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Blockchain of Things (BCoT): The Fusion of Blockchain and IoT Technologies

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Advanced Applications of Blockchain Technology

Part of the book series: Studies in Big Data ((SBD,volume 60))

Abstract

Blockchain, as well as Internet of Things (IoT), is considered as two major disruptive emerging technologies. However, both of them suffer from innate technological limitations to some extent. IoT requires strengthening its security features while Blockchain inherently possesses them due to its extensive use of cryptographic mechanisms and Blockchain––in an inverted manner–– needs contributions from the distributed nodes for its P2P (Peer-to-Peer) consensus model while IoT rudimentarily embodies them within its architecture. This chapter, therefore, acutely dissects the viability, along with prospective challenges, of incorporating Blockchain with IoT technologies––inducing the notion of Blockchain of Things (BCoT)––as well as the benefits such consolidation can offer.

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References

  1. Atzori, L., Iera, A., Morabito, G.: The Internet of Things: a survey. Comput. Netw. 54(15), 2787–2805 (2010). https://doi.org/10.1016/j.comnet.2010.05.010

    Article  Google Scholar 

  2. Balasubramaniam, S., Kangasharju, J.: Realizing the Internet of Nano Things: challenges, solutions, and applications. Computer 46(2), 62–68 (2013). https://doi.org/10.1109/mc.2012.389

    Article  Google Scholar 

  3. Benattia, A., Ali, M.: Convergence of technologies in the machine-to-machine (M2M) space. In: Proceedings of the IEEE Internationa Conference on Applied Electronics 2008, pp. 9–12. IEEE, Pilsen, Czech Republic (2008)

    Google Scholar 

  4. Chakraborty, R.B., Pandey, M., Rautaray, S.S.: Managing computation load on a blockchain—based multi-layered Internet-of-Things network. Procedia Comput. Sci. 132, 469–476 (2018). https://doi.org/10.1016/j.procs.2018.05.146

    Article  Google Scholar 

  5. Chaudhry, J., Saleem, K., Haskell-Dowland, P., Miraz, M.H.: A survey of distributed certificate authorities in MANETs. Ann. of Emerg. Technol. Comput. (AETiC) 2(3), 11–18 (2018). https://doi.org/10.33166/aetic.2018.03.002

    Article  Google Scholar 

  6. Christidis, K., Devetsikiotis, M.: Blockchains and smart contracts for the Internet of Things. IEEE Access 4, 2292–2303 (2016). https://doi.org/10.1109/access.2016.2566339

    Article  Google Scholar 

  7. Daia, A.S., Ramadan, R.A., Fayek, M.B.: Sensor networks attacks classifications and mitigation. Ann. Emerg. Technol. Comput. (AETiC) 2(4), 28–43 (2018). https://doi.org/10.33166/aetic.2018.04.003

    Article  Google Scholar 

  8. Deters, R.: Decentralized access control with distributed ledgers. In: Proceedings of the International Conference on Cloud and Robotics (ICCR 2017), Saint-Quentin, France (2017). http://www.cloudrobotics.info/files/papers/ICCR17_paper_6.pdf. Accessed 1 Apr 2019

  9. Donald, D.C., Miraz, M.H.: Restoring direct holdings and unified pricing to securities markets with distributed ledger technology. SSRN (2019). https://papers.ssrn.com/sol3/papers.cfm?abstract_id=%203352293

  10. Dorri, A., Kanhere, S.S., Jurdak, R.: Blockchain in Internet of Things: challenges and solutions. ArXiv (2016, August 18). https://arxiv.org/abs/1608.05187. Accessed 1 Apr 2019

  11. Dorri, A., Kanhere, S.S., Jurdak, R., Gauravaram, P.: Blockchain for IoT security and privacy: the case study of a smart home. In: Proceedings of the IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom 2017), pp. 618–623. IEEE, Kona, HI, USA (2017). https://doi.org/10.1109/percomw.2017.7917634

