Patent EP-4030788-A1 (EP)
Title: 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, system, computing device or functionalities and wearable or portable devices, program and computer-readable medium
Inventor: ROLLIN HANNES
IPC: G06F21/62
Filed: 2021-01-18
Abstract: 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)