smart city blockchain concept

Smart cities make use of internet technology to maintain physical, social and commercial infrastructure balance. Moreover, a smart city improves services more efficiently while ensuring optimal resource utilisation. Using innovative tech such as cloud computing, interconnected networks and the IoT, smart cities achieve a more direct collaboration between local governments and its citizens.

Despite the advantages, digital disruption still has its own challenges, namely privacy and user security. This post attempts to address the issues using blockchain technology in conjunction with smart devices to build a better communication platform for smart cities.


Urban growth is at an all-time high due to a sharp increase in population, environmental changes and scarcity of resources. Research states that city dwellers are expected to rise up from 54 percent to 66 percent in 2050. Cities and local government are now looking at modern technology to reduce and optimise resource consumption. Significant improvement in technology, namely wireless communications and the Internet of Things make it easier to connect various devices and operate on them via remote access. Since they communicate in more open-ended platforms and could contain personal and vital information, it’s of utmost importance that the network is secured and protected against cyber attacks.

Kaspersky Lab reveals that public systems such as information kiosks, bike rental terminals and self-service machines have a number of glaring security flaws, which make them vulnerable to cybercriminals. Implementing traditional security systems in order to build on the smart element has failed. The solution? Newer tech such as blockchain can open up better communication and data channels without compromising security and privacy.

Security Threats

A smart city is largely vulnerable to various security attacks as their resource devices are heterogenous in nature. In order to be protected from online threats, the local government has looked into various fields, including OWASP, or Open Web Application Security Project for collating the most common security threats, CERT, or Computer Emergency Response Teams for graphical representations of potential vulnerabilities, and CCSP, or Cloud Computing Service Provider for G-Cloud requirements.

The threats surrounding smart cities include the following:

i) Availability Threats, which concern unauthorised usage of resources.
ii) Integrity Threats, which include data corruption and unauthorised manipulation.
iii) Confidentiality Threats, which include unauthorised disclosure of sensitive data.
iv) Authenticity Threats, which include unauthorised access to sensitive information and resources.
v) Accountability Threats, which include transmission or reception message denial by entities.

A Security Framework

A. Blockchain Technology

Blockchain is a P2P, ledger-based platform that can handles many data aspects such as sales, contracts, agreements and transactions. Blockchain’s claim to fame is cryptocurrency, but its architecture is such that it can be easily applied in other industries. One of the greatest strengths of blockchain is that the attacker must control at least 51 percent of the ledger to manipulate transactions and records contained within.

Here’s how blockchain technology works. For example, a blockchain system could be a parking lot. User A pays the fee to B, the authority. The transaction is recorded in the ledger, along with a list of prior transactions, proof of work, block number and other records. Every transaction is broadcast to all entities within the parking system. Other users confirm the block and if more than 50 percent of all entities approve of it, then the transaction passes and the fee is transferred from User A to User B’s account.

B. Security Framework

1. Physical Layer

As shown in Fig. 1, a smart city device can be equipped with actuators and sensors that collate and send the data up to higher protocols. Some of these smart devices, such as the Acer FitBit and the Nest Thermostat, are inherently vulnerable to attacks because of lack of control mechanisms and encryption. Moreover, each smart device doesn’t have a single standard, thereby the data they generate can be integrated for cross-functionality features. Vendors will have to come up with communication standards and implementation to patch these security holes.

2. Communication Layer

Smart city networks use a variety of communication signals such as 3G, 4G, WiFi, Ethernet, Bluetooth and 6LoWPAN to relay data across smart devices. Blockchain presents a significant benefit in adding privacy and security to the data that crosses these networks. Ethereum can be used to provide smart contracts; BitTorrent is a great platform for P2P communication, and transactional data can be converted into blocks via telehash, which is then broadcast to the receiving network. Blockchain technology integration can prove to be a challenge because each application have their own set of requirements. A probable solution includes implementation of blockchain access layers via multiple blockchains for each specific functionality.

3. Database Layer

Distributed ledgers in blockchains form a decentralised database, containing details such as cryptographic signatures and a time stamp. The complete history of transaction is auditable and verifiable by all legitimate participants. Currently, there are 2 kinds of distributed ledger, i) permissionless and ii) permissioned.

Permissionless has the benefit of being transparent and censorship-resistant but at the cost of time (to reach consensus) and the need to maintain a complex shared record. Moreover, public records may be attacked anonymously at any time. Private ledgers, on the other hand are more secure, offer better performance and scalability for a variety of applications, i.e., managing traffic systems and more.

4. Interface Layer

A number of smart apps can be combined together to make more effective decisions. A smart phone can send out a command to a smart home system, allowing the smart home system to start the AC unit five minutes before you arrive. Vulnerabilities in each device must be considered and taken care of to prevent unauthorised access from attackers.

blockchain smart cities

Fig 1. A smart city security framework


This posts aim is to promote the idea of using blockchain technology to secure communication and data transmission in smart cities. Blockchain’s main appeal is its high security feature. With it, a smart city can enjoy faster and smoother operations, better fault tolerance, improved reliability and scalability. The integration of blockchain with smart devices in a smart city presents a singular platform where there’s secure communication within a distributed environment. The proposal is to build a system level model that explores scalability and inter-operability with different platforms that can be found in a smart city.


Yotta CEO Gary Spence at the World Cities Summit, Singapore, July 2018


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