Blockchain based system to store and retrieve healthcare records

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 09 Issue: 04 | Apr 2022 www.irjet.net p-ISSN: 2395-0072
© 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 2640
Blockchain based system to store and retrieve healthcare records
Aditya Singh1, Akash Salvi2, Kaushal Pawar3, Aayush Prabhu4,
Dnyaneshwar Bavkar5
1,2,3,4Computer Engineering, Terna Engineering College, Nerul, Maharashtra, India
5Assistant Professor, Dept. of Computer Engineering, Terna Engineering College, Nerul, Maharashtra, India
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Abstract - Blockchain technology and its use case domains
are growing rapidly due to the features and benefits offered
over the existing systems. These features include
decentralization, immutability, complete transparency, faster
traceability, enhanced security and trust, automation without
human involvement, and increased efficiency and speeds.
These features are beneficial to many industries including
supply chains, banking and financial sector, healthcare and
pharmaceutical sector, governments, and insurance
companies. The handling of patient records has been a
recurrent issue in the healthcare sector as it is difficult to
implement the right privacy and security measures in the
existing systems. Data breaches, cyber-attacks, and identity
theft are major threats in today's digital environment, and
existing solutions have proven ineffective at managing these
challenges. The threat of a single point of failure also looms
over the existing centralized systems. Our research intends to
address concerns with existing systems for accessing,
managing, and securing health record data and offer a
blockchain-based alternative for storingandretrievinghealth
information. Ethereum blockchain platform is used to
implement the data structure of our system. We also discuss
the trade-offs in the adoption of blockchain technology.
Key Words: Blockchain, Solidity, IPFS, Healthcare,Smart
Contracts, Ethereum, Decentralization, Secure
transactions, Transparency
1. INTRODUCTION
In recent years, medical practices have grown in
prominence, with the primary goal of addressing ways to
improve an individual's quality of life. In this data-driven
environment, information systems are also becoming more
important, as they can improve access to healthcare and
business. Users can easily access their data thanks to the
rapid development of technologies like informationsystems
and cloud computing. Users are more than often connected
to the internet with all the information they require being a
click away. The traditional healthcaresystemismoredoctor-
centric. All the medical reports are stored by the healthcare
institutions or medical professionals in the form of physical
or digital files. Theseinstitutionsusea centralizedrepository
for storage which could become a cause for concern in
maintaining privacy, accessibility, and security.
1.1 Reason to use Decentralization
In the health record management system, information from
multiple sources like prescriptions, medical prognosis, and
scans. This type of sensitive information is critical to
patients’ treatment. Currently, physical file repositories and
centralized databases are used to store this critical
information. These methods are prone to a single point of
failure issue. Another issue is the inter-accessibility of these
records as a patient may visit multiple doctors in different
medical institutions and it may not be possible for two
different entities to share the patientrecords.Thesesystems
should also be tamper-proof andonlyauthorizedindividuals
should be able to access and change the records. The
authorized individuals are usually from medical institutions
but this becomes are privacy and security issue individuals
are prone to errors. Maintaining a timelineofreportsisquite
difficult to achieve in these systems. A personal ledger could
maintain a timeline of reports which would streamline the
process of diagnosis.
1.2 Advantages of Blockchain Solution
The proposed solution to these problems is a blockchain-
based electronichealthrecordsystem.Ablockchainprovides
features that could solve the existing issues in the health
record systems. The proposed system is user-centric and
decentralized which also means no single institution is in
charge of maintaining the system. A blockchain is a public
database this is up to date and shared throughout many
computer systems in a community. This increases the
accessibility and transparency of the system. Inthepersonal
blockchain, the best recognized and identifiable set of
members are explicitly admitted to the blockchain
community. This reduces the presence of maliciousactorsin
the community. As the data are saved in a blockchain that's
programmed to be permissioned, the information may be
very secure and guarded against any tries to tamper with it.
