Blockchain and Healthcare

Blockchain technology is an emerging field of IT that has revolutionized several industries including banking, education, IOT, governance, etc., and is now making its way into the healthcare industry as well [21]. It is transforming the way the health records are being kept and businesses being planned. Blockchain technology provides a distributed and decentralized healthcare ecosystem to assist patients as well as providers. It delivers services for managing health records, health insurance management and medicinal research for social benefits. The blockchain distributed network keeps the data available in real time in encrypted form on a ledger that is decentralized. The basic properties of the blockchain technology that make it best suitable for healthcare domain are given below, and Table 7.2 discusses the application areas of blockchain within the healthcare industry with respect to these properties.

  • Decentralized data management: The data in a blockchain network are dispersed throughout the network; hence no central authority is responsible for managing them or has any superiority over others.
  • Data security and privacy: The data within the blockchain are encrypted first, before making their way into the network, therefore maintaining the data privacy. Furthermore, the data are distributed; therefore, they are very difficult to breach or hack.
  • Data provenance: The data in the blockchain are tracked throughout. From its origin to any modifications, every activity is recorded.
  • Data availability: Every node of the network holds a copy of the data, thus, making it available to everyone at every time.


Use Cases of Blockchain Technology in Various Healthcare Application Domains



EHRs Management




Medical Research

Decentralized data management

Patient-centric model for data management [22].

No fraudulent claims.

No intermediaries [23].

More control over data during transmission and analysis [24].

Data security and privacy

The EHRs are encrypted and only authorized users have the key to decrypt [22].

The confidential details are kept protected [25].

Data sharing while preserving the security and confidentiality [26].

Data provenance

Digital signatures are applied to the EHRs to ensure legitimacy [27].

Insurance is processed only after verification [28].

The provenance provides a base for enhanced and authentic research.

Data availability and system robustness

Distributed network makes the data available to everyone, and difficult to breach or attack [22].

The accessibility of data is ensured anytime, anywhere [25].

The availability of the real-time data that improves the social and medicinal research and also helps in handling medical or natural emergencies [26].

Immutable auditing

A track of all the transactions is kept, and the data on the blockchain cannot be transformed or modified by anyone [29].

Fraud can be detected easily because of the auditing [25].

The data blocks in the blockchain keep a record and are time-stamped, therefore can be easily trailed [30].

Immutability: The data in blockchain network can never be altered by anyone. If any modifications are to be made in the data, a new block is generated instead.

Basic Concepts of Blockchain Technology

Blockchain is a distributed decentralized network that was first introduced as a basic supporting technology for the cryptocurrency named Bitcoin. Blockchain is still in its development phase and is being adopted by almost every industry today. Basically, blockchain is a decentralized network that stores the data in a distributed manner and maintains a log of transactions along with the timestamp and assures that the data are tamperproof. Blockchain is a carrier that stores the information in the form of blocks, and these blocks are connected to one another forming a chain. A block consists of a block header and block body. The headers of the blocks are the most important ones, as they keep the details such as version, header of previous block, timestamp, complexity, Merkle root, etc., along with meta-information such as the structure and usage of the block. The version number of the block defines the validation rules of the set of blocks and the complexity of the block. The Merkle root is created for every transaction and assures the immutability of the transactions. The transactions are signed digitally in order to get the hash value. In a Merkle tree, the root values of the hashes are kept in the blockhead. A block consists of a hash value of its own as well as the hash of the previous block that helps in connecting the blocks in order to form a chain.

The size of a blockchain is fixed, as the number total number of blocks in the blockchain is limited. The first block of the blockchain is called the header block. When a block is generated, the information is first stored in local memory in the body of the block. A Merkle tree is created next within the body of the block that contains the information of the transactions. The root value of the Merkle tree is stored in the root, which is located in the header block. Every block has its own hash value. A cryptographic algorithm is applied to the header of the previous block to get the hash value. This is how each block is connected to the previous one. After getting the hash value, the time is saved in the timestamp field. This is how a blockchain is created. The structure of a block within the blockchain is depicted in Figure 7.5.

