Secret String Calculation System Using Multi-Modulus Sharing
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Solution Overview
Problem
Existing MPC protocols are inefficient, particularly due to the high computational overhead associated with multiplication operations, which hinders effective retrieval of data from a database while maintaining privacy.
Innovation Solution
A secret character string calculation system that employs secret sharing with multiple moduli, utilizing the Chinese Remainder Theorem for efficient retrieval by minimizing multiplication through the use of the Carmichael function and modular exponentiation protocols, allowing servers to determine whether a registration character string matches a retrieval condition without revealing sensitive information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional MPC protocols are used for secure data retrieval, then privacy is maintained, but computational efficiency deteriorates due to high multiplication overhead
Solution Approach 1:
The patent segments the secret sharing scheme by using different moduli for different parts of the computation. Specifically, it divides the computation into segments that operate under different modular arithmetic systems, allowing multiplication operations to be replaced or simplified in certain segments while maintaining security through the overall secret sharing structure.
Solution Approach 2:
The patent changes the mathematical parameters of the MPC protocol by introducing specific modulus values and using the Carmichael function to transform the computational parameters. This parameter transformation allows the system to maintain the security properties of secret sharing while changing the operational characteristics to reduce multiplication overhead.
2Measurement precision
If multiplication operations are performed in MPC protocol, then accurate computation is achieved, but computational overhead increases significantly
Solution Approach 1:
The patent substitutes multiplication operations with modular exponentiation operations in the MPC protocol. By replacing the mechanical multiplication process with modular exponentiation using the Carmichael function, the system achieves comparable computational accuracy while significantly reducing the computational overhead associated with traditional multiplication in secret sharing schemes.
Data Source
AI summary
A registration apparatus generates shares by secret sharing of a character string with a plurality of modulus and sends the shares to a plurality of server apparatuses to be stored therein. A retrieval apparatus sends shares generated by secret sharing of a retrieval character string with the plurality of modulus to the plurality of server apparatuses. The plurality of server apparatuses execute a subroutine for shares of the each registration character string stored in a storage unit and for each of the plurality of modulus, reconstruct an execution result, and determine whether or not to return the shares of the registration character string stored in the storage unit as a retrieval result. A retrieval apparatus reconstructs shares returned from the plurality of server apparatuses and obtains a retrieval result in which the retrieval character string hits, from the reconstructed result by the Chinese remainder theorem.