A Comprehensive Blockchain-Based Architecture for Healthcare Systems

Jos

e Victor Marques dos Reis Melo, Inaldo Capistrano Costa

, Juliana de Melo Bezerra

and Celso Massaki Hirata

Department of Computing Science, Instituto Tecnol

ogico de Aeron

autica (ITA), S

ao Jos

e dos Campos, Brazil

Keywords:

Blockchain, Healthcare Systems, Software Architecture, Smart Contract, Medical Records.

Abstract:

Blockchain technology has emerged as a versatile solution with wide-ranging applications across various in-

dustries, including healthcare. The increasing number of breaches in medical records in health systems high-

lights the imperative for innovative solutions. This paper delves into the potential of blockchain to improve

information management in healthcare systems, considering data privacy, cybersecurity, and reliability con-

cerns. We propose a blockchain-based architecture that takes into account key entities of healthcare systems,

such as patients, physicians, diagnostic centers, and pharmacies, and facilitates their transactions through the

use of blockchain technology. Through comprehensive sequence diagrams, we illustrate the orchestrated in-

teractions among selected entities. The paper presents a proof of concept implementation, providing details on

application development, smart contract speciﬁcations facilitating seamless information sharing, and the tests

conducted. The implementation of the blockchain-based architecture and sequence diagrams was successfully

tested. We conclude that the proposed architecture enables the improvement of the data privacy of entities,

the cybersecurity of data sharing among diverse entities, and the reliability of transactions within healthcare

systems.

1 INTRODUCTION

From the evolution of enabling technologies for

various industries over the years (Mubarok, 2020),

blockchain has emerged as a versatile technique

with wide-ranging applications across different sec-

tors (Javaid et al., 2021), including the healthcare

domain, educational services, logistics and transport,

and government domain. The focus of blockchain

technology has been on fostering innovation within

these domains.

Nowadays, healthcare systems face various chal-

lenges, particularly addressing concerns related to cy-

bersecurity, data privacy, and reliability. The escalat-

ing number of breaches in medical records over the

years (HIIPA Journal, 2021) underscores the impera-

tive for health organizations to address these concerns

with heightened responsibility.

Numerous scandals have unfolded involving the

leakage of healthcare data. In 2018, there was a

personal data breach affecting 1.5 million patients

in Singapore (Davis, 2019b). In 2021, patient data

https://orcid.org/0000-0002-0141-0736

https://orcid.org/0000-0003-4456-8565

https://orcid.org/0000-0002-9746-7605

from multiple providers was illicitly obtained and

subsequently leaked on the data repository GitHub

(Davis, 2021). Notably, only a small percentage of

healthcare data breaches compromise sensitive medi-

cal data, such as diagnoses, while the majority (almost

70%) exposes patients to the risk of identity theft and

fraud by hackers (Davis, 2019a).

The issue of privacy becomes increasingly rele-

vant, given the growing market demand for access and

sharing of personal data (Pauletto, 2021). This often

occurs without the data owner having full control over

their information, as the mechanisms for data shar-

ing and handling are currently not transparent. Con-

sequently, data subjects frequently ﬁnd themselves in

a vulnerable situation.

The concern for data protection has been height-

ened in recent years with the enactment of laws that

restrict the use and sharing of data by organizations,

exempliﬁed by the General Data Protection Regu-

lation (GDPR) in European countries and the Gen-

eral Personal Data Protection Law (LGPD) in Brazil.

These laws grant greater autonomy and control to the

data owner, imposing sanctions for inappropriate use

and sharing by organizations. Despite the existence of

such laws, many organizations disregard these mea-

sures (Magalhaes and Oliveira, 2021).

250

Melo, J., Costa, I., Bezerra, J. and Hirata, C.

A Comprehensive Blockchain-Based Architecture for Healthcare Systems.

DOI: 10.5220/0012616400003690

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 26th International Conference on Enterprise Information Systems (ICEIS 2024) - Volume 1, pages 250-257

ISBN: 978-989-758-692-7; ISSN: 2184-4992

Moreover, there are challenges in the relation-

ships among the various entities involved in health-

care. With numerous entities participating and limited

data sharing among them or their respective organi-

zations, challenges arise, such as facilitating the efﬁ-

cient and secure collection of a patient’s medical data

by other healthcare entities or enhancing the commu-

nication of data between physicians and patients, as

discussed in the article (Shen et al., 2019). Aligning

the need for data sharing between different healthcare

entities with patients’ demands for data protection is

a notable challenge.

