In layman terms, a “block chain” (or blockchain) is a technology concept that enables transactions between one or more entities who don’t inherently trust each other. It does this without requiring a central authority to assert trust and as a bonus, it also allows for a complete history of transactions to be traced back to the source at any point of time.
Let’s translate this to a concrete example. Block chains allows many users to buy/sell products with digital currency without requiring a bank to authorize payment. The technology inherently is able to identify and discard commonly occurring fraudulent situations like, for example, a person giving another person “digital cash” he or she does not really have. Further, should some form of payment discrepancy occur in the future, anyone using this technology can trace back all the transactions to find out the history that led to this situation without, again, requiring a central authority.
The example above relates to how “digital currency” can be used as an application leveraging block chains. Indeed, this is what bitcoin is all about (Satoshi Nakamoto’s now famous 2009 paper  introduced this concept in its entirety on how block chains could be used as a replacement to the current flaws in our currency economy). While this concept was not new  it gained a lot of popularity as it took a more novel approach to addressing known attacks compared to other solutions.
Given that “currency” was the first application of blockchain, a lot of people associate the core technology (blockchain) with a specific application of it (currency, aka bitcoin).
However, the technology community understood the much wider applicability of this distributed trust system and since then, blockchains have been proposed, and indeed adopted in many other verticals  that have similar issues of trust, verification and traceability.
This brief paper will talk about how blockchains can be effectively used in IoT Networks
For the scope of this paper, an “IoT Network” is a system comprising of a few or many sensors devices and network servers, somehow connected to form a network where they can exchange data with each other as required to be able to provide specific value-added services. For example, “Amazon’s Alexa System” is an “IoT Network” comprising of Alexa-enabled voice gateways, bridges to talk to sensors like room temperatures, fans as well as complex devices like cars  for the purpose of providing a “Home Assistant service” that can enable consumers to control all aspects of their home just by speaking. There are many other examples of IoT networks like an “IoT Network” that monitors agricultural produce for crop damage (via image analytics, weather sensors, etc.), or an “IoT Network” that helps our military perform search and rescue (via communicating drones, heat sensors, etc).
In discussing any new approach for a system, its useful to first understand the pain points being faced and then see if the solution we are proposing helps in addressing the problems in any tangible way. This section will briefly touch upon the key characteristics of an IoT network:
There are many other characteristics and pain points, but for the scope of this paper, lets discuss more on the adoption of Blockchains in IoT networks
Are blockchains therefore ideal for IoT security? That would be a Yes and No. There are inherent issues with blockchains that cause issues in IoT which need to be resolved. Indeed, many of these issues are already being addressed and IoT networks of today are proposing modifications to Blockchains that are more applicable to these networks, such as HDAC 
Some of the issues that are being dealt with:
Blockchain based private and public networks have become an important part of distributed trust and security in the IoT powered network. HSC works with ISVs/OEMs and Service Providers alike, helping them engineer and customize solutions around block-chains. Some areas of focus are: