Secret Calculation System Using Multi-Key Encrypted Data Processing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing secret calculation systems face a security issue due to shared secret keys, allowing aggregation terminals to decrypt encrypted data.

Innovation Solution

A secret calculation system that acquires and processes encrypted data using different key information from multiple information processing systems, performing calculations in an encrypted state to generate result data without decrypting the input data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a shared secret key is used for encryption between data providing terminal and aggregation terminal, then the aggregation terminal can decrypt the encrypted data for processing, but the security of the encrypted data is compromised

Engineering Contradiction:

Improveability to decrypt and process dataVSAvoidsecurity of encrypted data

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The secret key is segmented into multiple key shares distributed among different terminals. No single terminal possesses the complete key, preventing unauthorized decryption while enabling collaborative processing through secure multi-party computation protocols.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A trusted third-party server acts as an intermediary to manage key distribution and coordinate secret computation. The server facilitates data processing without having access to the complete secret key, maintaining security while enabling computation on encrypted data.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If encrypted data is processed without decryption, then data security is maintained, but the ability to perform calculations on the data is limited

Engineering Contradiction:

Improveconfidentiality of dataVSAvoidability to perform calculations

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system transforms the computational parameters and data representation into forms that allow mathematical operations to be performed directly on encrypted values. Homomorphic encryption properties enable addition and multiplication operations on ciphertexts, producing encrypted results without decryption.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Traditional decryption-based processing is replaced with homomorphic encryption-based computation. Instead of decrypting data to perform operations and then re-encrypting, the system performs operations directly on encrypted data through specialized cryptographic protocols.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12341877B2Secret calculation system, secret calculation method, and secret calculation program

Publication Date: 2025.06.24 NOMURA RESEARCH INSTITUTE

AI summary

A secret calculation system includes an acquisition unit that acquires each of a plurality of pieces of processing target data indicating data encrypted using a plurality of pieces of different key information generated by a plurality of information processing systems, from a corresponding information terminal of a plurality of information terminals, a secret calculation unit that generates result data indicating a result of calculation based on the plurality of pieces of processing target data in a state where the plurality of pieces of processing target data are encrypted, and a providing unit that provides the result data to the plurality of information terminals.