We propose a blockchain-based architecture that

orchestrates interactions among the key entities in

healthcare systems. We delineate these interactions

through sequence diagrams, elucidating the role of

blockchain. The fundamental idea is to ensure the

cybersecurity and data privacy of the patient’s med-

ical data while simultaneously guaranteeing autho-

rized entities access to records. An additional ben-

eﬁt of integrating the patient’s medical history into

the blockchain is to ensure that physicians can access

more comprehensive data, thereby contributing to a

detailed and reliable diagnosis. Subsequently, we de-

velop a proof of concept by implementing smart con-

tracts to manage medical records.

The paper is organized as follows. Section 2 pro-

vides the background of the work, including an ex-

ploration of the main concepts related to the theme

and a literature review. Section 3 delineates our pro-

posal, featuring the general architecture with enti-

ties and interactions involved in managing medical

records. Section 4 introduces a proof of concept, de-

tailing the technologies utilized in developing the ap-

plication, speciﬁcations of the smart contract, and an

overview of the conducted tests. In the ﬁnal section,

we conclude and indicate future work.

2 BACKGROUND

Blockchain is deﬁned as a decentralized and dis-

tributed digital ledger, serving to facilitate record

management and traceability (Javaid et al., 2021). Its

characteristic of decentralization is realized through

a peer-to-peer (P2P) network, where each node pos-

sesses a copy of the blockchain, ensuring heightened

security through the consensus algorithm. An ad-

vantageous feature of blockchain is the elimination

of intermediaries, as it allows direct interaction with

data without the need for intermediaries (Onik et al.,

2019).

The chain structure is essentially a linked list of

blocks, where each block includes the hash of the cur-

rent block, the hash of the previous block, and the

data ﬁeld. Tampering with a block would necessitate

changing the hash values of subsequent blocks and

gaining control of at least 50% of the network to effect

this alteration. Given the computational expense in-

volved, this process is deemed unfeasible, contribut-

ing to the characterization of blockchain as a mecha-

nism that stores information in an immutable way (Ali

et al., 2019).

Smart contracts are programs that execute on the

blockchain and are uniquely identiﬁed. These con-

tracts encompass key properties, including functions

and state variables. Additionally, these functions are

activated by speciﬁc input logic and execute when

transactions are requested. Programmers have the

ﬂexibility to write smart contracts in various lan-

guages, with the choice contingent on the program-

mer’s preferences and the platform selected for im-

plementing these contracts. For instance, on the

Ethereum platform, the Solidity language is com-

monly employed (Ali et al., 2019).

The application of blockchain in the healthcare

sector has gained signiﬁcant attention in academic cir-

cles, particularly driven by concerns about cyberse-

curity, reliability, and data privacy scandals. These

issues, coupled with the challenge of enhancing inter-

operability of medical data across different healthcare

entities, have spurred research in this area.

A decentralized approach (Madine et al., 2020)

is proposed to give patients control over their data,

involving entities such as insurance companies, pa-

tients, physicians, regulatory agencies, and hospitals.

The regulatory agency oversees patient and physi-

cian records, with authorization and deauthorization

schemes between physicians and patients. We extend

the focus of the approach (Madine et al., 2020) to in-

clude greater data interoperability and involve addi-

tional entities beyond the patient-physician relation-

ship.

Inspired by the work in (Carniel et al., 2021),

which describes a reliable approach to managing pop-

ulation vaccination data on a blockchain, our pro-

posal delves into entity details and relationships, em-

phasizing a broad consideration of patients’ medical

data. In the work of (Shen et al., 2019), a decen-

tralized patient-oriented network connects patients,

physicians, and healthcare providers to securely and

privately share data using blockchain technology. Our

proposal builds upon their work by incorporating

new entities, storing a wider variety of information,

and seeking to streamline the implementation process

with the use of smart contracts.

