Secure Search Vector Decomposition for Multi-Result Encrypted Queries

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Solution Overview

Problem

Existing secure computation methods cannot compute confidential values of multiple pieces of data satisfying predetermined search conditions from a sequence of aligned data and a query.

Innovation Solution

A secure search system comprising three or more secure search devices that utilize vector decomposition, first and second detection means, and output computation to compute a share of a vector containing elements satisfying search conditions from aligned data and a query, using secure distribution methods for concealment, addition, subtraction, multiplication, division, and comparison operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If binary search is used in secure computation to find confidential values equal to or larger than a query, then the search can be performed on encrypted data, but only a single confidential value can be computed, not multiple values satisfying predetermined search conditions

Engineering Contradiction:
Improvesearch condition flexibilityVSAvoidnumber of results returned
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The invention divides the search process into multiple stages by segmenting the result vector into multiple sub-vectors. Each sub-vector corresponds to a specific range of sorted data, and the system iteratively searches through these segments to find all values satisfying the query condition. This segmentation enables the system to return multiple results while maintaining secure computation properties.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a one-dimensional binary search (returning a single value) to a multi-dimensional approach by creating a result vector with multiple elements, each representing a different segment of the sorted data. This dimensional expansion allows the system to simultaneously represent and process multiple potential results while maintaining encryption.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If encryption is applied to data and computation is performed on encrypted values, then data security is maintained, but the complexity of computation increases compared to plaintext processing

Engineering Contradiction:
Improvedata securityVSAvoidcomputation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by pre-sorting the encrypted data into a sorted order before the search operation. This pre-processing enables the use of efficient binary search algorithms on the encrypted data, reducing the computational complexity during the actual search phase while maintaining security.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention introduces an intermediary result vector that serves as a mediator between the encrypted data and the final search results. This intermediate structure allows the system to perform comparisons and selections on encrypted values without needing to decrypt them, thereby maintaining security while managing computation complexity through structured processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS20250348613A1Secure search system, secure search apparatus, secure search method, and program
Publication Date: 2025.11.13 NT T INC
  • US20250348613A1 patent drawing
  • US20250348613A1 patent drawing
  • US20250348613A1 patent drawing

AI summary

Provided is a technique for computing confidential values of a first plurality of pieces of data satisfying predetermined search conditions from a sequence of confidential values of N pieces of aligned data and confidential values of a query. A vector decomposition means for computing a share [[→vi]] of a vector →vi (i=1, . . . α) having a length β satisfying predetermined conditions from a share of an aligned vector →v having a length N, a first detection means for computing a share of a vector [[→f]] having a length α satisfying predetermined conditions from the share [[→vi]], a partial vector computation means for computing a share [[→a]] of a vector →a having a length βγ satisfying predetermined conditions using the share [[→vi]] and the share [[→f]], a second detection means for computing a share of [[→b]] a vector →b having a length β satisfying predetermined conditions from the share [[→a]], and an output computation means for computing a share of a search result vector from the share [[→a]] using the share [[→b]].