Security Controller Permutation for Side-Channel Attack Resistance
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Solution Overview
Problem
Existing cryptographic methods for processing data in security-relevant applications are inefficient against side-channel attacks due to high processing time and hardware requirements, and simpler methods are ineffective against dedicated attacks.
Innovation Solution
A security controller that processes data elements by determining a power of two number of data elements, using random integers to change indices through a sequence of permutations, including modular operations, to shuffle the processing order effectively while maintaining reasonable hardware requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex methods for generating uniformly distributed permutations are used to shuffle data processing order, then security against side-channel attacks is improved, but processing time and hardware requirements increase significantly
Solution Approach 1:
The permutation process is divided into multiple stages: selecting a base permutation from a limited set, applying modular multiplication, and performing modular addition. Each stage uses simple operations that can be efficiently implemented in hardware, avoiding the need for complex random permutation generation while maintaining security effectiveness.
Solution Approach 2:
The patent transforms the permutation generation problem by changing parameters from requiring full random permutations to using modular arithmetic operations with carefully selected parameters (modulus, multiplier, adder). This allows the use of pseudo-random parameters that provide sufficient security while being computationally efficient and hardware-friendly.
2Reliability
If complex permutation methods are used to protect cryptographic keys, then security is improved, but memory requirements and hardware complexity increase
Solution Approach 1:
The patent replaces complex mechanical/random permutation generation mechanisms with mathematical modular arithmetic operations. Instead of using hardware random number generators and complex permutation algorithms, the solution uses modular multiplication and addition with pseudo-random parameters, which can be implemented using simple arithmetic logic units already present in cryptographic processors.
3Productivity
If simple shuffling algorithms are used to reduce processing overhead, then processing efficiency is improved, but effectiveness against dedicated attacks decreases
Solution Approach 1:
The patent introduces dynamics by making the permutation parameters (modular multiplier and adder) variable and dependent on random values. This ensures that the permutation pattern changes with each cryptographic operation, preventing attackers from deducing patterns through multiple observations, while the underlying modular arithmetic operations remain computationally efficient.
Data Source
AI summary
According to an embodiment, a security controller is described comprising a memory storing data elements of a data array and a processing circuit configured to determine a power of two such that number of data elements is higher than the power of two but at most equal to double the power of two, determine random first and second integers, change indices of a predefined sequence of indices, comprising performing a first change of the index according to a first permutation if it is lower than the power of two, performing a second change of the index by adding a third integer modulo data array length and performing a third change of the index by a second permutation if it is, following the second change, lower than the power of two, and process the data elements in an order of the changed indices.