Probabilistic Blockchain Transaction Filtering for Illicit Content

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Solution Overview

Problem

Existing blockchain systems lack effective methods to identify and prevent transactions associated with illicit activities or to ensure the legitimacy of transactions, making them susceptible to criminal use and compromising user security.

Innovation Solution

Implementing probabilistic filters, such as Bloom or Cuckoo filters, to encode whitelisted or blacklisted data items, allowing nodes to determine transaction processing based on membership tests, thereby preventing or allowing transactions based on predefined lists.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If blockchain nodes process all transactions without filtering, then transaction processing completeness is maintained, but security against illicit content deteriorates

Engineering Contradiction:
ImprovesecurityVSAvoidtransaction filtering mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary filtering of transactions before they are fully processed by blockchain nodes. Probabilistic filters are pre-computed and distributed to nodes, enabling them to quickly identify and reject transactions containing illicit content (such as illegal videos, images, or text) without performing complex analysis on every transaction, thus enhancing security while maintaining processing efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A probabilistic filter acts as an intermediary between the transaction pool and blockchain nodes. This filter encodes sets of illicit content identifiers and enables nodes to determine whether a transaction contains prohibited content through efficient membership tests, serving as a mediating layer that improves security without requiring nodes to directly analyze all transaction contents

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If probabilistic filters are used to filter transactions, then security against illicit content is improved, but processing speed deteriorates due to additional filtering steps

Engineering Contradiction:
ImprovesecurityVSAvoidtransaction processing speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system uses probabilistic filters that are computationally inexpensive and can be quickly updated or replaced. These filters are designed to be lightweight data structures that enable fast membership tests, allowing nodes to perform filtering operations with minimal computational overhead, thus maintaining high transaction processing speeds while improving security

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The system adjusts parameters of the probabilistic filter (such as false positive rate and filter size) to optimize the balance between security and processing speed. By tuning these parameters, the system can achieve high security coverage while minimizing the impact on transaction processing throughput, ensuring that the filtering mechanism does not become a bottleneck

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If comprehensive transaction filtering is implemented, then detection precision of illicit content is improved, but data storage requirements worsen

Engineering Contradiction:
Improvedetection precisionVSAvoiddata storage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system extracts only the essential identifying features of illicit content into the probabilistic filter, rather than storing complete copies of all illicit materials. The filter encodes hashed representations or key identifiers of prohibited content, enabling detection without requiring nodes to store large volumes of actual illicit data, thus achieving high detection precision with minimal storage requirements

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS20250240171A1Filtering blockchain transactions
Publication Date: 2025.07.24 NCHAIN LICENSING AG
  • US20250240171A1 patent drawing
  • US20250240171A1 patent drawing
  • US20250240171A1 patent drawing

AI summary

A computer-implemented method of processing a blockchain transaction, wherein the method is performed by a receiving party and comprises: obtaining one or more probabilistic filters, wherein each probabilistic filter encodes one of i) one or more sets of whitelisted data items, or ii) one or more sets of blacklisted data items; obtaining a blockchain transaction, wherein the obtained blockchain transaction is associated with a candidate data item corresponding to i) one of the one or more sets of whitelisted data items, or ii) one on the one or more sets of blacklisted data items; and determining whether to process the obtained blockchain transaction based on whether the candidate data item is present in at least one of the one or more probabilistic filters.