Secret Multi-Iterative Computation With Early Inner-Loop Completion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods require executing inside iterative calculations MN times when an iterative calculation is further included, leading to excessive computational overhead.

Innovation Solution

A secure multi-iterative computation apparatus and method that initializes loop variables as dummy values, performs secure computations, and updates states to reduce unnecessary iterations by retaining loop variable values and continuing calculations only when inner iterations are complete.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an upper bound N is set for outside iterative calculation and an upper bound M is set for inside iterative calculation, then the inside iterative calculation must be executed MN-number of times, but this leads to excessive computational overhead and time consumption

Engineering Contradiction:
Improvesecurity of iterative calculationVSAvoidcomputational time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-establishing a mapping relationship between loop variables and iteration termination conditions before the iterative calculation begins. This allows the system to directly determine whether to terminate the inside iterative calculation based on the current loop variable value, without having to execute all MN iterations. The mapping relationship is created in advance, enabling efficient lookup during execution and significantly reducing computational time while maintaining security.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the number of iterations is limited to MN times, then the computational complexity is reduced, but the accuracy of the calculation result may be compromised when the actual required iterations exceed the limit

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidcalculation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the iteration termination condition adaptive rather than fixed. The system dynamically adjusts the termination of inside iterative calculations based on the current state of the outside iterative calculation and the pre-established mapping relationship. This allows the calculation to terminate early when appropriate, improving efficiency, while ensuring accuracy is maintained by only terminating when the mapping relationship confirms the condition is satisfied.

Inventive Principle:
Principle #15Dynamics

3Reliability

If dummy values are used for loop variables, then the security is improved by not revealing actual iteration counts, but the complexity of managing multiple states increases

Engineering Contradiction:
Improvesecurity against side channel attacksVSAvoidstate management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the intermediary principle by introducing a mapping relationship as a mediator between the loop variable and the iteration termination condition. This mapping relationship serves as an intermediate data structure that simplifies state management by providing a direct lookup mechanism. Instead of complex conditional logic to determine termination, the system uses the mapping relationship to efficiently determine whether to continue or terminate iterations, reducing the complexity of managing multiple states while maintaining security through dummy values.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4044156B1Secret multi-iterative calculation device, method, and program
Publication Date: 2025.07.09 NT T INC
  • EP4044156B1 patent drawingFigure 1
  • EP4044156B1 patent drawingFigure 2
  • EP4044156B1 patent drawingFigure 3

AI summary

When an inside iterative calculation does not end after a predetermined number of iterations, a midway value of a loop variable is retained and a calculation of an output value is not performed in an outside iterative calculation. In addition, subsequently, execution of the iterative calculation is continued using the value of the loop variable having been retained when the inside iterative calculation is executed once again. In other words, in each iterative calculation, an object iterative calculation is only performed when all iterative calculations immediately inside the object iterative calculation have ended. Recursively performing these processing steps enables wasteful calculation in inside iterative calculations to be reduced.