The information may be decentralized and could allow the
person to clean and rapidly get the right of entry to their
personal information. The blockchain couldbeverystablein
storing healthcare personal files due to the fact if a person
attempts to tamper with one block, all of the different
determine blocks need to be modified for this reason and
comply with this. Hacking a blockchain community isn't any
clean task, it requires tremendous computational electricity
that can fail if the information itself is encrypted. Hence the
proposed system can provide a viable solution for storing
the health records of a patient.

2. PROBLEMS WITH CURRENT SYSTEM
The current system of sharingmedical recordsisassuchthat
they are feasible and compatible within a specific institution
only. They can use their private networks in which the
patient documents can be circulated between different
departments. But this situation is not always ideal as a
patient does have unexpectedly changing behavior when it
comes to their health. It becomes a crucial necessity that
such reports are interoperable and formats understood by
multiple institutions participating in the medical lifecycle of
a patient. Presently major of healthcare data depends on the
interaction between the medical profession and the patient,
and less importance is given to the data analysis part for the
diagnosis. This makes such procedureslonganddifficultand
is not welcoming to the patient. The presence of a
complicated medical onboarding process also discourages
the participation or active check-ups by people who then
reach out to inexperienced and unprofessional opinions.
The amount of data generated related to healthcare is
massive and needs proper collection and management.
Patients have multiple doctors and physicians and the
medical reports are scattered and non-standardized. In
current systems, the medical reports rely on doctor-patient
interactions, and these reports are scatteredacrossdifferent
systems making the data less secure and less reliable. Even
now in some cases, medical institutions use handwritten
reports and physical files for managing patient data. This
method of data management is very unreliable as human
mistakes happen while forming reports and files could be
lost and misplaced in poorly managed file repositories.
Proper and truthful record keeping is required along with
compatibility of data across different systems.
3. RELATED WORK
A whitepaper in early2009,thenotionof blockchain
began to garner public interest, resulting in the first
extensive applicationofblockchain,a digital currencyknown
as Bitcoin[1]. They envisioned an online transactional
system that would allow users to send digital currencies to
one another without the requirement of a financial
intermediary. Peer-to-peer transactions enable
decentralization, and all transactions are cryptographically
hashed to provide high levels of security.All transactionsare
recorded on a distributed ledger network, which ensures
that they are transparent.
Many blockchain-based platforms for decentralized
applications began to emerge as thepopularityofblockchain
technology and its possible uses expanded,oneofwhichwas
Ethereum[2]. Due to the rapid development enabled by
blockchain platforms like Ethereum, the applications of
blockchain beyond digital currency are diverse and ever-
growing.
An electronic medical record system that makes the use of
Inter Planetary File System to store and retrieve data with
corresponding hash and encrypted data for decentralization
and the encrypted keyword information of the medical data
is stored on the Ethereum blockchain[3]. This method of
storage helps reduce the load on the blockchain as high-
frequency access can be stressful. It ismuchmoreefficientin
terms of the resources used to store such large amount of
data in Inter Planetary File System instead of the blocks in
the blockchain, as the medical data can have large sized files
for which a blockchain is not suitable as a storage service,
instead it should be used for recording the transactions and
file locations[4].
To mitigate the raised privacy concerns in existing and
centralized health record systems and the need for privacy
mechanisms in health record systems, blockchain due to its
immutability and irreversibility is a potential solution for
incorporating privacy and security in health record systems
but it also comes with its drawbacks[5].
Proposals for a private blockchain based on the Ethereum
protocol, where sensors communicate with smart devices
which invokes the smart contracts that write records on the
blockchain were made[6]. This provides real-time patient
monitoring and keeps a secure record of patients’ data. This
also resolves the security problems related to sending
notifications to the patient in a HIPAA-compliant manner.
It becomes important for the patient to have the access
control over their health records. Suchproposalsweremade
to use an Ethereum blockchain solution that will use smart
contracts to ensure the trustful and secure access of data by
the patient and other concerned entities involved with the
treatment[7].
There are already conducted systematic reviews of
blockchain technology applications in the healthcare
industry. In conclusion, a large number of healthcare
application prototypes are being developed using the
blockchain platform, and the number of publications in this
field has increased in recent years. Blockchain is still a field
in which more research is needed to determine its utility in
healthcare[8]. For a better use of the blockchain storage
structure which provides the advantage of immutability, it
can store the metadata of the files and of the stored medical
data whereas the medical data files itself can be stored with
the help of Distributed Hash Tables as it offers decentralized
storage and distributive processing[9].
