Wearable Contact Tracing Hashes for Opt-In Identifier Privacy
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Solution Overview
Problem
Existing contact tracing systems face challenges in securely revealing personal identifiers of individuals who have opted-in for contact tracing while protecting the privacy of those who have not, particularly when using ultra-wideband wearable devices that log proximity data.
Innovation Solution
A method utilizing hash functions to securely reveal personal identifiers to a contact tracing entity by generating and processing encounter event data from wearable devices, where the hash values are generated in specific orders based on diagnosis status, ensuring only identical hash values reveal relevant encounters for opt-in individuals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If personal identifiers are revealed to contact tracing entity for effective contact tracing, then contact tracing effectiveness is improved, but privacy protection of non-opt-in users deteriorates
Solution Approach 1:
The system segments users into opt-in and non-opt-in groups, applying different data handling rules. For opt-in users, personal identifiers are revealed to the contact tracing entity, while for non-opt-in users, only hashed identifiers are processed. This segmentation allows the system to achieve effective contact tracing for consenting users while protecting the privacy of those who do not consent.
Solution Approach 2:
A hashing function acts as an intermediary mechanism between raw personal identifiers and the contact tracing entity. The hashing function transforms personal identifiers into hashed identifiers that can be processed for contact tracing purposes without revealing actual personal information. This intermediary layer enables contact tracing functionality while maintaining privacy protection through cryptographic transformation.
2Object-affected harmful factors
If hash values are generated for all encounter data, then privacy protection is improved, but processing efficiency deteriorates
Solution Approach 1:
The system applies hashing selectively rather than universally. Hashing is performed only on identifiers related to opt-in users and only for encounters that are relevant to contact tracing. This partial action approach maintains privacy protection where needed while avoiding the excessive computational overhead of hashing all encounter data, thereby improving processing efficiency.
3Measurement precision
If log data is stored with personal identifiers for accurate contact tracing, then contact tracing accuracy is improved, but data security requirements worsen
Solution Approach 1:
The system changes the parameter of identifier representation from plain text personal identifiers to hashed identifiers. This parameter change maintains the uniqueness and traceability needed for accurate contact tracing while significantly reducing data security requirements. The hashed identifiers preserve the ability to link encounters to specific users without exposing sensitive personal information that would require high-level security protections.
Data Source
Figure 1~3
AI summary
The invention relates to a method for securely revealing a personal identifier of or related to two persons, respectively, to a contact tracing entity of a contact tracing system or method based on detecting relevant encounters between two persons, wherein each of the plurality of persons are wearing or carrying a wearable or portable device, the wearable or portable devices having or being associated or assigned to, respectively, a tag identifier, the tag identifiers being repeatedly broadcast by the wearable or portable devices, respectively, using a wireless communication interface of the wearable or portable devices, thereby generating and/or storing log data from which, respectively, encounter event related data and further encounter event related data are able to be derived, comprising, respectively, both tag identifiers, a computing device or functionality being associated or related to the wearable or portable device, as well as a further computing device or functionality being associated or related to the further wearable or portable device, wherein a hash function is used for securely revealing the personal identifiers in case that the concerned persons are both opting-in for such revealing, the method comprises the following steps: -- in a first step, a relevant encounter of the wearable or portable device and the further wearable or portable device is detected, independently from each other, by the wearable or portable device and the further wearable or portable device, thereby generating and transmitting -- the corresponding encounter event related data, comprising both tag identifiers as well as at least one encounter time stamp information, to the computing device or functionality, and -- the corresponding further encounter event related data, comprising both tag identifiers as well as at least one further encounter time stamp information, to the further computing device or functionality, -- in a second step, the computing device or functionality generates upload data and the further computing device or functionality generates further upload data, both the computing device or functionality and the further computing device or functionality transmitting the respective upload data to the contact tracing entity, wherein -- the computing device or functionality, upon being informed about a diagnosis, especially a positive test result, generates a diagnosis hash value by computing the hash function from a diagnosis hash input information, comprising both tag identifiers in a diagnosis order, especially the wearable or portable device's tag identifier first, the diagnosis hash value as well as the personal identifier being part of the upload data, and -- the further computing device or functionality generates a further hash value by computing the hash function from a hash input information comprising both tag identifiers in a standard order, especially the wearable or portable device's tag identifier first, the further hash value as well as the further personal identifier being part of the further upload data, resulting in the contact tracing entity being able to know, by means of both the diagnosis hash value and the further hash value being identical, about the relevant encounter of the wearable or portable device and the further wearable or portable device as well as of the personal identifiers. (Figure 1)