The work in (Shahnaz et al., 2019) discusses ap-

plying blockchain technology to Electronic Health

A Comprehensive Blockchain-Based Architecture for Healthcare Systems

251

Record (EHR) systems, focusing on an access control

schema for improved security. The system involves

only the administrator and user entities, with the ad-

ministrator deﬁning user roles (physician or patient)

and users making requests to validate themselves be-

fore any execution. In our work, we explore inter-

actions among various healthcare entities and detail

data exchange using blockchain to support a compre-

hensive solution.

In what follows, we present our proposal of the

blockchain-based architecture.

3 A BLOCKCHAIN-BASED

ARCHITECTURE FOR

HEALTHCARE SYSTEMS

The proposal aims to harness the capabilities

of blockchain technology, speciﬁcally through

smart contracts, to create an innovative medical

records management application. The utilization

of blockchain offers a robust solution to meet the

stringent requirements of cybersecurity, reliability,

and data privacy. Moreover, the integration of

smart contracts within the framework enhances the

interoperability of patient medical data, facilitating

seamless data sharing among various stakeholders in

the healthcare systems.

In Figure 1, we present a typical diagram show-

casing the roles of each class of entities and their in-

teractions within the blockchain in Brazil’s healthcare

system. The responsibilities of each class of entity are

described below.

• Patients. They are responsible for managing ac-

cess, authorizing necessary entities, and verifying

records.

• Physicians. They are responsible for updating pa-

tient records and checking patient histories.

• Regulators. They manage and monitor the

blockchain, by updating (registration, suspension,

reactivation) entities and monitoring their transac-

tions.

• Research Institutes. They access data from the

blockchain for research purposes.

• Pharmacies. They are responsible for checking

entity records and registering the drug acquisi-

tions to patients.

• Diagnostic Centers. They check the records of

patients to perform exams and store the results in

the blockchain.

• Insurance Companies. They are responsible for

checking the data and authorizing the release of

tests.

• Hospital Staff. They are responsible for autho-

rizing a medical appointment and assisting physi-

cians.

For a more detailed description of the interactions

among classes, we have selected ﬁve representative

classes: Patients, Physicians, Regulators, Pharmacies,

and Diagnostic Centers. The selection of Patients,

Physicians, and Regulators is justiﬁed by the sig-

niﬁcance of Physician-Patient interactions during ap-

pointments and the Regulator’s role in creating these

entities and assigning initial credentials. Addition-

ally, the choice of Pharmacies and Diagnostic Centers

aims to showcase common ﬂows and activities in the

healthcare system.

To describe the interactions among the selected

classes of entities in different scenarios, sequence di-

agrams are employed. Each sequence diagram out-

lines a ﬂow of interactions between entities. In the

sequence diagrams, we describe the interactions be-

tween single entities. For clarity, we employ “patient”

to refer to a single entity within the “Patients” class.

Similarly, this naming convention is applied to other

single entities and classes.

In Figure 2, the regulator entity, often represented

by the Government, assumes the responsibility of reg-

istering new entities to the system. During the reg-

istration process, an identiﬁer and a temporary pass-

word are assigned for the entity under analysis. Sub-

sequently, this information is stored in the blockchain.

Furthermore, the regulator is granted the authoriza-

tion to access patients’ medical records for manage-

ment and monitoring purposes.

In Figure 3, the interactions between a patient and

a physician during a medical consultation become ex-

plicit through the sequence diagram. Initially, both

the physician and the patient possess known iden-

tiﬁers from a previous step. Consequently, the pa-

tient can authorize access to the physician using the

physician’s identiﬁer. Once authorized by the patient,

the physician can review the patient’s records and,

based on clinical analysis, create a new record on the

blockchain. Consequently, the patient can access the

new record at any time. Records can be associated

with a prescription for necessary medication or the

requisition of additional medical exams.

In Figure 4, the sequence diagram between the pa-

tient and the diagnostic center is shown. Initially, the

patient must authorize the diagnostic center based on

the available identiﬁer. Subsequently, the diagnostic

center reviews the patient’s medical records to vali-

date the examination request speciﬁed by the patient.

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252

manages access

updates patient records

checks data for reasearch

checks data to provide

drugs

Research

Institutes

Pharmacies

Patients Doctors

Regulators

regulates use by organizations

checks records

Diagnostic

Centers

check records to perform exams

Insurance

Companies

access requested exams

deliberate abouts exams'

approval

Hospital Staff

approves the patient's

appointment

write the exam result

Figure 1: Blockchain-based architecture for a healthcare system.

