Blockchain Connection Apparatus Searchable Ciphertext Anonymity

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Solution Overview

Problem

Managing multiple key pairs for enhanced anonymity in blockchain transactions becomes complex and increases data management burdens for service providers in blockchain networks, particularly in systems like Bitcoin, where users need to conceal transaction sources and destinations.

Innovation Solution

A blockchain system uses a connection apparatus with an encryption processing unit that generates searchable ciphertext from keywords via a probabilistic encryption method, allowing multiple encrypted addresses to be generated from one keyword, simplifying address management while maintaining anonymity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple key pairs are generated for each transaction detail or purpose to enhance anonymity, then anonymity is improved, but management complexity and data amount increase

Engineering Contradiction:
ImproveanonymityVSAvoidmanagement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the key pair generation by creating multiple child key pairs from a single parent key pair. Each child key pair can be used for different transaction purposes while the parent key pair remains centralized for management. This segmentation allows anonymity to be improved through multiple key pairs while reducing management complexity by having a single parent key to safeguard.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by generating multiple child key pairs in advance from a parent key pair, before they are needed for transactions. The connection apparatus pre-generates and stores these child key pairs, so when a transaction needs to be anonymized, a suitable child key pair is already available without requiring on-demand generation or complex management during the transaction process.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If multiple key pairs are managed by service providers to enhance anonymity, then anonymity is improved, but data management burden increases

Engineering Contradiction:
ImproveanonymityVSAvoiddata amount
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments the key hierarchy into a parent key pair and multiple child key pairs. The service provider only needs to manage the single parent key pair data, while the child key pairs are derived computationally. This segmentation dramatically reduces the data amount the service provider must manage, as they store only the parent key pair rather than all individual child key pairs needed for anonymity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses copying in the form of cryptographic derivation, where child key pairs are generated as cryptographic copies of the parent key pair through a deterministic process. Instead of storing multiple independent key pair datasets, the service provider stores one parent key pair and can generate any needed child key pairs on-demand through cryptographic operations, significantly reducing storage requirements.

Inventive Principle:
Principle #26Copying

3Reliability

If traditional encryption methods are used for addresses, then anonymity is maintained, but searchability of transactions is reduced

Engineering Contradiction:
ImproveanonymityVSAvoidsearchability
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies local quality by making different parts of the address have different properties. The address is constructed with an encrypted portion (for anonymity) and an unencrypted hash portion (for searchability). This allows the address to simultaneously provide both anonymity through encryption and searchability through the hash component, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the address structure into multiple components: an encrypted address portion derived from the child key pair (providing anonymity) and a hash of the child key pair (providing searchability). This segmentation allows each component to serve its specific function, enabling both anonymity and searchability to coexist in the same address structure.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3531365B1Computer system, connection apparatus, and processing method using transaction
Publication Date: 2022.12.21 HITACHI LTD
  • EP3531365B1 patent drawingFigure 1
  • EP3531365B1 patent drawingFigure 2
  • EP3531365B1 patent drawingFigure 3

AI summary

A computer system includes a plurality of processing nodes constituting a blockchain network and a connection apparatus connecting to the blockchain network. The processing node holds information. The connection apparatus includes a connection processing unit that transmits a transaction to the processing node. The connection processing unit includes an encryption processing unit that generates searchable ciphertext from a keyword based on a probabilistic encryption method. The encryption processing unit generates, from the keyword, the searchable ciphertext to be used as an address indicating a transmission source or a transmission destination of the transaction, and generates the transaction including the searchable ciphertext.