• The blockchain infrastructure: Six layers, namely the application layer, contract layer, incentive layer, consensus layer, network layer and data layer, support the blockchain infrastructure as shown in Figure 7.5. Each of the layers has its own purpose in the overall functioning of the network. The bottommost layer is the data layer, that encapsulates the data from the hardware. The technologies in this layer are timestamping, cryptography, etc. This layer deals with the storage and security of the data and ensures the accomplishment of the transactions. The next layer is the network layer that

deals with the interactions among the nodes within the network in peer-to- peer communication, but in a decentralized manner. The consensus layer is the third layer that consists of consensus algorithms. This is the most important layer within the framework, because in a decentralized network like blockchain, the nodes are not trustworthy, and the consensus assures the accuracy of the data. The next layer is the incentive layer that maintains the verification of the entire network by keeping balance among the nodes. It also assures that the accounts are neither destroyed nor tampered with, in order to uphold uninterrupted operation. The smart contract layer is the fifth layer in the blockchain infrastructure that ensures the execution of the transactions without any third-party intervention. The sixth and last layer is the application layer, which supports the tools and technologies required for the implementation of applications. This layer is being adopted by several industries nowadays to build their business applications.

• Transactions in blockchain: There are several types of blockchain frameworks available today, which w'ork differently for distinct applications. Irrespective of the type of system, the working and workflow of the block- chain remain the same. A transaction is the transmission of data from one node to another w'ithin the blockchain network. The transaction is a multi- step process as depicted in Figure 7.6 and the necessary steps are as follows: Step 1: User A requests a transaction. The private key of the previous transaction along with the digital signature is used while asking for the transaction.

Step 2: The transaction is represented in the form of a block.

Step 3: This block of the data is represented to each of the nodes within the network.

Step 4: The nodes validate the transaction by solving some complicated mathematical problems.

Step 5: When the problem is solved, the node displays all the time-stamped transactions of the block to the network. Then the block is checked with respect to the timestamp by all the nodes.

Step 6: This is the final step when the transaction is completed after verification. And the non-verified blocks are invalidated.

• Consensus algorithms in blockchain: The consensus algorithms are processes that help in decision-making for a group of nodes, in which the individual nodes help in making decision for the betterment of the entire network. The algorithm works on trust, where the nodes would make the decisions for the benefit of the group irrespective of their personal profits. The decisions are made on the basis of voting. Fundamentally, the consensus algorithms not only make the decisions on the basis of majority voting, but also agree for the overall welfare of the network. This ensures equality within the online networking. There are several consensus algorithms available today; some of the most widely accepted ones are depicted in Figure 7.7 followed by their brief introduction. Nevertheless, all these algorithms share common objectives, for example:

Seeking agreement: A consensus algorithm must gather as much agreement as possible from the nodes of the group.

Collaboration: The group must work in collaboration with each other to work towards the benefit of the group.

Cooperativeness: The members of the group always put the group first, irrespective their own benefits.

Equal weightage: The group working towards the consensus must assure that every member is equally important, i.e., the value of each and every vote is equivalent.

Inclusiveness: All the member nodes in the network are equally involved in the voting; there is no single authoritative or responsible node.

Participation: In order to successfully achieve the consensus mechanism, all the nodes are supposed to participate.

Proof of work (PoW): It is the first ever proposed consensus algorithm and the most widely used in the blockchain technology. This algorithm works on the idea of solving a mathematical problem. This requires a lot of computations, and the node that solves the problem first gets to the mining of the next block. The mathematical problem could be hashing, integer factorization, tour puzzles, etc. It is effective in handling DDoS attacks. However, using this algorithm leads to the network being computationally complex and growing a lot, leading to the sensitivity of the system.

