Differential Privacy to the Rescue? On Obfuscating Tolls in Privacy-Preserving ETC Systems
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Tagung:
Differential Privacy to the Rescue? On Obfuscating Tolls in Privacy-Preserving ETC Systems
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Tagungsort:
252 / BBB
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Datum:
2025-10-14
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Zeit:
15:45
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Electronic toll collection (ETC) systems are becoming increasingly popular, but are inherently privacy-sensitive as they deal with users’ location data. To this end, quite some research effort has been put into the design of privacy-preserving ETC (PPETC) systems. In this paper, we study the actual privacy properties of PPETC schemes, which hide the individual toll fees from the toll service provider and provide it only with a total monthly fee. Since previous work has shown that PPETC schemes may not suffice to protect the privacy of users in real scenarios, we analyze the effectiveness of using an additional protection mechanism: applying a differential privacy mechanism that hides the actual monthly toll fee by adding a small amount of noise. While this seems like a straightforward solution, it is not that simple: Since adding noise to monthly fees can increase monetary costs for users, the added noise should be kept small. But since adding more noise intuitively means more privacy when applying differential privacy, one must carefully choose the amount of added noise in order to strike a balance between privacy gain and additional cost.