Homomorphic Encryption for Secure Private Value Comparison

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing data encryption systems fail to efficiently and securely compare private values between two parties without revealing the values to each other, particularly in scenarios like Yao's millionaire problem, where high-performance computation with low error probability is required.

Innovation Solution

The implementation of a secure and efficient system using homomorphic encryption, specifically Paillier's encryption system, allows for a greater-than comparison of private values by encrypting and decrypting values using public and private keys, ensuring security and reliability while minimizing data exchange and computational errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional encryption systems are used to compare private values, then security is maintained, but computational efficiency deteriorates and error probability increases

Engineering Contradiction:

Improvecomparison accuracyVSAvoidcomputation speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces traditional mechanical computation methods with homomorphic encryption operations. Specifically, it uses Paillier encryption to perform comparisons through cryptographic operations (modular exponentiation and multiplication) rather than direct computational comparison, achieving both security and efficiency simultaneously

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the parameter representation by working with encrypted values instead of plain values. It transforms the comparison problem into a cryptographic parameter manipulation problem where comparisons are performed on ciphertexts, eliminating the need for decryption and re-encryption operations

Inventive Principle:

Principle #35Parameter changes

2Reliability

If variants of Fischlin's solution are used to reduce error probability, then reliability improves, but computational effort increases

Engineering Contradiction:

Improveerror probabilityVSAvoidcomputational effort

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses cryptographic copying where the encrypted value serves as a copy that preserves all necessary information for comparison without revealing the original value. The homomorphic properties allow operations on the encrypted copy to yield correct comparison results, eliminating the need for multiple computational variants to reduce errors

Inventive Principle:

Principle #26Copying

3Productivity

If direct comparison methods are used, then computational efficiency improves, but security deteriorates as private values are revealed

Engineering Contradiction:

Improvecomputation speedVSAvoidprivacy leakage

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent introduces homomorphic encryption as an intermediary that enables comparison operations without direct access to private values. The encryption scheme acts as a mediator that preserves the comparison functionality while maintaining security, allowing computations on encrypted data to produce correct results without revealing underlying values

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8045711B2System and method for comparison of private values

Publication Date: 2011.10.25 UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR NAT AERONAUTICS & SPACE ADMINISTRATION

AI summary

An embodiment includes a first system for computing a contribution to a greater-than comparison of a first private value and a second private value. The first system includes: an accessing unit configured to access the first private value; a processor unit configured to compute a first encrypted value by encrypting the first private value, compute a decrypted value by decrypting a third encrypted value, and compute a contribution to a result of the greater-than comparison by checking a relation between the decrypted value and a modulus value; and a communication unit configured to send the first encrypted value to a second system and to receive the third encrypted value.