Encrypted Set Intersection Vectors for Large PSI Computation

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Solution Overview

Problem

Existing private set intersection (PSI) techniques face challenges in performing operations for large data sets due to increased data transmission and computation amounts, leading to inefficiencies and slow computation speeds.

Innovation Solution

An apparatus and method that generate and manipulate ciphertext vectors corresponding to subsets of a universal set, allowing for set intersection operations to be performed in an encrypted state, using techniques like RSA and homomorphic encryption to determine intersections without exposing the underlying data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional PSI techniques (hash-based, public key cryptography-based, circuit-based, or oblivious transfer based) are used, then data privacy is protected, but data transmission amount and computation amount increase as comparison objects increase, making large data set operations impossible or too slow

Engineering Contradiction:
Improvedata privacy protectionVSAvoidcomputation speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments large data sets into multiple subsets and processes them in parallel using multiple processing circuits. Each circuit handles a portion of the data independently, reducing the computational burden on individual circuits and enabling scalable processing of large data sets while maintaining encryption-based privacy protection

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces conventional cryptographic mechanisms (hash-based PSI, public key cryptography-based PSI, circuit-based PSI, or oblivious transfer based PSI) with a homomorphic encryption-based system using polynomial representations and secret sharing. This substitution enables efficient computation on encrypted data without requiring complex cryptographic protocols, significantly improving computation speed while maintaining security

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conventional PSI techniques are used, then data privacy is protected, but data transmission amount increases as comparison objects increase

Engineering Contradiction:
Improvedata privacy protectionVSAvoiddata transmission amount
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments data into subsets processed in parallel, reducing the amount of data that needs to be transmitted between parties for any single processing operation. Each processing circuit receives only the subset of data it needs to process, thereby reducing overall transmission requirements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms data into polynomial representations and uses homomorphic encryption to perform operations on encrypted polynomials. This parameter transformation enables computation on encrypted data without requiring transmission of plaintext data, significantly reducing data transmission amounts while maintaining privacy

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If data sets are increased in size for PSI operations, then more comprehensive intersection analysis is achieved, but computation time increases making operations too slow

Engineering Contradiction:
Improvedata set sizeVSAvoidcomputation time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent divides large data sets into multiple subsets and processes them simultaneously using multiple processing circuits operating in parallel. This segmentation enables linear scalability where computation time increases proportionally with the number of processing circuits rather than quadratically with data set size, making large data set operations feasible

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary transformations of data into polynomial representations and establishes secret sharing schemes before the actual intersection computation. These preliminary actions organize data in a manner that enables efficient parallel processing and reduces the computational complexity of the main intersection operation

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3843319B1Apparatus and method for set intersection operation
Publication Date: 2025.12.03 SAMSUNG SDS CO LTD
  • EP3843319B1 patent drawingFigure 1~2
  • EP3843319B1 patent drawingFigure 3
  • EP3843319B1 patent drawingFigure 4

AI summary

An apparatus and method for set inspection operation are disclosed. The apparatus for set intersection operation according to an embodiment includes a ciphertext acquisition unit configured to acquire a ciphertext for a first vector corresponding to a first subset of a universal set including a plurality of elements from an encryption apparatus, a transform unit configured to generate a second vector corresponding to a second subset of the universal set, a computation unit configured to generate a ciphertext for a third vector corresponding to an intersection of the first subset and the second subset, based on the ciphertext for the first vector and the second vector, and a ciphertext providing unit configured to provides the ciphertext for the third vector to the encryption apparatus.