Homomorphic Encryption Re-Encryption via Key Management

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional homomorphic encryption requires frequent bootstrapping operations, leading to significant increases in execution time for analysis algorithms due to the inability to efficiently remove random values during homomorphic operations.

Innovation Solution

A method and apparatus that utilize a key management apparatus to re-encrypt ciphertexts based on determined count values, allowing for efficient re-encryption instead of bootstrapping, thereby reducing operation execution time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional homomorphic encryption is used, then encryption functionality is achieved, but execution time increases significantly due to frequent bootstrapping operations

Engineering Contradiction:

Improveencryption functionalityVSAvoidexecution time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent introduces a key management apparatus as an intermediary component that performs re-encryption operations. This mediator handles the complex task of managing encryption keys and performing re-encryption efficiently, separating this function from the main homomorphic computation and reducing the time overhead associated with frequent bootstrapping operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter approach by introducing count values that track the number of homomorphic operations performed on ciphertexts. Based on these count values, the system determines when re-encryption is needed, optimizing the balance between maintaining encryption security and minimizing the frequency of time-consuming bootstrapping operations.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If bootstrapping operation is performed frequently, then random value removal is achieved, but operation execution time increases significantly

Engineering Contradiction:

Improverandom value removalVSAvoidoperation execution speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-managing encryption keys and pre-determining when re-encryption is needed based on count values. This preparation allows the system to perform re-encryption operations more efficiently when needed, rather than performing unnecessary bootstrapping operations at every step, thus improving productivity while maintaining reliable random value removal.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from count values that track the number of homomorphic operations to determine when re-encryption is necessary. This feedback mechanism allows the system to adaptively manage re-encryption timing, avoiding excessive bootstrapping operations while ensuring random values are properly removed, thereby improving operation execution speed.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If homomorphic operation proceeds, then computation in encrypted state is achieved, but random value e becomes impossible to remove after certain point

Engineering Contradiction:

Improveencrypted state computationVSAvoidrandom value removal capability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The key management apparatus serves as an intermediary that manages the complex interaction between homomorphic operations and random value removal. It tracks operation counts and coordinates re-encryption timing to ensure that random values can be effectively managed and removed while maintaining the ability to perform computations in encrypted states.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical bootstrapping process with a more efficient re-encryption mechanism managed by the key management apparatus. This substitution uses cryptographic key management techniques to achieve random value removal without requiring frequent bootstrapping operations, thereby maintaining encrypted state computation capability while improving reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11277257B2Method and apparatus for performing operation using encrypted data

Publication Date: 2022.03.15 SAMSUNG SDS CO LTD

AI summary

A method for performing an operation according to one embodiment includes performing a homomorphic operation using one or more ciphertexts that are homomorphically encrypted based on an encryption key, determining a count value for a ciphertext generated through the homomorphic operation based on count values for each of the one or more ciphertexts, requesting a key management apparatus, which holds the encryption key and a decryption key corresponding to the encryption key, to re-encrypt the generated ciphertext based on the determined count value, acquiring, from the key management apparatus, a ciphertext generated by re-encrypting the generated ciphertext through decryption based on the decryption key and encryption based on the encryption key; and determining a count value for the acquired ciphertext to be a preset initial value.