  12. Evans, D.: The Internet of Things: How the Next Evolution of the Internet is Changing Everything. Cisco Systems, Inc., Cisco Internet Business Solutions Group (IBSG). Cisco IBSG, San Jose, CA, USA (2011). http://www.cisco.com/web/about/ac79/docs/innov/IoT_IBSG_0411FINAL.pdf. Accessed 21 Jan 2015

  13. Evans, D.: The Internet of Everything: How More Relevant and Valuable Connections Will Change the World. Cisco Systems, Inc., Cisco Internet Business Solutions Group (IBSG). Cisco IBSG, San Jose, CA, USA (2012). https://www.cisco.com/web/about/ac79/docs/innov/IoE.pdf. Accessed 21 Jan 2015

  14. Feki, M.A., Kawsar, F., Boussard, M., Trappeniers, L.: The Internet of Things: the next technological revolution. Computer 46(2), 24–25 (7 Feb 2013). https://doi.org/10.1109/mc.2013.63

    Article  Google Scholar 

  15. Gartner: Top trends in the gartner hype cycle for emerging technologies. Gartner, Inc. (2017). https://www.gartner.com/newsroom/id/3784363. Accessed 19 Sept 2017

  16. Höller, J., Tsiatsis, V., Mulligan, C., Avesand, S., Karnouskos, S., Boyle, D.: From Machine-to-Machine to the Internet of Things: Introduction to a New Age of Intelligence, 1st edn. Academic Press Ltd., London, UK (2014, April 10)

    Chapter  Google Scholar 

  17. IOTA Foundation: The Tangle: no blocks, no chain. Research Report, IOTA Foundation, Berlin, Germany (2018). https://www.iota.org/research/meet-the-tangle. Accessed 13 July 2018

  18. Jesus, E.F., Chicarino, V.R., Albuquerque, C.V., Rocha, A.A.: A survey of how to use blockchain to secure Internet of Things and the stalker attack. Secur. Commun. Netw. 2018, 1–27 (2018). https://doi.org/10.1155/2018/9675050

    Article  Google Scholar 

  19. Kouicem, D.E., Bouabdallah, A., Lakhlef, H.: Internet of things security: a top-down survey. Comput. Netw. 141, 199–221 (2018, August 4). https://doi.org/10.1016/j.comnet.2018.03.012

    Article  Google Scholar 

  20. LO3 Energy: Exercy: building a robust value mechanism to facilitate transactive energy. LO3 (2017). https://exergy.energy/wp-content/uploads/2017/11/Exergy-Whitepaper-v7.pdf. Accessed 29 Mar 2019

  21. Miraz, M.H.: Blockchain: technology fundamentals of the trust machine. Machine Lawyering (2017, December 23). https://doi.org/10.13140/rg.2.2.22541.64480/2

  22. Miraz, M.H., Ali, M.: Blockchain enabled enhanced IoT ecosystem security. In: Proceedings of the International Conference on Emerging Technologies in Computing 2018 (iCETiC 2018). Part of the Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering (LNICST), vol. 200, pp. 38–46. Springer, London, UK (2018). https://doi.org/10.1007/978-3-319-95450-9_3

    Google Scholar 

  23. Miraz, M.H., Donald, D.C.: Application of blockchain in booking and registration systems of securities exchanges. In: Proceedings of the IEEE International Conference on Computing, Electronics & Communications Engineering 2018 (IEEE iCCECE 2018), 16–17 August 2018. IEEE, Southend, UK (2018)

    Google Scholar 

  24. Miraz, M.H., Donald, D.C.: Atomic cross-chain swaps: development, trajectory and potential of non-monetary digital token swap facilities. In: Ware, A. (ed.) Annals of Emerging Technologies in Computing (AETiC), 1 January 2019, vol. 3, no. 1, pp. 42–50 (2019). https://doi.org/10.33166/aetic.2019.01.005

