Loop Equalization in Arithmetic Logic Units for Cryptography

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Solution Overview

Problem

Existing cryptographic computing systems face inefficiencies in performing multiplication operations, particularly in modular arithmetic, which are crucial for public-key cryptography, due to the high computational cost of division operations and resource constraints on low-bit microprocessors.

Innovation Solution

The implementation of an efficient squaring algorithm with loop equalization, which optimizes the multiplication process by ensuring inner loops are of equal length, allowing for seamless integration with Montgomery reduction, thereby reducing the number of load operations and enhancing hardware efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional multiplication algorithms are used in cryptographic computing, then the multiplication operations can be performed, but the computational cost is high due to division operations and resource constraints on low-bit microprocessors

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidcomputational overhead
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent transforms the multiplication problem into a squaring problem by changing the parameter representation. By expressing the multiplier in a specific form and using the identity a×b = ((a+b)² - (a-b)²)/4, the algorithm converts general multiplication into repeated squaring operations, which are computationally cheaper and avoid expensive division operations required in conventional modular multiplication algorithms

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts and eliminates the expensive division operation from the computational process. By using Montgomery reduction and representing numbers in a specialized form, the algorithm removes the need for division operations entirely, replacing them with cheaper shift and add operations that are more efficient on resource-constrained devices

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If inner loops of unequal length are used in squaring algorithms, then the algorithm can be simpler to implement, but the integration with Montgomery reduction is not seamless and requires additional handling

Engineering Contradiction:
Improvealgorithm implementation simplicityVSAvoidintegration compatibility with Montgomery reduction
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent intentionally introduces asymmetry in the loop structure by padding shorter loops to match the length of the longest loop. This creates a uniform loop structure that enables seamless integration with Montgomery reduction, sacrificing some algorithmic simplicity for the benefit of hardware efficiency and integration compatibility

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent segments the squaring operation into multiple equal-length inner loops, each handling a specific portion of the computation. This segmentation allows each loop to be optimized independently and integrated systematically with Montgomery reduction steps, improving both implementability and hardware efficiency

Inventive Principle:
Principle #1Segmentation

3Productivity

If unequal length inner loops are used in squaring operations, then fewer load operations are required, but hardware efficiency is reduced

Engineering Contradiction:
Improvenumber of load operationsVSAvoidhardware efficiency
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent dynamically adjusts the loop structure to balance between the number of load operations and hardware efficiency. By making all inner loops equal in length, the algorithm creates a predictable, regular execution pattern that optimizes hardware resource utilization and enables better pipeline utilization in arithmetic logic units, while the overall efficiency is maintained through the mathematical optimizations in the squaring approach

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11961420B2Efficient squaring with loop equalization in arithmetic logic units
Publication Date: 2024.04.16 CRYPTOGRAPHY RESEARCH INC
  • US11961420B2 patent drawing
  • US11961420B2 patent drawing
  • US11961420B2 patent drawing

AI summary

Aspects of the present disclosure describe a method and a system to support execution of the method to perform a cryptographic operation involving identifying an N-word number, X=XN−1 . . . X1Xo, to be squared, performing a first loop comprising M first loop iterations, wherein M is a largest integer not exceeding (N+1)/2, each of the M first loop iterations comprising a second loop that comprises a plurality of second loop iterations, wherein an iteration m of the second loop that is within an iteration j of the first loop comprises computing a product Xa*Xb of a word Xa and a word Xb, wherein a+b=2j+m, j≥0 and m≥0, and wherein all second loops have an equal number of second loop iterations.