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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Overview⋆</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Alessio Famiani</string-name>
          <email>alessio.famiani@unito.it</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Ruggero G. Pensa</string-name>
          <email>ruggero.pensa@unito.it</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Università di Torino</institution>
          ,
          <addr-line>Dipartimento di Informatica, Via Pessinetto, 12, 10149 Torino TO)</addr-line>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2025</year>
      </pub-date>
      <fpage>9</fpage>
      <lpage>11</lpage>
      <abstract>
        <p>Data has been playing a crucial rule in healthcare. Its digitisation and exchange have improved the delivery of healthcare to patients and fostered scientific research. However handling the workflow and governance of such data is not a trivial matter, due to legal and technical barriers. The aim of this paper is to explore existing health data sharing schemes to identify trends and desiderata for a hypothetical system that meets the legal requirements for handling data for scientific research. This discussion highlights the importance of interoperability to address the fragmented nature of data and emphasises the need for data owners' autonomy and empowerment, alongside technical trends that can help achieve these goals.</p>
      </abstract>
      <kwd-group>
        <kwd>health data</kwd>
        <kwd>privacy</kwd>
        <kwd>biomedical research</kwd>
        <kwd>data spaces</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        Data has increasingly become a valuable resource in many sectors, if not all, and has played a crucial
role in the healthcare setting. Over the years, the digitisation of health data and its exchange have
improved the delivery of healthcare to patients, facilitated the collaboration of various stakeholders
within the sector, and also fostered scientific research [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. Nowadays, patients have the ability to view
and download their health records, including laboratory results, exams, visits, and drug prescriptions,
using online platforms. Additionally, they can monitor their health status by using wearables or other
IoT devices that collect and process various metrics. Doctors and specialists can issue certifications,
prescriptions, and documentation regarding patients using these same platforms. In addition, health
institutions can also collect and share these records for collaborating with scientists. However, handling
the workflow and governance of this type of data is not a trivial matter.
      </p>
      <p>CEUR
Workshop</p>
      <p>ISSN1613-0073</p>
    </sec>
    <sec id="sec-2">
      <title>2. Technical and legal burdens</title>
      <p>There are many burdens, of diferent nature, that users, developers, and researchers might face during
the use or development of systems dealing with such data.</p>
      <p>
        Technical burdens From a technical point of view, the main challenges come from the lack of
interoperability among systems belonging to diferent medical sites and organisations, as well as
applications related to healthcare and/or wellbeing. Data is scattered across multiple locations
and services which usually do not communicate with each other, which may use diferent schemas,
standards, or data formats. This makes it dificult for patients to receive healthcare from diferent medical
institutions and get a clear overall picture of their own health [
        <xref ref-type="bibr" rid="ref1 ref2">1, 2</xref>
        ]. An issue that is worth mentioning
is related to the obvious concerns about data security and privacy for both in-transit and at-rest
data [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. Breaches involving such sensitive data can have harmful consequences on the people data is
about and their lives. This ranges from identity theft, discrimination, reputation or financial damages,
to the inability of accessing data on them and so on. This also negatively influences the level of
trust of the system and the related institution, making people reluctant to share their data [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. However,
when adopting potential countermeasures, the ability to access one’s data in emergency situations
should be taken into account, a feature also known as break the glass [
        <xref ref-type="bibr" rid="ref4 ref5">4, 5</xref>
        ], and, more generally, some
delegation mechanisms [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]. For what concerns scientific research, the aforementioned fragmentation
can cause dificulties in retrieving high quality data , since data can encounter diferent barriers
during its collection. For instance, it can be challenging to obtain and combine all the data belonging
to the same individual [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. Diferent medical sites or data sources may have varying indexing and
techniques for identifying users within their systems, which can difer from each other. Caution should
also be exercised in the assessment, and eventually in the mitigation, of possible biases and
errors that can be found within the collected data [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. A non-trivial aspect is also represented by the
ability to find and query data in a privacy-respectful and safe manner, also under the assumption
of not having access to it yet. Core point is how to perform research on data while respecting
people privacy and data security (i.e., it should not be possible to infer that someone was included
or not in the research or perform research on encrypted data).
      </p>
      <p>
        Legal burdens When it comes to legal barriers, given our involvement in the PADS4Health project,
we’ll focus on the European framework. The European legal context on matters of privacy, share
and reuse of health data for secondary purposes is largely influenced by the General Data Protection
Regulation (GDPR) [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. GDPR is the most relevant European law on privacy, which defines the rights
individuals, known as data subjects, have on their data. It imposes obligations for controllers and
processors, and fines for unlawful behaviours. Plus, it also helped raise awareness on privacy issues.
