Secret calculation device, secret calculation method and secret calculation program

The improved CMux Tree structure for TFHE efficiently evaluates n-bit discrete functions by optimizing CMux gate executions based on binary patterns, addressing the inefficiencies of existing methods and achieving reduced computational complexity.

JP2025042949AActive Publication Date: 2025-03-28KDDI CORP
2 Cites 0 Cited by

Patent Information

Application Number
JP2023150169
Authority / Receiving Office
JP · JP
Patent Type
Applications
Current Assignee / Owner
Filing Date
2023-09-15
Publication Date
2025-03-28
Estimated Expiration
2043-09-15

AI Technical Summary

Technical Problem

Existing methods for evaluating n-bit discrete functions on Fully Homomorphic Encryption (FHE) suffer from high spatial complexity and require exponential time, making them inefficient for practical applications.

Method used

The proposed solution involves an improved CMux Tree structure for evaluating discrete functions on TFHE, where the setting unit sets appropriate ciphertexts for the deepest CMux gate, and the operation execution unit executes only the CMux gates above the deepest gate, optimizing the number of executions based on binary patterns in the lookup table.

Benefits of technology

This approach significantly reduces the number of CMux gate executions, from 2^n-1 to 2^n-1 reduced to 2^n-1 times, thereby enhancing the efficiency of evaluating n-bit discrete functions on TFHE, achieving a more efficient computational complexity.

✦ Generated by Eureka AI based on patent content.
Patent Text Reader

Abstract

To provide a secret calculation device capable of efficiently evaluating an arbitrary n-bit discrete function on TFHE, a secret calculation method and a secret calculation program.SOLUTION: A secret calculation device 1 includes: a setting unit 11 which, in CMux Tree for evaluating a discreet function on TFHE, sets an encrypted text of any one of a constant number 0 or 1, or a constant number x corresponding to a selector x or 1-x, in place of CMux gate in the deepest part, with respect to four types of patterns of binary character strings of a look-up table corresponding to the CMux gate in the deepest part; and a calculation execution unit 12 for executing only the CMux gate in the upper rank than the CMux gate in the deepest part.SELECTED DRAWING: Figure 1
Need to check novelty before this filing date? Find Prior Art