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Corona Heatmap

Software solution for pricacy-perserving health data analytics

The CoronaHeatmap shows where Corona patients were when they got infected. This heat map can help to determine hotspots for infections with SARS-CoV-2. Our solution is designed to protect the privacy of every Austrian citizen through state-of-the-art encryption technology.

Please note: We only used simulated data for the development of this technology - i.e., the images are just exemplary.


An essential factor in the fight against Corona is the knowledge of the places where people get most likely infected. This insight helps the officials to take specific and effective measures.

The health authority posses a list of Sars-Cov-2 patients and corresponding mobile phone numbers. It sends them to a mobile network provider. The mobile network provider responds with the location data of those mobile phone numbers. Due to the requested location data, the health authority can detect the places where most of the Sars-Cov-2 got infected.


Two data sets are needed. First, the mobile numbers of the Corona patients, which are in posession of the health authority. Second, the location data, which are in posession of the mobile carrier.

Through the request from the health authority, the mobile network operator gets to know the identity of Sars-Cov-2 patients. On the other side, the health authority learns the movement patterns of individual persons.

Data-Privacy is not guaranteed, because
  1. the location data of the patients are leaked and
  2. individual surveillance is made possible.


Guaranteed data protection through encryption: Instead of hoping that nobody misuses the data, we rely on mathematical security. Our solution to protect personal data is twofold:

  1. Location data is aggregated to prevent the tracking of individual persons.
  2. The data of patients are protected with state-of-the-art encryption, called homomorphic encryption. Homomorphic Encryption enables us for the first time to compute on encrypted data without decrypting it.

More concretely, the mobile phone number gets encrypted before sending them to the mobile network operator. The mobile network operator then computes the heat map.
Through the use of homomorphic encryption, this computation can be done without decrypting the mobile phone numbers of the patients. The result is an encrypted CoronaHeatMap. The health authority owns the only key able to decrypt the map.


About us

The CoronaHeatmap is a collaborative effort by the Know-Center and the TU Graz Institute of Applied Information Processing and Communications (IAIK). On the one hand, Know-Center is Austria’s leading research center for Big Data. On the other hand, the IAIK is one of the leading research institutions in cybersecurity and amongst others active in the area of Cryptology and Privacy. Together the Know-Center and the IAIK provide a unique competence in privacy-preserving data analytics.


As researchers, transparency is the only option for us. Therefore, the whole project is open source and can be downloaded on GitHub (only code, no data). In addition, we have written a research paper. There, we describe all the technical details of our program and give in-depth argumentation for the privacy of our solution.


Feel free to get in touch with us. Just send an e-email to

Alexander Grass

Mario Barbara

Fabian Schmid