The GDPR is a pervasive regulation since it applies to all personal data, protects EU citizens globally,
and has brought legal harmonisation across Member States. Thus, its scope of application is broader
and more consistent compared to other legal contexts around the world. For instance, in the USA, the
landscape is fragmented, with privacy laws regulating specific sectors, resulting in a narrower range of
protection. A US privacy law regulating health data sharing privacy and security is represented by the
Health Insurance Portability and Accountability Act (HIPAA) [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. It is a federal law which regulates the
privacy of the so called Protected Health Information (PHI) treated by specified entities. It protects PHI
within US borders and not worldwide like GDPR does.
      </p>
      <p>
        Additionally, over the years, laws and regulations have been enacted to discipline privacy and data
exchange in the public sector or for public interests, including scientific research. Some are built upon
the GDPR, denoting again the relevance of this regulation. The Open Data Directive [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ] and Data
Governance Act (DGA) [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ] encourage the re-use of data in the public sector and its secure exchange.
Interestingly, DGA defines and regulates the figures of data intermediaries and the concept of data
altruism, which refers to data donated by individuals for general interest purposes. A more recent
regulation, the European Health Data Space (EHDS) [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ], aims at establishing a common space for health
data for both primary use, concerning the delivery of healthcare within EU borders, and secondary
use, referring to the use of data for public interest purposes (e.g. scientific research). It also institutes
various intermediary figures for data exchange and access, other than interoperability aspects. Art. 110
of the Italian Privacy Code [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ] norms the use of health data for medical, biomedical and epidemiological
research, also in circumstances where data subjects cannot give consent. Referring to the technical
issues previously discussed, having data scattered across diferent locations makes it harder for data
subjects to exercise control over their data and their rights [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ]. In addition, the redundancy
coming from the collection of the same details of data subjects by multiple parties colludes with the
principles of data minimisation and once-and-only [
        <xref ref-type="bibr" rid="ref15 ref8">8, 15</xref>
        ]. The collection, exchange and re-use of
data also has to be compliant with existing regulations, other than respecting and protecting people
rights and freedom. Eventually, it should also be taken into account the need of keeping track of
diferent legal bases aside consent [
        <xref ref-type="bibr" rid="ref13 ref8">8, 13</xref>
        ]. Especially in the secondary use case, research needs to
be privacy-preserving and respectful. All this by taking into account the eventual need to protect
intellectual property of researches, institutions, and related [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ].
      </p>
    </sec>
    <sec id="sec-3">
      <title>3. Data sharing schemes in literature and real life examples</title>
      <p>
        Given the fragmented nature and the vulnerability centralised solutions face due to potential breaches
exposing large amounts of data, developers came up with various schemes over the years to efectively
and safely exchange health data for research. In the following paragraphs, we will explore various
health data sharing systems in literature, examining their architectures (their overall structure), data
lfow patterns (how data is shared and handled across/within systems), and security and privacy
considerations (how sensitive information is protected). At the end of this section, we will also tackle
a few interoperability resources and briefly illustrate two real life examples of such systems in action.
Architectures One example is SHRINE [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ], an open source project whose goal is to aggregate patient
observations scattered across hospitals in a standard manner in order to re-use these information for
research activities. Its architecture consists in a P2P network with no central authority, where each
medical site handles it own storage, security and verifies its own researchers. Local warehouses are
run by i2b21 instances. [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ] instead supports collaborative research by enabling federated analysis on
individual-level data stored on various databases, each one curated and maintained by a participant site.
The architecture consists of a central computational node performing the analysis, capable of issuing
commands to several nodes where data is stored and queried locally in a parallel fashion. In [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ] the
authors developed a federated system which enables clinical sites to safely outsource their data for
distributed genomic and clinical analysis. Each institution can choose its preferred storage solution: its
own, a governmental one or a cloud provider’s. This way sites can ofload maintenance and availability
burdens. These units form a secure, federated and interoperable network. PHT [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ] is a system that
implements FAIR principles and machine readability is at the core: interpretable workflows, services,
data and metadata. PHT is organised in: stations, the participant sites, where data is stored; trains,
analytical workflows performed within stations; tracks, intermediaries maintained by trusted parties
that enforce rules and connect trains and stations. The authors of [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ] rely on Federated Learning (FL)
in a cross-device setting, generalisable to larger federation units, for performing analysis on distributed
individual-level health data perturbed by Diferential Privacy (DP) techniques. [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ] proposed a system
backed by permissioned blockchain technology, specifically designed for handling research of Covid-19
electronical medical records. Blockchain access is restricted: nodes, such as hospitals and research
institutions, need to register and authenticate before transmissions and query. [
        <xref ref-type="bibr" rid="ref22">22</xref>
        ] is a toolkit2 made
for aiding researchers to perform various privacy-preserving federated analysis on genomic data. It
consists of a web server and command line interface (CLI), and enables users to create, set up and
run collaborative analysis. A coordinator handles the studies. In [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ], the system is made of study
participants (SPs), individuals, institutions or data custodians that own the data, and computing parties
      </p>
      <p>
        (a) PHT
(b) Cho et. al
(c) DataSHIELD
(CPs), entities with appropriate computing powers which jointly carry out the analysis. A diferent
scheme instead is used in [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ], where data providers and queriers are interconnected. Each site perform
local computation and encrypts intermediate results. These results are later aggregated and redistributed
for further computation iteratively until convergence is reached.
