Multivariate Polynomial Digital Signature Quantum Resistance

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Solution Overview

Problem

Current digital signature schemes and public-key authentication schemes rely on problems like prime factorization and discrete logarithm, which can be easily solved by quantum computers, compromising their security. There is a need for schemes based on different problems, such as multivariate polynomial problems, to ensure high security.

Innovation Solution

An information processing apparatus and method using a multi-order multivariate polynomial set and vector, where the polynomial set and vector are public keys, and a secret key is used to generate messages and responses for verification, ensuring security through the difficulty of solving multi-order multivariate simultaneous equations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If digital signature schemes based on prime factorization or discrete logarithm problems are used, then current security standards are met, but security is compromised when quantum computers are utilized

Engineering Contradiction:
ImprovesecurityVSAvoidresistance to quantum computer attacks
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the mathematical foundation from classical problems (prime factorization, discrete logarithm) to multivariate polynomial problems. Specifically, it uses a system of multivariate quadratic equations over finite fields, where the security relies on the difficulty of solving these equations without knowledge of the secret key structure, a problem that remains hard even for quantum computers.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If new digital signature schemes based on multivariate polynomial problems are implemented, then resistance to quantum computer attacks is achieved, but computational complexity increases

Engineering Contradiction:
ImprovesecurityVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the multivariate polynomial system into specific structured components: public matrices A and B, secret matrices S and T, and a structured polynomial system. This segmentation allows the complex problem to be divided into manageable parts where the public key consists of easily computable matrices while the security relies on the hidden structure of the secret matrices and their relationship through the polynomial equations.

Inventive Principle:
Principle #1Segmentation

3Reliability

If multi-order multivariate simultaneous equations are used for security, then quantum resistance is achieved, but solving difficulty increases even for classical computers

Engineering Contradiction:
ImprovesecurityVSAvoidease of solving
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent creates an asymmetric structure where the public key (matrices A and B) appears simple and easy to work with, while the secret key (matrices S and T with their specific structural relationships) provides the hardness. The asymmetry lies in the fact that while A and B are publicly available, deriving the secret structure from them requires solving the hard multivariate polynomial problem, creating a one-way function suitable for digital signatures.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentUS9490978B2Information processing apparatus and information processing method
Publication Date: 2016.11.08 SONY GROUP CORP
  • US9490978B2 patent drawing
  • US9490978B2 patent drawing
  • US9490978B2 patent drawing

AI summary

Provided is an information processing apparatus including a message generating unit that generates a message based on a multi-order multivariate polynomial set F=(f1, . . . , fm) defined on a ring K and a vector s that is an element of a set Kn, a message providing unit that provides the message to a verifier holding the multi-order multivariate polynomial set F and a vector y=(y1, . . . , ym)=(f1(s), . . . , fm(s)), and a response providing unit that provides the verifier with response information corresponding to a verification pattern selected by the verifier from among k (where k≧3) verification patterns. The vector s is a secret key. The multi-order multivariate polynomial set F and the vector y are public keys. The message is information obtained by performing an operation prepared for a verification pattern corresponding to the response information in advance using the public keys and the response information.