    Article  Google Scholar 

  25. Miraz, M.H., Donald, D.C.: LApps: technological, legal and market potentials of blockchain lightning network applications. In: Proceedings of the 2019 International Conference on Information System and Data Mining (ICISDM 2019). ACM, Houston, USA (2019). https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3348944

  26. Miraz, M.H., Peter, S.E.: Evaluation of green alternatives for blockchain proof-of-work (PoW) approach. In: Proceeings of Global 2019 Congress on Communications and Computing Technologies (GC-Technology 2019), Istanbul, Turkey (2019)

    Google Scholar 

  27. Miraz, M.H., Ali, M., Excell, P.S., Picking, R.: Internet of nano-things, things and everything: future growth trends. (Invit. Pap.) Futur. Internet 10(8) (2018). https://doi.org/10.3390/fi10080068

    Article  Google Scholar 

  28. Miraz, M.H., Ali, M., Excell, P., Rich, P.: A review on Internet of Things (IoT), Internet of Everything (IoE) and Internet of Nano Things (IoNT). In: Picking, R., Cunningham, S., Houlden, N., Oram, D., Grout, V., Mayers, J. (eds.) The Proceedings of the Fifth International IEEE Conference on Internet Technologies and Applications (ITA 15), pp. 219–224. Creative and Applied Research for the Digital Society (CARDS), Glyndŵr University, Wrexham, UK (2015). https://doi.org/10.1109/itecha.2015.7317398

  29. Onik, M.M., Al-Zaben, N., Hoo, H.P., Kim, C.-S.: A novel approach for network attack classification based on sequential questions. Ann. Emerg. Technol. Comput. (AETiC) 2(2), 1–14 (2018). https://doi.org/10.33166/aetic.2018.02.001

    Article  Google Scholar 

  30. Onik, M.M., Miraz, M.H., Kim, C.-S.: A recruitment and human resource management technique using blockchain technology for industry 4.0. In: Proceeding of Smart Cities Symposium (SCS-2018), pp. 11–16. The Institution of Engineering and Technology (IET), Manama, Bahrain (2018)

    Google Scholar 

  31. Panarello, A., Tapas, N., Merlino, G., Longo, F., Puliafito, A.: Blockchain and IoT integration: a systematic survey. Sensors 18(8), 1–37 (2018). https://doi.org/10.3390/s18082575

    Article  Google Scholar 

  32. Panetta, K.: 5 trends emerge in the gartner hype cycle for emerging technologies. Smarter With Gartner (2018, August 16). https://www.gartner.com/smarterwithgartner/5-trends-emerge-in-gartner-hype-cycle-for-emerging-technologies-2018/. Accessed 7 Jan 2019

  33. Prabhu, K., Prabhu, K.: Converging blockchain technology with the internet of things. Int. Educ. Res. J. 3(2), 122–123 (2017). http://ierj.in/journal/index.php/ierj/article/view/727. Accessed 31 Mar 2019

  34. Protocol Labs: Filecoin: A Decentralized Storage Network. Filecoin, USA (2017). https://filecoin.io/filecoin.pdf. Accessed 29 Mar 2019

  35. Reyna, A., Martín, C., Chen, J., Soler, E., Díaz, M.: On blockchain and its integration with IoT. Challenges and opportunities. Futur. Gener. Comput. Syst. 88, 173–190 (2018). https://doi.org/10.1016/j.future.2018.05.046

    Article  Google Scholar 

  36. Samaniego, M., Deters, R.: Blockchain as a service for IoT. In: Proceedings of the 2016 IEEE International Conference on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData). IEEE, Chengdu, China (2016). https://doi.org/10.1109/ithings-greencom-cpscom-smartdata.2016.102

  37. Sicari, S., Rizzardi, A., Cappiello, C., Miorandi, D., Coen-Porisini, A.: Toward data governance in the Internet of Things. In: New Advances in the Internet of Things, Part of the Studies in Computational Intelligence (SCI) Book Series, vol. 715, pp. 59–74. Springer, Cham, Germany (2017). https://doi.org/10.1007/978-3-319-58190-3_4

