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Smart Contracts for Building Access Control
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- Author / Creator
- Leepakshi Bindra
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Large commercial buildings are complex cyber-physical systems containing expensive and critical equipment that ensure the safety and comfort of their numerous occupants. Yet occupant and visitor access to spaces and equipment within these buildings are still managed through unsystematic, inefficient, and human-intensive processes. As a standard practice, long-term building occupants are given access privileges to rooms and equipment based on their organizational roles, while visitors have to be escorted by their hosts.
Existing methods use a centralized infrastructure to delegate access to occupants, and sometimes visitors. A centralized technique is dependent on a single authority and requires the authority to be online all the time. Also, this technique is very vulnerable to failure as the whole system is compromised if the central server is attacked. These shortcomings make the traditional approach conservative and inflexible.
In this thesis, we describe a methodology that can flexibly and securely manage building access privileges for long-term occupants and short-term visitors alike, taking into account the risk associated with accessing each space within the building. Our methodology relies on blockchain smart contracts to describe, grant, audit, and revoke fine-grained permissions for building occupants and visitors, in a decentralized fashion. Access for visitors is described through smart contracts that use information of the event time, destination location and privilege of the individuals. The accessible spaces are specified through a process that leverages the information compiled from Brick and BOT models of the building. BOT representation of the building help plan the spaces to which access should be provided to the visitor. To compute the risk of permitting an individual to enter a space, Brick models are employed to calculate sensitivity and security information of all the spaces.
We illustrate the proposed method through a typical application scenario in the context of a real office building and argue that it can greatly reduce the administration overhead, while, at the same time, providing fine-grained, auditable access control. We design and implement a commercial building simulator that imitates presence and movement of people in the building. The data synthesized by the simulator is used to evaluate the performance of the proposed system. We measure the delay in performing various access management tasks to assess the efficiency of the access management system. Scalability of the proposed solution is determined by calculating throughput and latency of the transactions on the blockchain network. The evaluation concludes that the most common type of requests made to the access management system is to verify access for individuals to a space, which take 0.26 and 0.37 seconds with different loads and computation power, which is typically within the acceptable range in real applications.
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- Subjects / Keywords
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- Graduation date
- Fall 2020
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.