Multivariate Public Key Cryptosystem Security and Efficiency

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Solution Overview

Problem

Multivariate public key cryptosystems (MPKCs) face security and efficiency challenges, with existing designs being vulnerable to attacks and inefficient for practical applications, especially in small electronic devices like smartcards and RFID.

Innovation Solution

The introduction of 'internal perturbation plus' (IPP), 'enhanced internal perturbation' (EIP), and 'multi-layer Oil-Vinegar construction' (MOVC) methods to enhance the security and efficiency of MPKCs, making them more resistant to attacks and suitable for use in small devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing MPKC designs are used, then the system can provide basic cryptographic functionality, but the security is vulnerable to attacks and efficiency is insufficient for practical applications

Engineering Contradiction:
ImprovesecurityVSAvoidefficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the cryptographic system into multiple layers with different security requirements. The encryption layer uses fewer variables for efficiency, while the decryption layer uses more variables for security. This segmentation allows the system to achieve both high security and efficiency by assigning different functional requirements to different parts of the system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes key parameters of the MPKC system, specifically using a finite field with a larger number of elements (q > 2) and employing polynomial transformations with controlled degrees. These parameter changes improve both security resistance against known attacks and computational efficiency for practical applications.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If more variables are added to the polynomial equations to improve security, then the system becomes more resistant to attacks, but the computational complexity and processing time increase

Engineering Contradiction:
Improvesecurity resistanceVSAvoidcomputation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies local quality by having different numbers of variables in different parts of the system. The encryption function uses a smaller set of variables for fast computation, while the decryption function uses a larger set for security. This localized differentiation allows each part to optimize for its specific function without compromising the other.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces dynamic elements through the use of affine transformations and polynomial compositions that can be efficiently evaluated. The system dynamically balances security and efficiency by using structured polynomial forms that maintain security properties while enabling optimized computation through pre-computation and caching techniques.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the polynomial degree is increased to enhance security, then the system becomes more resistant to algebraic attacks, but the computational overhead and implementation complexity increase

Engineering Contradiction:
ImprovesecurityVSAvoidimplementation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-computing and storing certain polynomial transformations and their inverses. The system prepares lookup tables and pre-processed cryptographic materials during key generation, which reduces the complexity of real-time computations during encryption and decryption operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent substitutes complex mechanical polynomial inversion with more efficient computational methods. Instead of directly inverting high-degree polynomials, the system uses composed transformations of lower-degree polynomials that are easier to compute and invert, replacing the mechanical complexity with algorithmic efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS7961876B2Method to produce new multivariate public key cryptosystems
Publication Date: 2011.06.14 ALGO CONSULTING INC
  • US7961876B2 patent drawing
  • US7961876B2 patent drawing
  • US7961876B2 patent drawing

AI summary

Multivariate public key cryptosystems (MPKC) are public key cryptosystems, whose public key are a set of multivariate polynomials over a finite field (or ring). MPKC can be used for encryption, authentication and signatures. The invention develops three new methods that could be applied to a multivariate public key cryptosystem to produce new multivariate public key cryptosystems that are better in terms of security and efficiency. These three methods are called the internal perturbation plus (IPP), the enhanced internal perturbation (EIP) and the multi-layer Oil-Vinegar construction (MOVC). These three methods can be combined in any 2 or all 3 to be applied to a multivariate public key cryptosystem to produce new multivariate public key cryptosystems as well.