Keywords

1 Introduction

As it is known that in medical industry, ample amount of data is generated meaning thereby healthcare system is data-intensive systems where data is circulated and accessed by different hospital, health centers, laboratory, medical management units. Now, digitization in healthcare industry is taking place resulting in development of healthcare information systems. Health care is an essential part of one’s life so its data too as it helps in diagnosis of disease supporting proceedings for future reference. In old times, data was written and recorded which can be tempered and damaged effortlessly [1, 2]. There is a need to protect data arise. Thus, emerging technology came into view that is blockchain technology which promises to secure data from vulnerabilities and protect data leakage. If use with cloud computing, issue regarding to storage can be solved as it is most reliable method for management of data. Nevertheless, numerous security issues can be addressed while using blockchain-based cloud computing [3]. Basic architecture of blockchain is illustrated in Fig. 1.

Fig. 1
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Blockchain architecture

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Nakamoto [4], a report by Nakamoto concept of blockchain technology is introduced that amend challenges cryptocurrencies are facing. Author introduced technology for secure transaction. As blockchain technology insures genuineness, accountability, validity, anonymity and uprightness, it is preferred for securely sharing and hoarding information. Author proposed which promises confidentiality, answerability and validation for sharing of data. Proposed system considers public health authorities, researchers and blockchain miners. For preserving autonomy of information, cloud environment with blockchain is incorporated. Only verified users can access the system. All activities of users are monitored for purpose of answerability. For sharing of information, cryptographic techniques are used.

Li et al. [5], authors convey healthcare data is very essential for every individual and it storage too. The cause of concern is data vulnerability to theft, which can result in wrong diagnosis and mishap of revenue. Author proposes blockchain-based framework that authenticates storing of data effectively by using cryptographic techniques. Ethereum is a platform on which system is proposed as it sets out high accuracy of results. Proposed system assures security and privacy of data, and many users want their data to get stored in this architecture. As new patient arises, a novel fragment is created and every block has timestamp that gets authenticated by cryptographic mechanism and has hash data of prior fragment. Data is closely monitor so that there is no unauthorized access. Proposed system has minimum risk to healthcare information as method used for recording of data is tamper proof.

Blockchain technology is distributed ledger technology with decentralized database management for multiple users and transaction. They are recorded with cryptographic signature know as hash. Thus, this technology can tolerate failure efficaciously [6]. Rest of the paper is organized as follows: Discussion is made on blockchain in health care in Sect. 2 with emphasis on its features in health care. Section 3 presents review of previously done work along with a review of some state-of-the-art blockchain-based healthcare systems. Section 4 discusses challenges faced by blockchain in health care, and lastly, work is summarized in Sect. 5.

2 Blockchain in Health Care

Presently, information of patients is being recorded electronically making use of electronic health record (HER), to diagnose a disease for further investigation. These healthcare records are being exchanged among various hospitals and health centers, but sometimes hospitals do not want to share data which results in data or information blockage, another threat in breach of privacy as it can be accessed. Thereupon, an approach came up as preserver known as blockchain to address issues like security and privacy of information which guarantees anonymity, confidentiality and accountability of records. Figure 2 shows features that would help in achieving security and privacy of blockchain in health care.

Fig. 2
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Features of blockchain

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Thus, features of blockchain can be summarized as follows [1, 7, 8]:

  1. 1.

    Decentralized—It is maintained by group of nodes where there is no governing authority. One can directly access data by using private key.

  2. 2.

    Enhanced Security—With the help of encryption technique, security of data is promised and information is hashed by hiding true content

  3. 3.

    Distributed Ledger—It uses nodes for storage of data so there exists ownership of data.

  4. 4.

    Autonomous—In blockchain, data is transferred and updated securely.

  5. 5.

    Immutable—Records in blockchain are immutable as they cannot be altered.

  6. 6.