Regulator Blockchain

Add actors ( doctor, patient, diagnostic center, pharmacy, regulator)

Check the information in the records

Figure 2: Sequence diagram of regulation.

Upon conﬁrming the request’s existence, the diagnos-

tic center authorizes the examination. Following the

completion of the process, the diagnostic center en-

ters the examination result into the patient’s record

information. Finally, the patient can review the ex-

amination results at any instant.

In Figure 5, the sequence diagram between the

patient and the pharmacy is outlined. Initially, the

patient must authorize the pharmacy entity to access

their records, considering that the patient knows the

pharmacy’s identiﬁer. Subsequently, the pharmacy re-

views the patient’s records to verify the availability of

Patient Doctor Blockchain

Authorizes access to the Doctor

Check patient records

Write a new patient record

Check a new record

Figure 3: Sequence diagram of medical consultation.

the requested medicine. If the prescribed medicine

for the patient is available, the pharmacy can effect

the acquisition and record it. This recording serves

to prevent the patient from acquiring any medication

twice if the medication is under control.

A Comprehensive Blockchain-Based Architecture for Healthcare Systems

253

Patient Diagnostic Center Blockchain

Authorizes access to the Diagnostic Center

Check exam in patient records

Authorize exam

Write the exam result

Check the exam result

Figure 4: Sequence diagram of exam.

Authorizes access to the Pharmacy

Check medications in patient records

Authorize purchase

Set drug status to purchased

Check the medicine purchased

Patient Pharmacy Blockchain

Figure 5: Sequence diagram of medicine acquisition.

4 A PROOF OF CONCEPT

In this section, we present a proof of concept for the

proposed blockchain-based architecture designed for

healthcare management. By illustrating interactions

among different entities in the healthcare system, the

proof of concept showcases how the proposed archi-

tecture enhances patient-centric care, facilitates data

sharing among entities, and ensures the integrity and

privacy of medical records.

Figure 6 demonstrates the integration between

some tools in the implementation of the proof of con-

cept. Trufﬂe is used to compile and deploy the smart

contract (written in the Solidity language). We con-

nect to the Ethereum blockchain (Goerli testnet) via

the Infura API. There is the bidirectional connection

of the DApp with the blockchain network using In-

fura. This connection incorporates a set of useful

tools on the front-end, such as the Browser (in this

case represented by Chrome), Metamask, React App,

and Web3. The code is available at (Marques, 2022).

To select the front-end tools, we opted for ReactJS

for creating the application’s user interface, Web3 for

interacting with Ethereum nodes, and Heroku for de-

ploying the platform on the web. The decision to use

the ReactJS library stems from its ability to facilitate

extensive component reuse in the code (Technostacks,

2023). The adoption of Web3 is driven by its status

as a JavaScript API that interfaces with blockchain

nodes. Lastly, the choice of Heroku is motivated by

its standing as a cloud application platform, ensuring

straightforward and rapid hosting of projects on the

web, along with simpliﬁed scalability in any applica-

tion.

For the blockchain technology, Ethereum is se-

lected as the platform for contract development. De-

spite being hosted on a public network, access con-

trol is ensured through patient login, authorization

mechanisms, and regulatory oversight, safeguarding

the integrity of blockchain information. Opting for

Ethereum on a public network enhances public ac-

ceptance compared to a private network. The Go-

erli test network was chosen for the developed project

due to its accessibility and cost-free availability of

faucets for testing, coupled with integration with In-

fura. However, it is important to note that this net-

work’s drawback is its usage by many applications,

which may result in slower transactions.

The use of Infura is imperative for DApps (De-

centralized Applications). In essence, Infura is a

blockchain infrastructure-as-a-service (IaaS) provider

that offers developers simpliﬁed access to blockchain

networks. It acts as a middleware service, abstracting

the complexities associated with running and main-

taining a node on a blockchain network. Infura pro-

vides a convenient and reliable way for developers to

interact with blockchain networks without the need to

manage their nodes (Macedo, 2020).