Proof of stake (PoS): This is the consensus algorithm that overcomes the drawbacks faced with the PoW. However, there is a twist in this algorithm. The blocks are validated before getting added into the blockchain. The individuals who have more coins at stake can be considered as miners and can join the mining. Therefore, if an individual wants to be a miner, he/she would need to have more coins; then only would that person be selected to be a part of the network. Furthermore, after becoming a node of the network, a certain amount of coins is deposited to be qualified as a miner. The processing of this algorithm is quite easy; the number of blocks being generated is equal to the number of coins one possesses, i.e., the more coins a node owns, the more blocks it can mine. Moreover, rewards are given in return for generating these blocks.

Practical Byzantine fault tolerance (PBFT): It is an approach to attain consensus even when some of the nodes are not working properly or not working at all. The main focus here is to protect the system against failures. It makes the decisions collectively including both correct and faulty nodes, hence reducing the error impact on the system. It assumes that there might be a few faulty nodes in the network. The nodes are organized in a particular order, and one of the nodes is selected as the primary node while others are kept as backup. All the nodes work together in sync and communicate with each other to verify all the information available on the network in order to get rid of false information.

Proof of elapsed time (PoET): This algorithm is one of the best among all the consensus algorithms. It works on a permissioned blockchain, in w'hich permissions are required to access the network along with voting and mining rights. In order to assure the smooth running of the network, a secure login for the miners into the system is required using identity validation. It provides a fair chance to every node and follows this sequence: Each of the nodes is supposed to wait for a random amount of time and the one w'ho has had its time share would be allowed to create a new' block. PoET relies on the CPU named Intel Software Guard Extension that runs random pieces of codes on the network and makes sure the processing is fair.

Proof of burn (PoB'): This consensus algorithm is quite remarkable. In this, for keeping the system safe and secure, some of the coins are burnt, i.e., sent to addresses from where they can never be retrieved. Such addresses are called “Eater Addresses,” and the coins burnt can never be used for any purpose; a ledger assures this. However, burning causes loss temporarily but provides trust and commitment in return, w'hich is beneficial in the long run. The miners could burn their native currencies or currencies from other chains depending upon the implementation. It is quite similar to PoW, but the difference is, the power to mine goes to the nodes that have burnt the most coins.

Proof of capacity (PoC'): The PoC is an upgraded version of PoW, in which instead of investing in hardware or burning coins, the miners are supposed to spend on their own hardware, because the selection of the miners in this algorithm is totally dependent on the space on the hard drive available. The larger the sizes of hard drive the more space available to store the solution values. It has more computational capacity, and hence, can create blocks in less time as compared to PoW. It is a tw'o- step process, plotting and mining. In plotting, a list of possible nonce values is generated using hashing, while in mining, a scoop number is calculated by the user, and has to go to that scoop number of first nonce and calculate the deadline value. This is done repeatedly for each and every nonce on the hard drive and the miner selects the minimum deadline amongst them, w'here the deadline denotes the elapsed time duration between tw'o blocks.

Blockchain-Based Infrastructure for Health Information Systems

The blockchain technology is defining the healthcare industry in terms of modelling data and deploying governance. This is because of the capabilities and flexibility provided by this technology in sharing medical data. The blockchain technology has become a centre for the developments in multiple application domains within the healthcare industry. The infrastructure can be divided into four layers as shown in Figure 7.8. The lowest layer is the layer where the raw data are. This is the place where data from IoT devices, medical labs, social media, etc., are collected. These data are

Workflow of blockchain-based healthcare applications

FIGURE 7.8 Workflow of blockchain-based healthcare applications.

heterogeneous and big in nature as the sources are enormous and of various data types. The second layer is the blockchain layer, where the framework for secure healthcare management is created that facilitates the medical data transactions. This layer consists of blockchain-based applications and platforms such as networks, consensus algorithms, peer-to-peer, decentralized, distributed network, etc. The next layer is the application layer, where all these technologies are integrated into a single application. These applications can be categorized as data management, data sharing, R&D, EHRs, handling pharmaceutical supply chains, IoT-enabled telemedicine, etc. The topmost layer of the framework is the stakeholder layer, where the users that are getting benefits from the applications are placed such as businesspersons, patients, researchers, etc. The main interests of this layer are sharing, processing and managing the data effectively without compromising the security and privacy of the data.

