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Decentralised location-based reputation management system in IOT using blockchain
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Resumo(s)
Internet of Things (IoT) allows an object to connect to the internet network and
observe or interact with a physical phenomenon. The communication technologies
allow an IoT device to discover and communicate with another one to exchange
services like humans do in their social network. Knowing the reputation of another
device is important to consider if it will trust before establishing a new connection
to avoid an unexpected behaviour. The reputation of a device can also be varied
depending on its geographical location. Thus, this thesis proposed an architecture
to manage reputation values of end devices in an IoT system, based on their located
area. To avoid a hard workload of the system in the cloud layer, the proposed architecture
follows the cloud-fog-edge concept by adding an intermediate layer called
a fog layer. In this layer, multiple smaller devices are distributed, so it used the
Blockchain technology to keep the reputation management to be consistent and
fault-tolerant across di erent nodes in the layer. Ethereum, which is a Blockchain
implementation, was used in this work to ease the management functionalities, because
it allows the Blockchain network to run a decentralised application through
the Smart Contracts. The location-based part of the system was done by storing
geographical areas in the Smart Contracts, and make the reputation values to be
subjected to di erent regions depending on device geographical location. To reduce
the spatial computation complexity in the Smart Contracts, the geographical
data are geocoded by either one of two di erent spatial indexing techniques called
Geohash and S2. This work introduced three experiments to test the proposed architecture,
to deploy the architecture in IoT devices, and to compare the two geocoding
techniques in the Smart Contracts. It also additionally proposed a compression algorithm
of the geocoded data. The results showed that the proposed architecture is
able to serve the objective of managing the reputation values based on location in
a decentralised way. The test case scenario also demonstrated that the IoT devices
were able to work as a Blockchain node. They also were able to discover the service
providers in an area and obtain their reputation values by querying through the fog
layer. Lastly, the comparison experiment results showed that Geohash performed
better inside the developed Smart Contracts, while S2 encoded the data much faster
outside the Smart Contracts. The proposed compression algorithm of geocoded data
resulted in a signi cant size reduction, but it was computationally heavier in the
developed Smart Contracts.
Descrição
Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies
Palavras-chave
Internet of Things (IoT) Location-Based Trust and Reputation Management Spatial Indexing Ethereum Smart Contract Decentralised Application