vDGHV Key Generation Using Hard-to-Factor Primes

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Solution Overview

Problem

The existing vDGHV key generation method for fully homomorphic public-key encryption is vulnerable to security flaws due to the possibility of factoring the secret key, allowing attackers to decompose the prime factors and compromise the key's security.

Innovation Solution

Generating a secret key SK corresponding to a random prime number or a product of prime numbers that is difficult to factor, making it unachievable for attackers to compute the key, thereby enhancing the security of the key generation process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a random number p is used as the secret key in the vDGHV key generation method, then the key generation process is simple and efficient, but the security is compromised because the random number can be factored into prime factors

Engineering Contradiction:
Improvekey generation efficiencyVSAvoidkey security
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the parameter type of the secret key from a general random number to a specifically constructed number with difficult-to-factor properties. This is achieved by selecting prime numbers p such that p-1 has a large prime factor, making the discrete logarithm problem hard and preventing efficient factoring attacks on the public key components.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the secret key p is made difficult to factor by using specific prime number properties, then the security is enhanced, but the key generation process becomes more complex

Engineering Contradiction:
Improvekey securityVSAvoidkey generation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-selecting prime numbers with specific properties (where p-1 has a large prime factor) before the actual key generation process. This preliminary selection ensures that subsequent key generation operations remain efficient while maintaining high security, as the difficult-to-factor property is established in advance through careful prime number selection.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS9338000B2Device and method for generating keys with enhanced security for fully homomorphic encryption algorithm
Publication Date: 2016.05.10 BANKS & ACQUIRERS INT HLDG SAS
  • US9338000B2 patent drawing
  • US9338000B2 patent drawing
  • US9338000B2 patent drawing

AI summary

There is proposed a method of generating secret and public keys vDGHV with enhanced security, implemented in a device including at least one microprocessor and a memory. The method includes generating a secret key SK corresponding the generation of a prime random number p or product of prime numbers.