Geographical Track Data Obfuscation via Format-Preserving Encryption
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Solution Overview
Problem
Existing technologies face challenges in extracting non-sensitive metrics such as total distance, total time, and total elevation gain from encrypted geographical track data, which is essential for preserving user privacy while maintaining the ability to analyze and utilize this information.
Innovation Solution
The solution involves applying format-preserving encryption (FPE) to geographical data points, specifically encrypting delta degree values to obfuscate direction and time/elevation gains, allowing for the extraction of underlying metrics without decrypting the data, using a combination of first, second, and third FPE transformations to ensure data privacy and integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If geographical track data is encrypted to preserve user privacy, then user privacy is protected, but the ability to extract non-sensitive metrics such as total distance, total time, and total elevation gain is lost
Solution Approach 1:
The patent introduces encrypted differential values as an intermediary representation of geographical track data. Instead of encrypting the raw coordinate sequence directly, the system transforms coordinates into differential values (differences between consecutive points), then applies encryption. This intermediary representation allows metric extraction algorithms to operate on the encrypted data structure without needing to decrypt it, thereby preserving both privacy and analytical utility.
Solution Approach 2:
The patent changes the parameter representation of geographical data from absolute coordinates to differential values. By transforming the data from position-based parameters to difference-based parameters, the system enables metric extraction (distance, time, elevation) to be performed through operations on the encrypted differential values, maintaining the ability to compute aggregate metrics while preserving privacy.
2Reliability
If multiple FPE transformations are applied to encrypt delta degree values, then data privacy and integrity are enhanced, but the complexity of the encryption process increases
Solution Approach 1:
The patent segments the encryption process into three distinct FPE transformation stages applied sequentially to different aspects of the delta degree values. Each transformation layer addresses a specific security requirement, and the segmented structure allows for systematic implementation and verification of each encryption layer while maintaining overall system manageability.
Solution Approach 2:
The patent applies preliminary transformations to convert geographical coordinates into delta degree values before applying the main encryption transformations. This preliminary action prepares the data in a format that is more suitable for the subsequent FPE transformations, enabling the encryption process to operate on standardized differential representations rather than raw coordinate data.
Data Source
AI summary
In some examples, geographical track data obfuscation may include ascertaining geographical data points that include a first data point and subsequent data points. For each of the subsequent data points, a delta degree value may be determined as a difference between a subsequent data point and a corresponding previous data point. A first format preserving encryption (FPE) may be applied to encrypt longitude and latitude values of the first data point. A second FPE may be applied by applying a translation of a plurality of translations to encrypt each delta degree value. A total distance traveled, a total time, and/or a total elevation gain may be extracted from the encrypted first data point and the encrypted delta degree values.