Secret Sharing Fragment Replacement for Secure Computation

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Solution Overview

Problem

Conventional secure computation techniques fail to randomly replace multiple data pieces while concealing the association between them, leading to potential leakage of information.

Innovation Solution

A secret sharing system with N secret sharing apparatuses, employing selection, fragment replacement, and reshare mechanisms to generate bijections and replace fragments, ensuring that unselected apparatuses remain unaware of the association between numeric values, allowing for secure computation and sorting algorithms like quicksort without increasing the number of comparisons.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional secure computation techniques are used, then calculation results can be obtained without reconstructing encrypted numeric values, but multiple pieces of data cannot be randomly replaced while concealing the association between the pieces of data

Engineering Contradiction:
Improvesecurity of computationVSAvoidability to randomly replace data
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent divides secret sharing apparatuses into selected and unselected groups, with selected apparatuses performing fragment replacement operations while unselected apparatuses maintain original data associations. This segmentation allows the system to achieve both security (through distributed secret sharing) and adaptability (through selective random replacement by chosen apparatuses).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Selected secret sharing apparatuses act as intermediaries that perform the fragment replacement operation. These intermediary apparatuses enable random replacement of data fragments while the unselected apparatuses remain unaware of the association changes, thus concealing the transformation from the broader system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If fragment replacement is performed to conceal data association, then security is improved, but the system complexity increases due to selection mechanisms and bijection generation

Engineering Contradiction:
Improveconcealment of data associationVSAvoidselection and reshare mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into the secret sharing apparatuses: they simultaneously perform secret sharing, selection based on identifiers, fragment replacement with bijections, and reshare operations. This merging reduces overall system complexity by consolidating what could be separate components into integrated apparatuses that handle multiple tasks.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The secret sharing apparatuses autonomously perform selection of other apparatuses based on their identifiers, generate necessary bijections, and execute fragment replacements without requiring external coordination. This self-service capability reduces control overhead and simplifies the system architecture.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If all apparatuses know the association between numeric values, then computation is simpler, but information security is compromised

Engineering Contradiction:
Improvecomputation simplicityVSAvoidleakage of data association
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent implements local quality by giving different knowledge states to different apparatuses: selected apparatuses possess knowledge of the bijection and can perform fragment replacement, while unselected apparatuses maintain ignorance of the association. This localized knowledge distribution enables computation to proceed securely without requiring all apparatuses to have complete information.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2608190B1Secret sharing system, secret sharing apparatus, secret sharing method, secret sorting method and secret sharing program
Publication Date: 2016.05.11 NIPPON TELEGRAPH & TELEPHONE CORP
  • EP2608190B1 patent drawingFigure 1
  • EP2608190B1 patent drawingFigure 2
  • EP2608190B1 patent drawingFigure 3~4

AI summary

A secret sharing system according to the present invention includes N secret sharing apparatuses. The secret sharing system according to the present invention includes fragment replacement means and reshare means. The fragment replacement means selects a number, smaller than N, of secret sharing apparatuses, generates a bijection π of {1, ..., K} → {1, ..., K} among the selected secret sharing apparatuses and designates a fragment aπ(k)i recorded in a selected secret sharing apparatus as a k-th fragment (i represents an identification number that indicates a selected secret sharing apparatus). The reshare means performs reshare of fragments of a numeric value used as replacements by the fragment replacement means to determine new fragments.