Encrypted Trajectory Signature Vector for Privacy-Preserving Comparison
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Solution Overview
Problem
Existing methods for comparing geographical trajectories, such as those recorded by GPS navigation assistants, fail to protect user identity effectively, as anonymization techniques do not sufficiently obscure sensitive information that can reveal personal details like residence or age from the data.
Innovation Solution
A method involving the determination of a signature vector through the application of a hash function to an encrypted vector, which filters out irrelevant components and allows for efficient comparison of trajectories while maintaining user anonymity by only considering transitions between geographic cells, thereby reducing computational complexity and protecting user identity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trajectory data is anonymized to protect user identity, then user privacy is improved, but the ability to accurately compare trajectories and identify patterns is worsened
Solution Approach 1:
The patent introduces an intermediary mechanism (encrypted vector representation and signature computation) that allows trajectory comparison to be performed on encrypted data without decrypting it. This mediator enables pattern recognition while maintaining encryption, resolving the contradiction between privacy protection and comparison accuracy.
Solution Approach 2:
The patent transforms trajectory data from its original form into encrypted vector representations with specific mathematical properties. By changing the parameter representation (from raw coordinates to encrypted vectors with signature components), the system enables comparison operations on encrypted data, simultaneously achieving privacy protection and accurate pattern recognition.
2Measurement precision
If detailed trajectory data is retained for accurate comparison, then trajectory analysis precision is improved, but user identity protection is worsened
Solution Approach 1:
The encrypted vector signature acts as an intermediary that preserves the essential characteristics needed for trajectory comparison while preventing recovery of the original trajectory data. This intermediary structure allows precise pattern matching without exposing sensitive location information that could identify users.
Solution Approach 2:
The patent creates a cryptographic copy (encrypted vector representation) of the trajectory data that retains the necessary structural information for comparison operations. This copy enables accurate trajectory analysis while the original detailed data remains protected, as the encrypted representation cannot be reversed to reveal personal information.
3Loss of information
If all trajectory components are processed for comprehensive comparison, then comparison completeness is improved, but computational complexity is worsened
Solution Approach 1:
The patent extracts only the essential components needed for trajectory comparison by computing signatures from encrypted vectors. Instead of processing all trajectory data points, the system extracts signature components that capture the essential pattern information, reducing computational complexity while maintaining comparison completeness.
Solution Approach 2:
The patent replaces traditional mechanical comparison methods (which would require decrypting and processing all trajectory points) with a cryptographic substitution approach. By using signature computation on encrypted vectors, the system substitutes complex decryption and processing operations with more efficient cryptographic operations that achieve the same comparison goal with less computational burden.
Data Source
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AI summary
The invention relates to a method for comparing a first trajectory T with a second trajectory T', comprising: - determining a first signature vector, Sig(EV), determined by applying a hash function, f, to an encrypted vector, EV, being the result of the encryption of the vector V representing the trajectory T, - comparing Sig(EV) with a second signature vector Sig(EV'), the comparison comprising the application of a function D, the second signature vector Sig(EV') corresponding to the second trajectory T'.