    Consensus—Blockchain goes well with consensus algorithms; it helps network to make decision for the nodes that are registered on the platform.

3 Related Work

Health care is a complicated sector where ample amount of information is being generated, stored and shared on daily basis. Healthcare industry is having excessive resonance in terms of profit and information creation. As healthcare industry is expanding, there is an urge to secure data. With enormous amount of electronic health records (HER), invulnerability of information is the necessity of time. In today’s time, data of patients is gradually shifting toward cloud repository. For making private data more certain, blockchain technology is impulse. In this section, discussion is being made upon blockchain-based health care with emphasizing on security and privacy of data [1]. Authors in Azaria et al. [9] put forward that in today’s digital world, security and privacy of patient’s data in healthcare industry are of at most important and the same needs to be stored in a digitized form. This can be done by employing blockchain technology to oversee healthcare data. This will help in achieving ultimate target of genuineness, answerability and assurance for data sharing which is required. Best suitable and flexible architecture is proposed to integrate information with regional and existing data storage. Proposed system guarantees secure access to medical records of patients with assuring them if any changes are done they are aware of it. Proper validation of credentials is done to check upon which blockchain minor has access to which data. Decentralization of medical records are put forward in secure way. Framework used is smart contact mechanism, and POW-based consensus algorithm is used to authenticate novel block in system. Recommended safety aspect of blockchain in health care is shown in Figure 3.

Fig. 3
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Blockchain aspect of safety in health care

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The works presented in Xia et al. [10] propound that privacy of healthcare data is utmost priority as it jeopardizes to violate patients’ state. If infringement occurs, it will give negative impact on all the patients, stakeholders and miners. To overcome this situation, authors proposed blockchain-based technology framework to protect the liberty of data using cloud computing. Only verified users can have right to approach system. Cryptographic techniques are used for sharing of patient’s details. So, it acts as a mediator between end user and radical medical data. Substantial blockchain has been suggested for swift transaction and actual competence. Three layers have been suggested by authors; they are user layer, system management layer and storage layer. The user layer comprises of data miners who want to entreat data. In system management layer, all connections are fixed for firm deal. Rearmost layer, i.e., storage layer, contains complete details which will set aside on cloud for further various applications. Dubovitskaya et al. [11], authors feel that healthcare data is immensely delicate and seldom the information required to conjunct with shareholders for exceptional motive. For this, blockchain-based health management system is proposed that guarantees accountability, confidentiality and lucidity of data. This architecture delineates for cancer-affected patients. The model ensures invulnerability of data, and time required for sharing of data is minimal. For storage of data, membership service databases is preferred that verifies blockchain face workers to ingress blockchain system. Uninterrupted data is stored on two databases that is local database and cloud server. The confined database holds cancer data, and cloud server holds unqualified information. All of execution appraisal by researchers is based on secrecy, certainty and extensibility. Work presented in Esposito et al. [12] shows that healthcare data is shifting to cloud services and is vulnerable to threats. For security and privacy of healthcare data, blockchain technology is proposed. In given system, it is identified who is the patient and how data is kept in blockchain technology. When a new patient is added, new block is attached to the structure. Blocks consist of distributed and decentralized network. Each block in existence blockchain has timestamp that gets verified with cryptographic techniques with hash details of prior block. Patients can directly access their data, and if any unlawful interference occurs, they get recognized effortlessly. Al Omar et al. [13], authors are of the opinion that cyber aggressor has interest in healthcare data as enormous revenue is involved. Author believes decentralized data can be secured effectively. For this purpose, healthcare data management system is integrated using blockchain technology as integrity and accountability are guaranteed. Privacy is ensured by using different cryptographic mechanism. It also checks information given by patient is lawful or not. The data receiver layer first authenticates system only after that data is received from end user. All the testimonials are stored by registration unit in which novel end user access data from system. Information like password, specifications, private information of users are generated. After providing information one time, the user gets access through secured channel for transaction. The parties interact and exchange of information takes place by private accessible unit where secured transaction took place. In this, an arbitrator serves as a bridge between user and tactful information put down in subsist blockchain. In this blockchain technology, revert an identifier which assists user to approach the information. Kaur et al. [14], authors specify there is intense need to store healthcare data securely as the same is utmost importance being data heterogeneous in nature. So, they came up with idea of integrating blockchain with cloud computing as this platform is able to manage vast medical data very swiftly, thus guarantees security of information. In today’s time, data is stored on centralized servers, but authors put forward decentralization thus incrementing interoperability. Files are stored in the form of fragments, so if any transaction occurs, it gets stored over different node and identification of user is done through cryptographic mechanism. Once verification process is completed, a new fragment is added about the deal and user gets permission to information access. Xia et al. [15], authors proposed structure, namely MeDShare that promises genuineness, answerability and efficacy of medical data using cloud storage as malicious activities which can cause damage to revenues that are generated by healthcare data, since current privacy policies are not that secure. In proposed system, data is secured in fiddle around manner by this healthcare data at minimum risk. Proposed method has four layers; they are user layer, data query layer, data provenance and structuring layer, lastly existing database infrastructure layer. First layer comprises blockchain miner as they want to access data to make transaction. Second layer processes and carry out queries generated by miners. Third layer consists of components likely authenticator, processing and consensus, contact, smart contracts permissioned database and blockchain network. The hindmost layer consists of all previous data. Uddin et al. [16], authors put forward blockchain-based framework for remote patients in healthcare environment in which they suggest that every single patient should have wearable devices so that their health data is monitored and information get stow in blockchain after computing. Fragments are built with the help of miner mechanics, and it diverges from existing bitcoin-based miner concept. In the proposed system, hash value of current block is generated by single minor which was not possible in bitcoin-based miner concept. Selection of miner is based on some feature extraction together with patient centric model for enduring patient information, but there is lack of proficiency as to how validation is done for block and authentication method is not completely probed. Table 1 summarizes some state of the art blockchain-based EHR work.

