1. INTRODUCTION

   Blockchain is digital, decentralized technology which maintains a record of all the transactions which happen over a peer-to-peer network. These records are stored in decentralized systems which are interconnected. Blockchains are “tamper evident and tamper resistant digital ledgers implemented in a distributed fashion (i.e., without a central repository) and usually without a central authority (i.e., a bank, company or government)”.

   Blockchain innovation empowers the “production of a decentralized domain, where the cryptographically approved exchanges and information are not under the control of any outsider association”. Any exchange at any point finished is recorded in an unchanging record in a certain, safe, straightforward and perpetual way, with a timestamp and different subtleties.

   Blockchain allows industries to store records of any type on the blockchain. Some of them are:

   • Identity management
   • Business transactions
   • Medical transaction records
   • Transaction processing
   • General documentation
   • Management activities
   1. Public and Private Blockchains
      • Securing applications
      • Auditing
      • Database security
      • Digital workforce training
      • Continuity planning
      • Proper testing methods
   2. Key Principles of Blockchain Which Ensure Safety

      In a public blockchain, anyone can participate in the network. It is a permissionless blockchain where even anonymous people can enter. These use the Proof-of-Work and Proof-of-Stake consensus algorithms. Public blockchains have a low transaction speed.

      Examples: Bitcoin and Ethereum
      Private blockchains ensure privacy and security of data. Here, participation requires an invitation which is validated by a set of rules. There is an added layer of privacy on public blockchains as participant activity for certain transactions is restricted. It uses the voting or multi-party consensus mechanism. It is a lighter blockchain and hence the transaction speed is high.

      Examples: Hyperledger

      
      Figure 1: Nodes in Public vs. Private Blockchains
2. BLOCKCHAIN ARCHITECTURE

   The architectural components have been summed up and after that changed by different organizations, prompting diverse blockchain ventures like Bitcoin, Ethereum, Hyperledger and so on.

   The following is a list of the architectural components:

   • Node - “client or PC inside the blockchain engineering (each has an autonomous duplicate of the entire blockchain record)
   • Transaction - littlest structure square of a blockchain framework (records, data, and so forth.) that fills in as the motivation behind blockchain
   • Block - a data structure utilized for keeping a lot of exchanges (transactions) which is appropriated to all hubs in the system
   • Chain - a grouping of blocks in a particular request
   • Miners - explicit hubs which play out the block confirmation process before adding anything to the blockchain structure
   • Consensus (consensus protocol) - a lot of guidelines and plans to do blockchain activities”.

   Any new record or exchange inside the blockchain suggests the structure of another block. Each record is then demonstrated and carefully marked to guarantee its validity. Before this square is added to the system, it ought to be checked by most of hubs in the framework.

   Coming up next is a blockchain architecture diagram that shows how this really functions as a digital wallet.

   
   Figure 2: Blockchain architecture diagram

   Each blockchain block consists of:

   • certain data
   • the hash of the block
   • the hash from the previous block

   The information put away inside each block relies upon the sort of blockchain. For example, in the Bitcoin blockchain structure, the block keeps up information about the collector, sender, and the amount of coins.

   A hash resembles a unique mark (long record comprising of certain digits and letters). Each block hash is produced with the assistance of a cryptographic hash algorithm (SHA 256). Subsequently, this distinguishes each block in a blockchain structure effectively. The minute a block is made, it consequently appends a hash, while any progressions made in a block influence the difference in a hash as well. Essentially expressed, hashes help to recognize any adjustments in blocks.

   The last component inside the block is the hash from a previous block. This makes a chain of blocks and is the principle component behind blockchain design's security. For instance, block 14 to block 15. The absolute first block in a chain is somewhat exceptional - all affirmed and approved blocks are gotten from the beginning block.

   Any degenerate endeavors incite the blocks to change. All the accompanying blocks at that point convey wrong data and render the entire blockchain framework invalid.

3. BLOCKCHAIN USE CASES

   In this section, we will discuss the top 5 promising use cases of blockchain across various industry verticals.

   1. Supply Chain Management

      The principle issues looked here are:

      • Lack of straightforwardness as the item moves along its production network.
      • Issues in item legitimacy as shoppers can now and again get fake merchandise.

      The production network is a system which is built up between a business and its providers. Blockchain guarantees to discover a solution for inventory network issues through the digitization of benefits. It takes into consideration items to be labeled and relegated with one of kind characters which are then transplanted onto an unchanging, straightforward, and secure blockchain. Blockchain helps in following significant item data, for example, the condition of the item, time span of usability, time, and area. With blockchain-empowered resource digitization set up, an item's production network can be adequately transplanted onto a store network.