    Google Scholar 

  38. Sun, J., Yan, J., Zhang, K.Z.: Blockchain-based sharing services: what blockchain technology can contribute to smart cities. Financ. Innov. 2(26), 1–9 (2016). https://doi.org/10.1186/s40854-016-0040-y

  39. Szabo, N.: Smart contracts: formalizing and securing relationships on public networks. First Monday 2(9) (1997, September 1). http://ojphi.org/ojs/index.php/fm/article/view/548/469#1. Accessed 13 July 2018

  40. Weissberger, A.: TiECon 2014 summary-part 1: qualcomm keynote & IoT track overview. IEEE ComSoc (2014). https://community.comsoc.org/blogs/alanweissberger/tiecon-2014-summary-part-1-qualcomm-keynote-iot-track-overview. Accessed 19 Jan 2015

  41. Wörner, D., Bomhard, T.: When your sensor earns money: exchanging data for cash with Bitcoin. In: Proceedings of the 2014 ACM International Joint Conference on Pervasive and Ubiquitous Computing: Adjunct Publication, pp. 295–298. ACM, Washington, DC, USA (2014). https://doi.org/10.1145/2638728.2638786

References for Advance/Further Reading

  1. Akyildiz, I.F., Jornet, J.M.: The Internet of Nano-Things. IEEE Wirel. Commun. 17(6), 58–63 (2010). https://doi.org/10.1109/mwc.2010.5675779

    Article  Google Scholar 

  2. Akyildiz, I.F., Pierobon, M., Balasubramaniam, S., Koucheryavy, Y.: The Internet of Bio-Nano Things. IEEE Commun. Mag. 53(3), 32–40 (2015). https://doi.org/10.1109/mcom.2015.7060516

    Article  Google Scholar 

  3. Alansari, Z., Anuar, N.B., Kamsin, A., Soomro, S., Belgaum, M.R., Miraz, M.H., Alshaer, J.: Challenges of Internet of Things and big data integration. In: Proceedings of the International Conference on Emerging Technologies in Computing 2018 (iCETiC 2018). Part of the Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering (LNICST), vol. 200, pp. 47–55. Springer, London, UK (2018). https://doi.org/10.1007/978-3-319-95450-9_4

    Google Scholar 

  4. Ali, N.A., Abu-Elkheir, M.: Internet of Nano-Things healthcare applications: requirements, opportunities, and challenges. In: Proceedings of 11th IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob’ 2015), pp. 9–14. IEEE, Abu Dhabi, United Arab Emirates (2015). https://doi.org/10.1109/wimob.2015.7347934

  5. Back, A.: Hashcash—a denial of service counter-measure. Technical Report, Hashcash (2002). http://www.hashcash.org/papers/hashcash.pdf. Accessed 4 June 2018

  6. Barbier, J., Bhatia, P.K., Kapoor, D.: Internet of Everything in ASEAN: Driving Value and Opportunity in Oil and Gas, Utilities, and Transportation. Cisco Systems, Inc., Cisco Internet Business Solutions Group (IBSG). Cisco IBSG, San Jose, CA, USA (2014). http://www.cisco.com/web/about/ac79/docs/IoE/IoE-in-ASEAN.pdf. Accessed 21 Jan 2015

  7. Botnet, C. (2012). Internet census 2012: port scanning/0 using insecure embedded devices. SourceForge. Slashdot Media. http://census2012.sourceforge.net/paper.html

  8. Bradley, J., Barbier, J., Handler, D.: Embracing the Internet of Everything to Capture Your Share of $14.4 Trillion: More Relevant, Valuable Connections Will Improve Innovation, Productivity, Efficiency & Customer Experience. Cisco Systems, Inc., Cisco Internet Business Solutions Group (IBSG). Cisco IBSG, San Jose, CA, USA (2013). http://www.cisco.com/web/about/ac79/docs/innov/IoE_Economy.pdf. Accessed 21 Jan 2015