Trufﬂe is selected due to its status as an Ethereum

blockchain development environment for DApps. It

provides an all-encompassing solution with built-in

support for building, testing, deploying, and binding

smart contracts. Additionally, it offers an interactive

console for communication with these contracts and

network management for both public and private net-

works.In terms of complementary tools, Metamask

(as a digital wallet) and Git (as code versioning sys-

tem) were utilized.

In a way to organize the smart contract, we di-

vided it into the following classes: structures, map-

pings, counters, constructors, and functions. Below,

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Smart Contract

compiles and deploys

connects ethereum and

runs hosted nodes

Browser

Metamask

React App

Web3

connects DApp with ethereum

blockchain

Goerli

network

Figure 6: Technological tools used in the proof of concept.

each of these classes and their applications are pre-

sented.

• The structures contain the declaration of entities

that are members of the classes of entities (Pa-

tients, Physicians, Regulators, Pharmacies, Diag-

nostic Centers), as well as entities that support the

interactions. These latter entities are members of

the classes Diagnoses, Exams, and Medicines.

• Regarding the mappings, there exists a key-value

relationship to form vectors and matrices for the

aforementioned structures, as well as vectors re-

lated to access authorizations for the Medical,

Pharmacy, and Diagnostic Center entities.

• The counters are utilized to deﬁne numbers of

elements of entity classes, making this informa-

tion public so that the limits to the mappings are

known by the functions.

• The use of constructors deﬁnes the initial entities

of the platform.

• The use of functions is what triggers transactions

and writes some information to the blockchain.

These functions play an essential role in the over-

all functionality of the smart contract.

To exemplify how the contract is speciﬁed in code,

we can consider a speciﬁc scenario of the interaction

between a patient and a physician during the con-

sultation (as presented in Figure 3). As structures,

we have Diagnosis, Patient, and Physician. Firstly,

the Diagnosis structure includes the ‘diagnosis code’

ﬁeld, which will be inserted according to the value

presented in the ICD table (International Classiﬁca-

tion of Diseases) (Harrison et al., 2021); the ‘exam

code’ ﬁeld, based on the TUSS table (Uniﬁed Ter-

minology of Supplementary Health) for the classi-

ﬁcation of procedures in Brazil (ANS, 2019); and

the prescriptions for medicines using the ‘medicine

code’, based on the medication number present in the

open data made available by the Brazilian government

(ANVISA, 2020). The Diagnosis structure also in-

cludes the time of consultation, the physician’s ID,

the physician’s observation, and the prescriptions for

exams.

In the Patient structure, the patient’s ID and pass-

word ﬁelds are used in the patient’s login; the number-

of-appointments ﬁeld is used to control the number of

consultations that the patient had; the token ﬁeld is

used to perform user veriﬁcation more securely when

entering the platform; and the name ﬁeld is used to

describe the patient. As for the Physician structure, it

follows the same pattern as the Patient structure but

adds the ﬁelds of CRM (physician’s certiﬁcation in

the regional council of medicine) and the physician’s

specialty.

Considering the scenario of consultation in Figure

3, the mappings of the smart contract contain infor-

mation in the form of a key-value, for instance, a list

of physicians, a list of patients, a list of authorized

physicians by patients, and list of diagnoses by pa-

tients. Regarding the counters in the smart contract,

we deﬁned the following: number of patients, number

of physicians, number of regulators, quantity of phar-

macies, and quantity of diagnosis centers. We add

only one constructor in this case, to create a regulator,

which in turn allows the creation of other entities for

test purposes. Two functions are speciﬁed to manage

the interactions between patients and physicians: the

authorization function of any entity (physician, phar-

macy, or diagnosis center) and the code about patient

consultation (which allows the creation of new medi-

cal records for the patient).

A Comprehensive Blockchain-Based Architecture for Healthcare Systems

255

In a way to test the developed application, we an-

alyze the ﬂow of interactions through a real-life sce-

nario. In this scenario, a patient is unwell and seeks

a physician for appropriate treatment. The idea is

to outline a comprehensive sequence of interactions

as the patient engages with the medical, pharmacy,

and diagnostic center entities while utilizing the de-

veloped platform to manage his records.

Here is a breakdown of the key steps in the sce-

nario. The patient initiates the platform login and de-

cides whether to authorize the physician (using the

screen in Figure 7). If the authorization is granted,

the physician accesses the patient’s records and adds

a new entry (using the screen in Figure 8). If not, the

interaction is terminated.

