Array Copy Permutation to Obscure Cryptographic Power Signatures
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Solution Overview
Problem
Side-channel attacks can reconstruct and evaluate correlations in cryptographic operations by analyzing power consumption and electromagnetic radiation, compromising the security of cryptographic implementations, even in secure mathematical models.
Innovation Solution
A method involving the permutation of elements in source and target arrays during copying, using random or pseudorandom permutations to obscure the sequence of memory accesses, thereby reducing statistical correlations between spatial and temporal signatures of power profiles, making it difficult for attackers to deduce the copied data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data words are transmitted in a randomly permutated sequence during memory copying, then protection against side-channel attacks is improved, but characteristic power signatures and spatial localization of memory accesses can still be detected
Solution Approach 1:
The patent applies dynamics by making the memory access pattern change over time through iterative permutations. After each copying step, the source and/or target arrays are permuted again, creating a dynamically changing access pattern that prevents attackers from establishing stable correlations between power consumption and data values.
Solution Approach 2:
The patent implements periodic action by repeatedly applying permutations at regular intervals (after each copying step). This periodic re-shuffling of data positions creates a rhythm of change that disrupts the ability of side-channel attackers to accumulate meaningful statistical data across multiple operations.
2Reliability
If memory accesses are randomized during copying, then statistical correlations are reduced, but read or write accesses to specific data words can still have characteristic power signatures
Solution Approach 1:
The patent applies preliminary action by performing a permutation of the source and/or target arrays before each copying step. This pre-shuffling ensures that even before the actual copying begins, the data is already in a randomized position, preventing attackers from predicting or correlating power consumption with specific data values.
Solution Approach 2:
The dynamic re-permution after each copying step ensures that the memory access pattern never repeats the same sequence twice, making it impossible for attackers to establish consistent power signatures for specific data words across multiple operations.
3Reliability
If elements are copied in a permuted sequence, then correlations between measured quantities and cryptographic results are obscured, but the copying process requires multiple steps increasing operation time
Solution Approach 1:
The patent applies segmentation by dividing the copying operation into multiple small steps, where each step copies only a portion of the data (e.g., one word at a time) followed by a permutation. This segmentation breaks down what would otherwise be a single long operation into many short operations, each with its own randomized access pattern, providing security while managing time through efficient small-step execution.
Data Source
AI summary
A method is proposed for copying a source array into a target array, wherein both the source array and the target array have at least two elements, wherein each element has a value, in which the elements of the source array are copied into the target array in the sequence of a random permutation, wherein, after a step of copying an element of the source array into the target array, the source array, the target array or the source array and the target array are rotated. A device is also indicated accordingly.