Cryptographic Parameter Setting via Random Divisor Selection

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Solution Overview

Problem

Cryptographic systems based on pairing operations over composite orders face inefficiencies due to large data sizes required for encryption, leading to prolonged operation times.

Innovation Solution

An encryption parameter setting apparatus and key generation apparatus that utilize random divisor selection, base divisor generation, discrete log calculation, and pairing log calculation to set encryption parameters and generate keys, leveraging cyclic groups and bilinear pairing operations to optimize cryptographic operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If pairing operation on composite order is used for cryptographic system, then sophisticated cryptography and signature can be realized, but data size becomes large and operation time becomes long

Engineering Contradiction:

Improvecryptographic functionalityVSAvoidoperation time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent changes the fundamental parameter of the cryptographic system by replacing composite order pairing operations with prime order pairing operations. This parameter change enables the system to achieve the same cryptographic functionality (adaptability) while significantly reducing the data size and operation time, as prime order fields require smaller representations and faster computations compared to composite order fields

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If pairing operation on composite order is used for cryptographic system, then sophisticated cryptography and signature can be realized, but data size becomes large

Engineering Contradiction:

Improvecryptographic functionalityVSAvoiddata size

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent changes the fundamental parameter of the cryptographic system by replacing composite order pairing operations with prime order pairing operations. This parameter change enables the system to achieve the same cryptographic functionality (adaptability) while significantly reducing the data size, as prime order fields require smaller representations and faster computations compared to composite order fields

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP2234322B1Cryptographic parameter setting device, cryptographic system, program, and cryptographic parameter setting method

Publication Date: 2019.10.02 MITSUBISHI ELECTRIC CORP

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AI summary

A sophisticated cryptographic system is realized without using a pairing operation on a composite order. A random matrix selection unit 142 randomly selects a random matrix V* from a plurality of matrices satisfying a predetermined condition, based on a plurality of pairing log coefficients ηi calculated by an encryption parameter setting apparatus 100. An output base calculation unit 143 calculates a plurality of output bases gk, based on a plurality of base divisors D∼j calculated by the encryption parameter setting apparatus 100 and the random matrix V* selected by the random matrix selection unit 142.