Address Dependent Data Encryption Using PUF Circuitry
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Solution Overview
Problem
Data processing systems face challenges in securely erasing data from memory due to data remanence and energy consumption issues with existing encryption mechanisms, particularly in battery-operated IoT devices where complex algorithms like RSA consume significant energy for encryption and decryption.
Innovation Solution
The proposed solution involves using memory with physically unclonable function (PUF) circuitry to generate keys based on addresses for encrypting and decrypting data using one-time-pad encryption, which provides secure and low-energy operations by varying keys for different addresses and devices, and employing symmetric encryption for efficient data protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex encryption algorithms like RSA are used to protect data, then security is improved, but energy consumption increases significantly
Solution Approach 1:
The encryption process is segmented into two distinct phases: key generation using PUF circuitry (which occurs once during device initialization) and data encryption/decryption using symmetric keys (which occurs during data operations). This segmentation allows the energy-intensive asymmetric key generation to happen only once, while subsequent operations use energy-efficient symmetric encryption.
Solution Approach 2:
The PUF-based key generation is performed as a preliminary action during device initialization or first use. The generated symmetric keys are then cached and reused for multiple encryption/decryption operations, eliminating the need to repeatedly perform energy-intensive key generation during normal data operations.
2Loss of information
If data is erased from volatile memory by removing power, then data is assumed to be unrecoverable, but data remanence allows reconstruction of erased data
Solution Approach 1:
Different encryption keys are used for different memory addresses or address ranges. This local quality approach ensures that even if data remanence allows reconstruction of encrypted data at one address, the attacker cannot decrypt it without the specific key associated with that address, which is derived from the PUF and the address itself.
Solution Approach 2:
The encryption key is changed based on the memory address parameter. Each memory location is encrypted with a unique key derived from the combination of the PUF output and the address, so that erased data at different addresses produces different remanent patterns that cannot be decrypted without the corresponding address-specific key.
3Productivity
If the same data is written to different memory addresses, then storage efficiency is improved, but security is reduced because identical data patterns become identifiable
Solution Approach 1:
Each memory address has its own unique encryption key derived from the PUF and the address. This means that even when the same plaintext data is stored at different addresses, the ciphertext will be different because each location uses a different key, thereby maintaining security while allowing storage efficiency.
Data Source
AI summary
Encryption of data within a memory 6 is provided by key generation circuitry 12 which serves to generate a key as a function of the address within the memory 6 being accessed and then encryption circuitry 14 or decryption circuitry 16 which serve respectively to encrypt or decrypt the data as a function of the key that has been generated based upon the address. The encryption and the decryption may be performed using a bitwise XOR operation. The key generation circuitry may have the form of physically unclonable function circuitry, which varies from instance to instance of implementation and that operates to generate the same key for the same address upon both write and read operations within the same instance.