There are some limitations which are identified in this
solution for storing the records in such applications. It
includes the cost-effectiveimplementationofprocessingand
storing data which will be on the chain and issues regarding
the scaling of the blockchain system even on a public
ledger[10].

4. BACKGROUND
4.1 Blockchain Cryptography
The concept of blockchain revolves around the system of
Distributed Ledger technology. It is a decentralized growing
chain of blocks that are linked together. The new blockchain
architecture is a peer-to-peer network that was introduced
with Bitcoin in 2008. Programmatically these cryptographic
functions are called Hash functions. Such functions aim to
take the input of arbitrary length and generate an output of
fixed length. There are different types ofhashfunctionsused
in different blockchain architectures. Forinstance,tomakea
collision-resistant cryptographic hash function Merkle–
Damgård hash function is used. A practical example of such
will be the SHA-256 used for Bitcoin. Another way is using
Sponge construction, and the example would be SHA-3 used
for Ethereum.
The ledger in a blockchain can be replicated andmaintained.
In an event where one copy is edited, it should trigger a
chain reaction that causes the other copies to update
simultaneously[11]. This eliminates the requirement for
anyone else to validate if the transaction occurred or not.
4.2 Blockchain structure and transactions
The purpose of the development of the blockchain would be
about developing a trust less system where we can program
our ethical and legal practices in the smart contract and
store the rules of operation on the ledger. This will help to
mitigate the doubt of human error in following the code of
conduct and ethics while interacting with the system as
everyone will have to come to a common consensus. These
problems are countered when a certain practice has the
support of a large population and is peer-reviewed.
Blockchain ultimately refers to a chain of connected blocks
that stores informationaboutall theactionsandtransactions
that are occurring on the network on which the blockchain
exists. It will contain information on current transactions
and the history of occurred transactions as well[12]. Each
block is linked to the previous one by a hash code, which
may be generated by the algorithms used by the platform,
some of which are discussed above, and a new block
becomes a part of this chain as soon as it is created.
Blockchain networks can use public key infrastructure,such
as Bitcoin, which uses the users' private and public key
addresses to authenticate the user from their network-
connected wallets. All information blocks are stored in disc
space called nodes, which keep records of all network
transactions and check the authenticity of any occurring
transaction [13].
The transactions in the networks are chained with the
previous block transactions using the hash of the preceding
block, and this achieves the blockchain'simmutability[14].If
an attacker tampers with the information stored in the
blocks over the network, the local copiesofthe blockswill no
longer be validated because the linking bridge, which is the
hash code, will be changed upon the execution of any
transaction on the chain by the hash function. In a further
development of the technology blockchain, second-
generation or blockchain 2.0 uses the concepts of smart
contracts which are just scripts of a code that can execute
itself upon fulfilment of a condition. It is helpful in domains
of ownership, sharing data, and maintaining digital
signatures. Blockchain uses the consensus mechanism to
agree on the true state of a node.
Fig -1: Blockchain structure
Fig -2: Block details
5. PROPOSED SOLUTION
5.1 Storing Data on Blockchain
When data is added to the blockchain, it is encrypted,
making it immutable and difficult to decipher. It authorizes
transactions using a personal identification key known only
to the user. As a result, unlike current healthcare data
technology, a healthcare provider would only be able to
access a patient's medical data if they had explicit access to
the blockchain record. Blockchain technology can keep
patient information safe and secure while allowing them to
share it with any service provider of their choice. It ensures
the authenticity of anti-counterfeiting techniques and
provides proof of ownership of medical records.
Users’ signature is used to ensure the validity of the health
data stored. All healthcare metadata can be storedina single
block for a particular patient. Generally, the blockchains are
not suitable for storing large data files such as images or
report files which can accompany the rest of the data. So, to
overcome this a cloud storage system stores the data files
and on the blockchain we can store the corresponding hash
values or metadata pointing to the access of a particular file.
