteriorates as software cannot be altered after production
Solution Approach 1:
The solution merges the security advantages of ROM-based programming with the flexibility of flash memory by combining on-device secure boot-loading capabilities with server-based backup storage. The device uses cryptographic authentication (similar to ROM security) to verify software integrity while allowing software to be updated and restored from external backup sources, achieving both security and adaptability.
Data Source
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AI summary
In high security devices, like smart cards, the on-board software may be embedded in ROM (read only memory). But, based on flexibility arguments, non-volatile flash memory-based software storage can be more preferred. This invention describes a method to recover from a situation of data loss on flash devices by combining the on-device available secure boot-loading with embedded physical unclonable functions (PUF), where the PUF provides the cryptographic key for starting the data recovery procedure.