Domain-Based Homomorphic Key Management for Ciphertext Reuse

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Solution Overview

Problem

Existing communication networks face challenges in efficiently managing homomorphic task keys to support end-to-end data privacy and security while facilitating homomorphic computations across various domains, particularly in the context of emerging technologies like immersive extended reality (XR), digital twins, and meta universe, where data privacy and security requirements are stringent.

Innovation Solution

A domain-based key management method and apparatus that decouples homomorphic encryption keys from user status and tasks, enabling reuse of homomorphic ciphertext across different tasks and reducing key complexity by managing keys at the domain level, thereby improving computation efficiency and reducing overheads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If user-level homomorphic encryption keys are used (each homomorphic encryption party corresponds to one homomorphic encryption key), then user-specific security is improved, but the quantity of homomorphic encryption keys increases, leading to increased derivation of homomorphic computation keys and reduced computation efficiency

Engineering Contradiction:
Improveuser-specific securityVSAvoidhomomorphic computation efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the key management system into domain-level keys and user-level keys. Domain-level homomorphic encryption keys are shared among multiple users within the same domain, while user-specific security is maintained through domain-specific key derivation. This segmentation reduces the total number of keys needed while preserving security boundaries between domains.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements universality by allowing a single domain-level homomorphic encryption key to serve multiple users within the same domain. The domain-level key can be reused across different homomorphic tasks and by multiple homomorphic encryption parties, eliminating the need for separate user-specific keys while maintaining security through domain isolation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If domain-level homomorphic encryption keys are used, then the quantity of homomorphic encryption keys is reduced and computation efficiency is improved, but key management complexity across domains increases

Engineering Contradiction:
Improvehomomorphic computation efficiencyVSAvoidkey management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces a domain dimension to the key management hierarchy. Instead of flat user-level keys, the system organizes keys in a hierarchical structure with domain-level keys at one level and user-specific derivations at another. This dimensional organization simplifies management by grouping users into domains with shared keys, reducing overall key management complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If homomorphic encryption keys are decoupled from user status and specific homomorphic tasks, then reusability of homomorphic ciphertext is improved, but adaptability to different user contexts is reduced

Engineering Contradiction:
Improvereusability of homomorphic ciphertextVSAvoidadaptability to different user contexts
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by making homomorphic encryption keys domain-specific rather than user-specific. Each domain has its own homomorphic encryption key that is optimized for that domain's specific requirements and data characteristics. This allows ciphertext to be reused within the same domain while maintaining appropriate security and adaptability for that local context.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4704361A1Region-based management method and apparatus for keys
Publication Date: 2026.03.04 HUAWEI TECH CO LTD
  • EP4704361A1 patent drawingFigure 1A~1C
  • EP4704361A1 patent drawingFigure 1D
  • EP4704361A1 patent drawingFigure 2

AI summary

This application relates to the field of communication technologies, and in particular, to a domain-based key management method and an apparatus, to manage, within a communication network, a homomorphic task key, and support application of a homomorphic task to the communication network. The method includes: A first control network element obtains a first homomorphic encryption key corresponding to a first domain; the first control network element sends the first homomorphic encryption key to M first homomorphic enabling units belonging to the first domain, where M is an integer greater than or equal to 1; and the first control network element sends a first homomorphic computation key to N second homomorphic enabling units belonging to the first domain, where N is an integer greater than or equal to 1, and the first homomorphic computation key is determined based on the first homomorphic encryption key and/or a first homomorphic decryption key corresponding to the first homomorphic encryption key.