5.2 System Architecture
When the new data is created, a hash value will becalculated
corresponding to the generated or uploaded data. We will
use the hash algorithm called SHA-2. With the public key of

the owner to ensure the confidentiality of the records,
metadata of the data is generated. This will help us to
develop a search functionality which can be used to map the
data files which will be stored in the cloud so that users with
certain permissions can access those files just with the
metadata which points to the file on cloud. This way we do
not need to store the massive files on the chain which first of
all it is not optimized for and saves a lot of additional
changing of datatypes. Keys are provided to the person who
has the permission to access these files. Afterthe recordfiles
are stored on the cloud, its mapped hash value is taken and
mapped to a generated id unique to the associated data with
the hash value. A signature is generated for this data and
then the metadata, hash values, ids and owners public
address are stored in a block and appended to the
blockchain network.
The use is able to get the access information of the health
records from the metadata stored in the blockchain which is
associated with a data file on the cloud. Using the users’
signature to check the authenticity of the request and
allowed permissions and decrypts the data on the cloud,
effectively giving the access to the requesting user.
Fig -3: Data flow diagram
5.3 Development Methodology
We layout a decentralized accessed framework with the use
of permissioned blockchain generation with Ethereum for
Health and medical data. It eliminates the critical
dependence on centralized computing assets for storing,
processing and gaining access. The ensuing structure can
assist in growing and promote sustainableimplementations.
In the system there will be multiple datatypes which can
store the essential information and provided certain access
to other parts of the system. We create the data structure for
storing the doctor’sinformation,patients’information which
includes the byte array of files where the hashes of the
records will be stored for a patient. Next, we also have the
address or public key array corresponding to the doctor’s
profile in the patient structure. Similarly, the doctor’s
structure will have an address array which will contain the
patient private keys so for the doctor to use. The file
structure will contain certain fields such as file name, type,
hash and the metadata will be stored in the additional
information about a file.
We map the address or the public key of the patient to its
corresponding doctor structure profile who is currently
diagnosing the patient. Another mapping is made which
maps a byte32 datatype which will be the hash value of a file
uploaded to the “filesInfo” data structure which containsthe
metadata of the file records. Some more mappings are
present in the contract which maps the public keys of the
user to the permissions of access to files. In the contract we
first execute a constructor where the owner addressissetto
the address which is currently executing the contract.
Using modifiers, we verify if the user is a registered doctor
or a registered patient or if the user has access to the file or
not and some functions which can only be executed by the
owner of the contract. They are helpful in checking if a
function is being executed by the right typeofuserorifsome
predefined conditions must be checked before moving on.
The contract provides the functionality to sign up a patient
and a doctor. It can provide certain access to the doctor for
the files. The contract allows the patients to upload files
which are essential and required for the medical services.
These functions are called transactional functions as when
such functions are executed by the user calling the contract,
the state of the contract is changed which causes the
generation of a new block in the chain. Before saving the
block, it has to be verified on the chain. This is done by using
the proof of stake concept used in blockchain transactions.
It is consensus model which allows the updating the blocks
in the chain securely. In Ethereum we can use the Proof of
stake model for multiple users to reach a consensus on a
particular transaction which makes it valid.POSalgorithm is
a development over the proof of work mechanism which
does have high-cost implications.
The contract can be used to check profiles of a patient or
doctor. Whenever the contract state changes in any way, a
new block is created. Some functions do not need to change
the state of the current contract and hence there is no
transactions performed upon calling such functions on the
contract. In the client side the user is givemultipleoptionsto
check the permission level and accessed files via such call
function on the contract like getting the file infofora patient,
doctor information. While adding a filefora patient,thehash
is returned using the data collected from the clientsideas an

input. Keccak256 is a built-in cryptographic function I
Solidity, it will take any number of inputs and convert it into
a 32-byte hash. This is an irreversible operation as you
cannot regain the original data by converting the hash value
to the original string or byte array of data. The algorithm is
designed in such a way to prevent it from happening and
breaching the privacy of users.
