  Recently, as a consequence of the COVID-19 pandemic, dependence on Contact
Tracing (CT) models has significantly increased to prevent spread of this
highly contagious virus and be prepared for the potential future ones. Since
the spreading probability of the novel coronavirus in indoor environments is
much higher than that of the outdoors, there is an urgent and unmet quest to
develop/design efficient, autonomous, trustworthy, and secure indoor CT
solutions. Despite such an urgency, this field is still in its infancy. The
paper addresses this gap and proposes the Trustworthy Blockchain-enabled system
for Indoor Contact Tracing (TB-ICT) framework. The TB-ICT framework is proposed
to protect privacy and integrity of the underlying CT data from unauthorized
access. More specifically, it is a fully distributed and innovative blockchain
platform exploiting the proposed dynamic Proof of Work (dPoW) credit-based
consensus algorithm coupled with Randomized Hash Window (W-Hash) and dynamic
Proof of Credit (dPoC) mechanisms to differentiate between honest and dishonest
nodes. The TB-ICT not only provides a decentralization in data replication but
also quantifies the node's behavior based on its underlying credit-based
mechanism. For achieving high localization performance, we capitalize on
availability of Internet of Things (IoT) indoor localization infrastructures,
and develop a data driven localization model based on Bluetooth Low Energy
(BLE) sensor measurements. The simulation results show that the proposed TB-ICT
prevents the COVID-19 from spreading by implementation of a highly accurate
contact tracing model while improving the users' privacy and security.
