  During pandemics, health officials usually recommend access monitoring and
regulation protocols/systems in places that are major activity centres. As
organizations adhere to those recommendations, they often fail to implement
proper privacy requirements to prevent privacy loss of the users of those
protocols or systems. This is a very timely issue as health authorities across
the world are increasingly putting these regulations in place to mitigate the
spread of the current pandemic. A number of solutions have been proposed to
mitigate these privacy issues existing in current models of contact tracing or
access regulations systems. However, a prevalent pattern among these solutions
are they mainly focus on protecting users privacy from server side and involve
Bluetooth based ephemeral identifier exchange between users. Another pattern is
all the current solutions try to solve the problem in city-wide or nation-wide
level. In this paper, we propose a system, PAARS, which approaches the privacy
issues in access monitoring/regulation systems from a micro level. We solve the
privacy issues in access monitoring/regulation systems without any exchange of
any ephemeral identifiers between users. Moreover, our proposed system provides
privacy on both server side and the user side by using secure hashing and
differential privacy mechanism.

Cryptography and Security