Table 1 State-of-the-art blockchain-based EHR systems
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4 Challenges Faced by Blockchain Healthcare

Recent researches are concerned on employing blockchain technology in medical field i.e. healthcare to resolve issues related to trust, security and privacy of medical records but certain research opportunities and challenges need to be addressed for gradually shifting from old method of recording data to blockchain-based electronic health record (EHR) system [25].

  1. 1.

    It would take a major cultural shift—Still, many doctors prefer to save record of patient on paper, asking them to shift on electronic mode that is electronic healthcare record (EHR) is a fact to ponder upon. Changing behavior of how people work in any industry is a big task.

  2. 2.

    Health care is distributed so it is hard to implement—It is tough for single user to access all the attributes altogether to adopt blockchain environment. If not adopted, practicality of system decreases.

  3. 3.

    Some players are not willing to share—Data which can lead to generation of revenue is kept private in organization, and if they are forced to share data with insurance companies, they get different quotations for different patients. Thus, it is very difficult to share data when it is for profit.

  4. 4.

    There is nothing proven yet—As there is no proven use-case healthcare professionals are not willing to adopt this technology and are not ready to work on the solution so that patient’s data can be stored securely and in efficacious way.

5 Conclusion

Blockchain keeps track of all the data and the information shared over Internet. It promised invulnerability as one has to pass through different layer of security. If any unauthorized access is recognized by the system, it will block the network to safeguard the data. Sharing of information is secure as it is transparent and decentralized in nature. Blockchain rigorously protects information of patients. This paper put forwards review of previously done work using blockchain based technology for health care along with security and privacy issues in blockchain. Several state of the arts on blockchain-gleaned electronic health record (EHRS) system have been addressed with the motive to secure data from intruders. The need of the hour is to identify some effective methods of maintaining security and privacy of data which shall be identified and proposed in future work.