      Consumers can verify the authenticity of purchased goods through a blockchain-enabled supply chain. Products can be accurately tracked across different locations and stages in a supply chain. This way, stakeholders will have the capability to isolate and tackle any potential issues.

      
      Figure 3: Blochchain Usecases in Supply Chain (Source: 101blockchains.com)
   2. Digital Identity

      Today, digital identity is becoming problematic as centralized entities are becoming increasingly susceptible to identity thefts and data breaches. Ownership is concentrated in the hands of applications and services to which we provide consent to use our data. Digital identity can be described as an online record of information pertaining to individuals and organizations.

      In a blockchain, users can have control over their information. Instead of providing consent to many service providers, users can store their digital identity data in an encrypted digital hub. Individuals can control access to the hub and can also revoke access, if necessary. Using blockchain technology, the user can be in control of their digital data and the way in which it is utilized.

   3. Healthcare

      Current issues:

      • Medical practitioners lack a clear and complete understanding of a patient’s medical history. This hinders in providing effective healthcare solutions.
      • Counterfeit or fake medicines are also a major issue within the medical supply chain.

      Blockchain will serve as a tamper-proof and secure database to alleviate the problems faced in the healthcare industry. Patient medical records can be stored on a blockchain. This will make it significantly easier for medical practitioners to get a better idea of a patient’s medical history. Blockchain would also help tag and track drugs at every stage of the supply chain. It will act as a medium to assure the authenticity of the drugs. Patients will also have control over the data stored in the blockchain. Others can view their data only if the patients grant them permission for the same.

   4. Notary

      A noteworthy part of possession resources is in paper structure. This leaves space for the records to be altered or exposed to deceitful action. Authentication is a cheat hindrance process which guarantees the gatherings of an exchange that a record can be trusted and is bona fide. Blockchain innovation will increase the value of the procedure of legally approbation. The alter safe and straightforward component of blockchain makes it an appropriate possibility for legally approbation. Blockchain can be utilized in legally approbation to guarantee evidence of-presence. Blockchain helps in demonstrating the presence of the record since the time it was made and alterations can likewise be recognized. Checking if a record has been adjusted or not should be possible by hashing the archive. On the off chance that there has been any change, the report will bring about an alternate hash and the proprietor will end up mindful of the adjustment.

   5. Intellectual Property (IP)

      Poorly maintained IT protocols cause unnecessary legal disputes. Adding a blockchain system can serve as a platform which provides accurate and clear ownership of IP assets. Tamper-resistant blockchains can provide a timestamp to indicate the exact recording time of an idea. This will solve any disputes regarding the origin of an idea. Blockchain also gives intellectual property owners the added advantage of protecting their IP assets infringers, for example, patent trolls.

4. TOP 5 BLOCKCHAIN PLATFORMS FOR DIGITAL MARKETING

   In this section, we will understand the top five blockchain platforms which would suit digital marketing.

   1. Ethereum

      Ethereum is the world’s leading programmable blockchain. Ethereum is a distributed public blockchain network. Ethereum’s primary focus is on running the programming code of any decentralized application. The Ether cryptocurrency of the Ethereum blockchain fuels the network and it is used by application developers to pay for services and transactions on the Ethereum network.

      In digital marketing, hyperledger can be used as the internet to build in money and payments. It assures the security and transparency of data in digital marketing. The tokenization feature of the Ethereum blockchain helps protect credit card numbers and bank account numbers in a secure, virtual vault which can be transmitted across wireless networks. Ethereum will help set up a payment gateway which is needed for tokenization to work in order to store sensitive data which will allow the generation of the random token. The ERC-20 token can also be used for digital marketing transactions as it allows for uniform and fast transactions and confirms the transactions in an efficient manner.

   2. Hyperledger

      This is an open-source collaborative project which has been created to advance cross-industry blockchain technologies. It is a global collaboration which is hosted by the Linux Foundation. Hyperledger will be highly useful in digital marketing as it helps build a new generation of transactional applications which helps establish trust, transparency, and accountability for digital marketers and helps them streamline business processes and legal constraints.