  9. Bradley, J., Loucks, J., Macaulay, J., Noronha, A.: Internet of Everything (IoE) Value Index: How Much Value are Private-Sector Firms Capturing from IoE in 2013? Cisco Systems, Inc., Cisco Internet Business Solutions Group (IBSG). Cisco IBSG, San Jose, CA, USA (2013). http://internetofeverything.cisco.com/sites/default/files/docs/en/ioe-value-index_Whitepaper.pdf. Accessed 19 Jan 2015

  10. Bradley, J., Reberger, C., Dixit, A., Gupta, V., Macaulay, J.: Internet of Everything (IoE): Top 10 Insights from Cisco’s IoE Value at Stake Analysis for the Public Sector. Cisco Systems, Inc., Cisco Internet Business Solutions Group (IBSG). Cisco IBSG, San Jose, CA, USA (2013). http://www.cisco.com/web/about/ac79/docs/IoE/IoE-VAS_Public-Sector_Top-10-Insights.pdf

  11. Chaudhry, J., Qidwai, U., Miraz, M.H., Ibrahim, A., Valli, C.: Data security among ISO/IEEE 11073 compliant personal healthcare devices through statistical fingerprinting. In: The Proceedings of the 9th IEEE-GCC Conference and Exhibition 2017, 9–11 May 2017, pp. 319–324. IEEE, Manama, Bahrain (2017)

    Google Scholar 

  12. EOT Coin: IoT needs EOT. Research Report, EOT Coin (2018). https://eotcoin.org/. Accessed 13 July 2018

  13. Evans, D.: How will the Internet of everything impact teachers’ roles in the connected classroom? Ask the Futurist (2013, September 12). http://blogs.cisco.com/ioe/connected-classroom/. Accessed 15 Jan 2015

  14. Evans, D.: Why connections (not things) will change the world. Cisco Blogs (2013, August 27). http://blogs.cisco.com/ioe/why-connections-not-things-will-change-the-world/. Accessed 21 Jan 2015

  15. Fongen, A.: Identity management and integrity protection in the Internet of Things. In: IEEE Third International Conference on Emerging Security Technologies, 5–7 September 2012, pp. 111–114. IEEE, Lisbon, Portugal (2012). https://doi.org/10.1109/est.2012.15

  16. Khan, S., Shayokh, M.A., Miraz, M.H., Bhuiyan, M.: A framework for Android based shopping mall applications. In: Ali, M., Miraz, M.H., Kunasekaran, K.K. (eds.) Proceedings of the International Conference on eBusiness, eCommerce, eManagement, eLearning and eGovernance (IC5E 2014), pp. 27–32. Association of Scientists, Developers and Faculties (ASDF), University of Greenwich, London, UK.

    Google Scholar 

  17. Loughran, J.: Graphene radios could unlock ‘Internet of Nano-Things’. Eng. Technol. (E&T) (2016). https://eandt.theiet.org/content/articles/2016/11/graphene-radios-could-unlock-internet-of-nano-things/

  18. Mahoney, J., LeHong, H.: Innovation Insight: The ‘Internet of Everything’ Innovation Will Transform Business. Gartner, Inc., Stamford, Connecticut, USA (2012). https://www.gartner.com/doc/1886915/innovation-insight-internet-everything-innovation. Accessed 21 Jan 2015

  19. Marvin, R.: The 5 worst hacks and breaches of 2016 and what they mean for 2017. PC Mag. (2017). https://www.pcmag.com/article/350793/the-5-worst-hacks-and-breaches-of-2016-and-what-they-mean-fo. Accessed 18 June 2018

  20. Mena, D.M., Papapanagiotou, I., Yang, B.: Internet of Things: survey on security. Inf. Secur. J. Global Perspect. 27(3), 162–182 (2018). https://doi.org/10.1080/19393555.2018.1458258

    Google Scholar 

  21. Miraz, M.H., Khan, S., Bhuiyan, M., Excell, P.: Mobile academy: a ubiquitous mobile learning (mLearning) platform. In Ali, M., Miraz, M.H., Kunasekaran, K.K. (eds.) Proceedings of the International Conference on eBusiness, eCommerce, eManagement, eLearning and eGovernance (IC5E 2014), pp. 89–95. Association of Scientists, Developers and Faculties (ASDF), University of Greenwich, London, UK (2014).

