Encryption Engine Randomized Round Scheduling Side Channel
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Solution Overview
Problem
Battery-powered artificial reality systems, such as head-mounted displays, are vulnerable to side-channel attacks due to their low-power designs and portable nature, which makes them susceptible to unauthorized access through the exploitation of hardware performance information.
Innovation Solution
The implementation of data-shuffling techniques in decryption engines that randomly permute data segments during the decryption process, obfuscating power consumption information and thwarting side-channel attacks while maintaining standard-compliant data output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low-power design is used in battery-powered artificial reality systems, then energy consumption is reduced and portability is improved, but vulnerability to side-channel attacks increases
Solution Approach 1:
The patent applies dynamics by making the decryption process adaptive through randomized round scheduling. The decryption engine dynamically selects different execution orders for decryption rounds based on randomized patterns, causing the power consumption profile to vary across different decryption operations. This dynamic behavior prevents attackers from correlating consistent power traces with specific key operations, thereby maintaining security while preserving low-power design benefits.
Solution Approach 2:
The patent changes the parameter of execution order (scheduling sequence) of decryption rounds. By randomizing the order in which decryption rounds are executed and introducing variable delays between operations, the power consumption parameters become unpredictable. This parameter change obscures the relationship between power consumption and cryptographic operations, protecting against side-channel attacks without requiring additional hardware power.
2Reliability
If data shuffling techniques are implemented in decryption engines, then resistance to side-channel attacks is improved, but device complexity increases
Solution Approach 1:
The patent segments the decryption process into multiple independent rounds that can be executed in randomized orders. Each decryption round is treated as an independent segment with standardized functionality. This segmentation allows the use of simple, reusable decryption round modules while achieving complex security properties through varied composition and scheduling of these segments, thereby limiting the increase in device complexity.
3Reliability
If randomized round scheduling is used, then power consumption information is obfuscated, but decryption processing time increases
Solution Approach 1:
The patent employs periodic action by introducing regular, randomized delays between decryption rounds. Instead of continuous processing, the decryption engine executes rounds with periodic interruptions that follow randomized patterns. This periodic structure with variable intervals obfuscates the timing and power consumption information related to specific cryptographic operations, while the overall processing time increase remains controlled and acceptable for security-critical applications.
Data Source
AI summary
Encryption engines shuffle data segments during encryption and/or decryption, thereby obtaining a random permutation of the data segments to be used during encryption and/or decryption. By shuffling the data during encryption/decryption and using the resulting random permutation for encryption/decryption, the encryption engines obfuscate the power consumption information that attackers might access as part of an SCA. In some examples, the encryption engines perform intra-round shuffling of the input data within a reduced-sized encryption datapath configured to iteratively compute a portion of an encrypted block of data.