Fig -4: Entity Relationship Diagram
6. CONCLUSIONS
In this paper a blockchain based solution is approached for
upgrading the current existing methods for storing and
accessing the electronic healthcare records. The proposed
solution considers the requirements of the health record
systems and the loopholes centralized systems which are in
practice. Heavy consideration is given to preserve the
privacy of the health records according to medical practices
followed and mentioned in associated research papers. A
good quality system for storing the records which provides
the non-tampering architecture and restricted access based
on the permissions given to different parties is required
where personal information is constantly under threat.
Other requirements which pushed the development of such
systems are the limited storage, synchronizing the medical
records for multiple entities involved such as labs,
pharmacies, hospitals, private medical professionals etc.,
Keeping the clear transaction logs for every change in the
data to improve transparency of the system, and avoiding a
central point of failure using a decentralized system.
REFERENCES
[1] Satoshi Nakamoto, 2008, "Bitcoin: A Peer-to-Peer
Electronic Cash System" .
[2] Vitalik Buterin, 2014, “A NEXT GENERATION SMART
CONTRACT & DECENTRALIZED APPLICATION
PLATFORM”, Ethereum White Paper .
[3] Sun J, Ren L, Wang S, Yao X, 2020, “A blockchain-based
framework for electronic medical records sharing with
fine-grained access control”, PLoS ONE 15(10):
e0239946.
[4] Ayesh Shahnaz, Usman Qamar, Ayesha Khalid, 2019.
"Using Blockchain for Electronic Health Records", IEEE
Access, Digital Object Identifier
10.1109/ACCESS.2019.2946373.
[5] Thein Than Thwin, Sangsuree Vasupongayya, 2019,
"Blockchain-Based Access Control Model to Preserve
Privacy for Personal Health Record Systems", Hindawi
Security and Communication Networks Volume 2019,
Article ID 8315614.
[6] Kristen N. Griggs, Olya Ossipova, Christopher P.Kohlios,
Alessandro N. Baccarini, Emily A. Howson, Thaier
Hayajneh, 2018. "Healthcare Blockchain System Using
Smart Contracts for Secure Automated Remote Patient
Monitoring", Mobile & Wireless Health.
[7] Mohammad Moussa Madine, Ammar Ayman Battah,
Ibrar Yaqoob, Khaled Salah, Raja Jayaraman, Yousof Al-
Hammadi, Sasa Pesic, Samer Ellahham, 2020,
"Blockchain for Giving Patients Control Over Their
Medical Records", IEEE Access Volume 8, 193102-
193115
[8] Cornelius C. Agbo, Qusay H. Mahmoud and J. Mikael
Eklund, 2019. "Blockchain Technology in Healthcare: A
Systematic Review", Healthcare 2019, 7, 56;
doi:10.3390/healthcare7020056.
[9] Saqib Ali, Guojun Wang, Bebo White, Roger Leslie
Cottrell, 2018,"A Blockchain-based Decentralized Data
Storage and Access Framework for PingER", 2018 17th
IEEE International Conference On Trust, Security And
Privacy In Computing And Communications/ 12th IEEE
International Conference On Big Data Science And
Engineering.
[10] Suveen Angraal, Harlan M. Krumholz, Wade L. Schulz,
2017. "Blockchain Technology Applications in Health
Care", American Heart Association, Inc., DOI:
10.1161/CIRCOUTCOMES.117.003800.
[11] Iansiti M, Lakhani K, 2017, “The truthaboutblockchain”,
Harvard Business Review, 2017 Jan–Feb.
[12] Khatoon, A.; Verma, P.; Southernwood, J.; Massey, B.;
Corcoran, P. “Blockchain in Energy Efficiency”:Potential
Applications and Benefits. Energies 2019, 12, 3317
[13] Yli-Huumo, J.; Ko, D.; Choi, S.; Park, S.; Smolander, K.
“Where is current researchonblockchaintechnology?—
A systematic review”: PLoS ONE 2016, 11, e0163477
[14] Baliga, Arati. "Understanding blockchain consensus
models." Persistent 4 (2017): 1-14.

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