Inference Detection System for Document Privacy Protection

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Solution Overview

Problem

The challenge lies in detecting and preventing undesirable inferences from documents, especially when private information becomes partially public, allowing the public to infer sensitive details that were intended to remain private, due to the difficulty in concealing both direct and indirect clues in a vast and interconnected information environment like the Web.

Innovation Solution

A system that extracts relevant keywords from documents, formulates queries against a reference corpus, and identifies potential inferences by analyzing the intersection of knowledge from the documents and the reference corpus, using techniques like TF.IDF analysis and search query ratios to flag potentially dangerous inferences for manual review.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If information is made publicly accessible on the Web, then information availability and accessibility are improved, but information privacy protection deteriorates due to easy inference of sensitive details from disparate sources

Engineering Contradiction:
Improveinformation availabilityVSAvoidprivacy risk
Core Design Contradiction:
Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary inference detection before publishing documents. It extracts keywords from the document, formulates search queries, and checks if combinations of keywords can infer sensitive information from reference corpora, allowing preventive redaction before public release

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system introduces an intermediary inference detection mechanism between the document and the public. This intermediary analyzes potential inferences by searching reference corpora with keyword combinations, acting as a buffer to prevent harmful information leakage while maintaining public access

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If all information including indirect clues is concealed to protect privacy, then information privacy protection is improved, but information accessibility and usefulness deteriorate

Engineering Contradiction:
Improveprivacy protectionVSAvoidinformation accessibility
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The system applies selective redaction rather than blanket concealment. It analyzes each keyword combination locally to determine if it creates harmful inferences, redacting only specific sensitive information while leaving non-sensitive information accessible

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes the parameter of information disclosure from binary (all or nothing) to graded. It uses inference strength metrics to determine the level of redaction needed, allowing partial disclosure of information that does not create significant inference risks

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If comprehensive inference detection is performed by analyzing all possible keyword combinations against reference corpora, then inference detection accuracy is improved, but system complexity and computational cost increase

Engineering Contradiction:
Improveinference detection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs partial inference detection by focusing on the most likely inference paths. It uses techniques like TF.IDF to prioritize important keywords and limits analysis to top-k search results, achieving sufficient detection accuracy without exhaustive analysis of all possible combinations

Inventive Principle:
Principle #16Partial or excessive action

4Object-affected harmful factors

If extensive redaction is applied to prevent all possible inferences, then privacy protection is improved, but document quality and readability deteriorate

Engineering Contradiction:
Improveprivacy protectionVSAvoiddocument quality
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The system applies redaction locally only where inference risks are detected. It preserves the original document quality in non-sensitive areas while selectively redacting only the minimal necessary information that could lead to harmful inferences

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS7720783B2Method and system for detecting undesired inferences from documents
Publication Date: 2010.05.18 XEROX CORP
  • US7720783B2 patent drawing
  • US7720783B2 patent drawing
  • US7720783B2 patent drawing

AI summary

One embodiment of the present invention provides a system that detects inferences from documents. During operation, the system receives one or more documents and extracts a first set of knowledge relevant to the documents. The system further formulates one or more queries to one or more reference corpora based on the first set of knowledge. The system then extracts a second set of knowledge from results received in response to the queries. Additionally, the system produces a mapping relationship between at least one document and a piece of the second set of knowledge which is not within the first set of knowledge, the mapping relationship indicating an inference from the documents.