Contact Tracing Using Ephemeral Identifiers for Privacy
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Solution Overview
Problem
Contact tracing during the COVID-19 pandemic is challenging due to asymptomatic individuals potentially infecting others before showing symptoms, making it difficult to identify infection clusters and exposed individuals.
Innovation Solution
A method involving endpoint devices that collect and anonymize interactions using ephemeral unique identifiers, which are precomputed based on secret keys and counters, allowing for anonymous and secure identification of contacts and exposure analysis without compromising user privacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact tracing is performed using traditional methods, then infection clusters can be identified, but user privacy is compromised and the system cannot effectively track asymptomatic carriers
Solution Approach 1:
The system segments the identification process into two independent components: ephemeral unique identifiers for anonymous interaction tracking and permanent unique identifiers for identity resolution. This segmentation allows contact tracing to proceed effectively while preserving user privacy, as the ephemeral identifiers can be collected and analyzed without exposing personal information until necessary for contact notification.
Solution Approach 2:
The patent introduces ephemeral unique identifiers as an intermediary mechanism between users and the contact tracing system. These temporary identifiers act as a mediator that enables interaction tracking without directly exposing user identities, thus maintaining privacy while allowing effective contact tracing and asymptomatic carrier detection.
2Measurement precision
If traditional contact tracing methods are used, then exposed individuals can be identified, but the system fails to account for asymptomatic carriers who show no symptoms
Solution Approach 1:
The system performs preliminary tracking of all interactions using ephemeral unique identifiers before any infection status is known. This preliminary action captures data from both symptomatic and asymptomatic carriers equally, allowing the system to later identify exposure clusters regardless of whether the infected individual shows symptoms, thereby improving detection accuracy and adaptability.
3Ease of operation
If permanent unique identifiers are used for contact tracing, then identity resolution is straightforward, but user privacy is compromised throughout the tracking process
Solution Approach 1:
The system segments the identifier system into ephemeral unique identifiers for anonymous tracking and permanent unique identifiers for identity resolution. This segmentation allows the system to maintain user privacy during the tracking process while still enabling straightforward identity resolution when needed for contact notification and exposure confirmation.
Solution Approach 2:
The system periodically resolves ephemeral unique identifiers to permanent unique identifiers at appropriate stages (such as when exposure is confirmed or contact notification is required). This periodic action maintains privacy during data collection while enabling identity resolution when necessary, balancing ease of operation with privacy protection.
Data Source
AI summary
A method may include collecting from each of multiple endpoint devices a set of anonymized interactions of the corresponding endpoint device with other endpoint devices. Each anonymized interaction in the set of anonymized interactions may be based on an ephemeral unique identifier of another endpoint device involved in a corresponding anonymized interaction with the corresponding endpoint device. The method may include, for each endpoint device, resolving identities of the other endpoint devices with which the corresponding endpoint device has interacted from the corresponding set of anonymized interactions.