Figure 7: Patient authorization screen.

Figure 8: Screen for the physician to add appointment in-

formation.

The patient checks whether the physician has pre-

scribed any medication. If so, the patient proceeds to

request the acquisition of the prescribed drug from a

pharmacy. Authorization must be granted to the phar-

macy entity for this transaction to proceed; otherwise,

the interaction ends. If authorization is granted, a

pharmacy staff member reviews the records and ap-

proves the acquisition in the system, concluding the

interaction between these entities.

The patient checks whether the physician has pre-

scribed any diagnostic tests. If there are test requests,

the patient contacts the diagnostic center to schedule

the examination. To initiate this process, the patient

must authorize the diagnostic center to access their

records. Once authorized, the diagnostic center re-

views the requested test and conducts the examina-

tion. Finally, the diagnostic center records the test

results in the patient’s medical records.

Upon completing these steps, the interactions

within this scenario terminate. It is worth noting that

this sequence of procedures can be repeated for subse-

quent appointments. We tested all these sequence di-

agrams with the implementation of our proof of con-

cept. All the tests were executed with success.

5 CONCLUSIONS

The proposed architecture consists of entities and

their interactions involved in the healthcare system

using the blockchain technology. Each entity, in-

cluding patients, healthcare providers, regulators, and

others, plays an essential role in contributing to a

comprehensive and collaborative healthcare system.

The architecture serves as a blueprint for understand-

ing the ﬂow of information, transactions, and permis-

sions within the application. It highlights the seam-

less interaction between entities and the blockchain.

Blockchain, with proper controls, ensures that entity

data is not only secure but also accessible and share-

able.

The decentralized and immutable nature of the

blockchain ensures a tamper-resistant environment,

instilling trust in the integrity of patient data. The

cornerstone of our application lies in the implemen-

tation of smart contracts. These self-executing con-

tracts operate on the blockchain, fostering a secure

and automated environment. Notably, the smart con-

tract framework enhances the interoperability of pa-

tient medical data, enabling efﬁcient and secure data

sharing among diverse entities in healthcare systems.

Through the proof of concept implementation, we

aimed to validate the viability and effectiveness of the

proposed solution. The proof of concept provided

insights into the seamless coordination between pa-

tients, physicians, regulatory entities, pharmacies, di-

agnostic centers, and other stakeholders within the

blockchain-based framework. It is important to note

that the patient is the rightful owner of their data and

has the authority to grant access to speciﬁc entities for

their transactions. This feature aligns with the princi-

ples of data protection outlined in GDPR and LGPD.

Our proposal contributes to enhancing the reliabil-

ity of the physician’s diagnosis process by providing

access to the complete patient history, including med-

ications and exam results. Furthermore, it ensures a

more dependable medication control system, allow-

ing pharmacies to prevent irregular acquisitions. Reg-

ulatory entities beneﬁt from broad access to the med-

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256

ical data of the population, empowering the formula-

tion of comprehensive public health policies.

As part of our future work, we aim to integrate

additional entities outlined in our proposal, for in-

stance, the health research institutes, pharmaceutical

and biotechnology companies, and health insurance

providers. The sequence diagrams could be enhanced

with supplementary interactions to better reﬂect the

complexity of the problem at hand. Conducting tests

with real users is also crucial. Another issue that de-

serves some care is the application’s usability, mainly

for the patients, since they may have health restric-

tions to interact with the system.

On the implementation front, considering the

costs associated with Ethereum transactions, we need

to explore the possibility of replacing it with non-

monetary blockchain platforms. The scalability of

blockchain solutions refers to the system’s ability to

handle a growing amount of work, transactions, or

users effectively without compromising performance.

Scalability is a critical consideration for blockchain

networks. We view it as a relevant concern that mer-

its further investigation.

This work signiﬁes an endeavor to harness the

power of blockchain and smart contracts for the en-

hancement of healthcare systems, tackling challenges

related to cybersecurity, reliability, and data privacy.

Moving ahead, the proposed architecture has the po-

tential to elevate patient care, streamline healthcare

processes, and promote a more interconnected and

collaborative healthcare landscape.

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