      Its peer-to-peer distributed ledger technology uses a system of smart contracts and other assistive technologies to help digital marketers secure the data related to their company, customers, and business processes. It reduces the cost and complexity of reaching out to customers as it stores information over a shared network which can be viewed by any marketer and customer who has access to the blockchain network. It acts as a decentralized digital operating system for marketplaces and data-sharing networks.

   3. Quorum

      Quorum is a version of the public Ethereum blockchain which has been developed by JP Morgan Chase. Quorum equips the Ethereum blockchain with a top layer and this enables it to perform private transactions and use different consensus algorithms which make it more robust. Quorum is an open source blockchain platform which is designed to support enterprise needs. It is specifically designed to ensure the privacy of private transactions between nodes. The quorum network does not charge for transactions. Security is the cornerstone to any business and digital marketing is no exception. As digital marketing reaches a wide audience, sharing a link to a website that hosts malware and running outdated versions of plugins, themes, and core components makes a network more prone to hacks and security breaches.

      The quorum blockchain is ideal for digital marketing as it meets the organizational requirements of high speed and high throughput of private transactions. Quorum protects information greatly as information which is agreed to be private is never broadcast across the network. Privacy is of utmost importance in a quorum blockchain. Transactions are usually verified through the consensus algorithms. The constellation-transaction manager component of Quorum is responsible for the privacy of transactions. Though the transaction manager stores and allows access to encrypted transaction data and exchanges encrypted payloads, it does not hold access to sensitive private keys. Constellation enclave is another component which leverages cryptographic techniques for historical data preservation, transaction authenticity, and participant authentication. The enclave and transaction manager components of the quorum blockchain work hand in hand to secure and strengthen transaction privacy.

   4. Recordskeeper

      Recordskeeper is an Open Public Mineable Blockchain which is used for record-keeping and data security. It comprises of a full suite of structured and easily accessible record keeping for both individuals and organizations alike. RecordsKeeper capitalizes over the advantages of the blockchain network such as secure transfer, authorization, integrity, and authenticity of data.

      The servers used in centralized systems are prone to tampering, whereas RecordsKeeper is designed in such a manner that the data used for digital marketing is stored and protected over a secure network. RecordsKeeper cuts down costs for saving data as it stores a hash of data which acts as the digital fingerprint.

   5. Corda

      Corda is a flexible and agile open source blockchain platform which can scale to meet the needs of any business. A robust community of developers supports corda by working on enhancements, functionalities, and added features. Corda provides privacy to businesses by enabling them to transact directly in a secure manner using smart contracts. Corda helps streamline business operations and reduces transaction and record-keeping costs.

      Apart from Quorum, digital marketers can also think of leveraging the capabilities of the Quorum blockchain for ensuring transaction privacy and securing business information. Transaction history and transaction data on the corda ledger are encrypted and are shared only with necessary parties. Its interoperable nature allows businesses to transact with each other on the corda network in a free and commercial manner. Digital marketers can use corda as the foundation to help solve the real-world problems of the digital marketing industry and build robust solutions.

5. SUMMARY

   Blockchain is making the impossible possible by allowing people to secure digital relationships. Thanks to the advent of the blockchain, data is now being recorded, disclosed, and secured differently. Due to its tremendous potential, blockchain is being leveraged by many smart and innovative companies for enhancing their business processes and eventually becoming the business leaders of their respective industries.

ABOUT THE AUTHOR
Dr. S. Balakrishnan is a Professor and Head of Department of Computer Science and Business Systems at Sri Krishna College of Engineering and Technology, Coimbatore, Tamilnadu, India. He has 17 years of experience in teaching, research and administration. He has published over 15 books, 3 Book Chapters, 14 Technical articles in CSI Communications Magazine, 1 article in Electronics for You (EFY) magazine, 3 articles in Open Source for You Magazine and over 100 publications in highly cited Journals and Conferences. Some of his professional awards include: Contributors Competition Winner July 2019, by DataScience Foundation, with cash prize of £100, 100 Inspiring Authors of India, Deloitte Innovation Award - Cash Prize Rs.10,000/- from Deloittee for Smart India Hackathon 2018, Patent Published Award, Impactful Author of the Year 2017-18. His research interests are Artificial Intelligence, Cloud Computing and IoT. He has delivered several guest lectures, seminars and chaired a session for various Conferences. He is serving as a Reviewer and Editorial Board Member of many reputed Journals and acted as Session chair and Technical Program Committee member of National conferences and International Conferences at Vietnam, China, America and Bangkok. He has published more than 6 Patents on IoT Applications.