    Google Scholar 

  22. Mitchell, S., Villa, N., Stewart-Weeks, M., Lange, A.: The Internet of Everything for Cities: Connecting People, Process, Data, and Things to Improve the ‘Livability’ of Cities and Communities. Cisco Systems, Inc., Cisco Internet Business Solutions Group (IBSG). Cisco IBSG, San Jose, CA, USA (2013). http://www.cisco.com/web/strategy/docs/gov/everything-for-cities.pdf. Accessed 19 Jan 2015

  23. Nakamoto, S.: Bitcoin: a peer-to-peer electronic cash system. White Paper, Bitcoin (2008). https://bitcoin.org/bitcoin.pdf. Accessed 31 May 2018

  24. Rahman, A., Ali, M.: Analysis and evaluation of wireless networks by implementation of test security keys. In: Proceedings of the International Conference on Emerging Technologies in Computing 2018 (iCETiC 2018). Springer, London, UK (n.d.)

    Google Scholar 

  25. Roman, R., Najera, P., Lopez, J.: Securing the Internet of Things. Computer 44(9), 51–58 (2011). https://doi.org/10.1109/mc.2011.291

    Article  Google Scholar 

  26. Shashank: Blockchain technology—unfolding the technology behind bitcoins. edureka! (2017). https://www.edureka.co/blog/blockchain-technology/

  27. Soomro, S., Miraz, M.H., Prasanth, A., Abdulla, M.: Artificial intelligence enabled IoT: traffic congestion reduction in smart cities. In: Proceedings of the IET 2018 Smart Cities Symposium (SCS 2018), 22–23 April 2018, pp. 81–86. IET, Bahrain (2018)

    Google Scholar 

  28. Stankovic, J.A.: Research directions for the Internet of Things. IEEE Internet Things J. 1(1), 3–9 (2014). https://doi.org/10.1109/jiot.2014.2312291

    Article  MathSciNet  Google Scholar 

  29. Vanhoef, M., Piessens, F.: Key reinstallation attacks: forcing nonce reuse in WPA2. In: Proceedings of the ACM Conference on Computer and Communications Security (CCS). Association for Computing Machinery (ACM), Dallas, USA, 30 October 2017. https://papers.mathyvanhoef.com/ccs2017.pdf

  30. Vermesan, O., Friess, P.: Internet of Things: Converging Technologies for Smart Environments and Integrated Ecosystems, 1st edn. River Publishers, Aalborg, Denmark (2013, July 2). http://www.internet-of-things-research.eu/pdf/Converging_Technologies_for_Smart_Environments_and_Integrated_Ecosystems_IERC_Book_Open_Access_2013.pdf. Accessed 18 June 2018

  31. Weber, R.H.: Internet of Things—new security and privacy challenges. Comput. Law Secur. Rev. 26(1), 23–30 (2010). https://doi.org/10.1016/j.clsr.2009.11.008

    Article  MathSciNet  Google Scholar 

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  1. The Chinese University of Hong Kong (CUHK), Sha Tin, Hong Kong

    Mahdi H. Miraz

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  1. School of Integrated Technology, Yonsei University, Incheon, Korea (Republic of)

    Shiho Kim

  2. RDSD&E, NE Region, Guwahati, Assam, India

    Ganesh Chandra Deka

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Miraz, M.H. (2020). Blockchain of Things (BCoT): The Fusion of Blockchain and IoT Technologies. In: Kim, S., Deka, G. (eds) Advanced Applications of Blockchain Technology. Studies in Big Data, vol 60. Springer, Singapore. https://doi.org/10.1007/978-981-13-8775-3_7

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