Data sharing in blockchain-based HIS: The different application areas within the healthcare domain require different workflows in order to complete specific tasks. The tasks could be as simple as issuing medical prescriptions to as complex as treating the patients witli surgery or complicated procedures. All these tasks require the exchange of information, making the chances of breaches very high. Since the healthcare data are very sensitive, blockchain would assure the privacy and security of the data because of its fundamental features. The following are the different scenarios of

Workflow in issuing medical prescriptions

FIGURE 7.9 Workflow in issuing medical prescriptions.

data exchange within the HIS, and how blockchain could be placed to overcome organizational inefficiencies.

  • Issuing medical prescriptions: The objective of the issuance of medicinal prescriptions is to avoid errors made because of misunderstandings by the doctors and the fraudulent elements within the system. In the HIS, the doctor writes the prescription on the basis of the patient’s diagnosis and stores it as EHR on the blockchain-based network. This EHR can be accessed by the pharmacies via blockchain and the prescribed medicines are issued along with the dosage details. The data interactions in such transactions are amongst doctors, patients and pharmacies as shown in Figure 7.9.
  • Sharing pathology reports: The main aim here is to allow pathological labs, doctors and other stakeholders to share information about the patient’s medical lab results as shown in Figure 7.10. When the reports of the patient’s tests are available, they are notified, and the records are saved on the block- chain-based network so that appropriate treatment can be provided. Having the lab records on the blockchain eliminates the need to carry them everywhere as these documents can be accessed anytime anywhere; this also reduces the cost of printing, faxing and management.
Workflow in reimbursement of healthcare services

FIGURE 7.11 Workflow in reimbursement of healthcare services.

Reimbursement of healthcare services: The focus here is to accelerate the process of reimbursement and to catch fraudulent claims. Using the blockchain-based network would reduce the probability of errors and misinterpretations. The insurance providers transfer their insurance policies and guidelines over the blockchain network, and other users such as healthcare providers, pharmacies and laboratories work for the verification of the claims made by the patient as can be seen in Figure 7.11. Digital verification using blockchain would save time, manual efforts and costs for the customer, while doctors w'ould start treatment without waiting for confirmation, as everything is transparent. It enables the patients and doctors to customize the treatment and insurance respectively.


Data are the most important asset to the healthcare industry; and the HIS are designed to manage these data efficiently. This provides several benefits like cost and time saving, organized treatment, patient satisfaction, proper circumvention of medicines, etc. There could be several types of HIS depending upon the user requirement. The main focus in implementing the HIS is the security and privacy of the data that must be ensured during the life cycle of the data using various scientific practices. The healthcare data available today are in various formats coming from diverse sources like laboratories, healthcare providers, insurance and pharmaceutical companies, etc. Moreover, there is no standardized way of keeping the records, which might lead to infringement and chaos in the system. Furthermore, the unavailability of safe and secure infrastructure has also obstructed development in research and development processes.

The blockchain has gained noteworthy attention from various types of organizations. It offers features like decentralized architecture, immutable auditability, availability, security, privacy and provenance, and has the capability to transform the face of the healthcare industry entirely at a very low cost as compared to traditional systems. It has its use cases in managing EHRs, handling health insurance, issuing medicines from pharmacies, research for public benefits, etc. The blockchain uses the concept of consensus algorithms for successful implementation. These algorithms assure unbiased decision making for the benefit of the entire network. The data-sharing processes in blockchain-based HIS are more secure and transparent. Moreover, using blockchain-based infrastructure would empower the patients whilst maintaining the security and privacy of the data and providing quality healthcare services.


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