      </p>
      <p>
        Data flows In [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ] only authorised analysts perform searches for patient populations matching some
criteria, specified using terms of an ontology defining a set of standardised medical concepts. Each
peer needs to map its own terms to this common ontology. Queries are broadcasted to participant
institutions and computed locally. Anonymised and aggregated results are then presented to the
investigator progressively as they become available. [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ] uses another type of approach (see Figure 1b):
at the beginning of the study relevant features are chosen and data harmonised but still partitioned.
A researcher can issue commands that specify which kind of operations have to be performed locally.
Local databases are powered by Opal3. Non-identifiable results are then sent back to the investigator
and aggregated in such a way that returned outputs resemble non-disclosive study level statistics.
This might be an iterative process. In [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ] each site transforms data from its private system to match
a predefined schema and a set of medical ontologies concepts for interoperability purposes. Local
warehouse are run by ib2b instances. Investigators can then access and query encrypted data as if
it’s coming from a single source, without the need of decrypting it first. In PHT [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ] stations host
and manage their own data, run their own system, define interfaces for executing queries and provide
computational resources for performing analysis within a secure environment (see Figure 1a). Technical
choices are encoded into metadata for interoperability and discoverability purposes. Researchers build
and maintain trains, objects containing all the information needed to run distributed analysis algorithms.
Researchers are entirely decoupled from the computation phase. Tracks orchestrate workflows
end-toend and are responsible for train forwarding, results aggregation, transaction management and rules
enforcement. Every object above has a unique ID and is tracked in a registry. Data in [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ] is distributed
across repositories and never sent outside of them. Sub-models are learned locally and then aggregated.
Updates are performed locally. In [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ] anonymised records of patients are stored on the chain upon
previous consent in order to make them searchable. Results of research can also be stored on the
platform for keeping track of progress in the field and protect intellectual property. Researchers issue
query and/or upload requests. In [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ] each SP securely shares their data with the CPs, which jointly
execute an interactive protocol to accomplish the required analysis task (see Figure 1c). Finally, CPs
combine their results together to obtain the final statistics and publish them. While in [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ] a queries
sends a query in clear, data providers perform the requested query locally on clear data and then send
to each other encrypted results. Then, these results are aggregated and the process is repeated until
convergence. Final results are sent to the querier.
      </p>
      <p>
        Security and privacy details In [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ] only authorised investigators can perform requests for queries,
which are then verified at destination institutions. SHRINE uses digital certificates and signatures to
secure communication and for identifying participants. Results are anonymised by default. In [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]
researchers can issues only safe and approved operations in R and only non-identifiable outputs are
returned. [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ] uses Homomorphic Encryption (HE) and obfuscation techniques to provide privacy
and security guarantees. Data remains encrypted end-to-end and authorised researchers are able to
decrypt just the results. Every participant is involved in the encryption key generation process, so
not even a compromised site can decrypt data alone. Depending on diferent privileges levels, it may
also be impossible for an investigator to trace back responses to the original clinical site. As in other
works, in [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ] data never leaves its origin and is processed in a secure environment provided by its
location. Data sovereignty is emphasized in the system and results are communicated via open protocols
mandating authentication and authorisation procedures. Consortium blockchain technology in [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ]
and access control performed by the nodes of the alliance ensure only authorised users can access
and upload data on the chain. Data is uploaded only upon consent of the patient, who directly has
to authorise the operation. Integrity and identities check is ensured by the nature of the blockchain.
Records are anonymised, and patients’ identities are replaced with pseudonyms in the chain. [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ] uses
MPC protocol and during exchange inputs stay private. No CP can learn anything about the raw data
aside from the final published results. Cryptographic methods secure data during its exchange and
processing. [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ] uses Multiparty HE (MHE), so all results, both intermediate and final, are encrypted
and privacy is ensured end-to-end. Obfuscation techniques are used on final result to preserve accuracy.
Real life systems Around the world, many countries have adopted systems for managing health data
for better assisting patients within their national healthcare system, and also for fostering scientific
research from data previously shared by patients.
      </p>
      <p>
        Some initiatives rely on entities called data enclaves or data custodians [
        <xref ref-type="bibr" rid="ref25">25</xref>
        ], trusted parties where
individual-level data from multiple sources are safely stored and where privacy-friendly research is
performed. In Scotland, for example, within the Scotland National Safe Haven project [26], secure
physical locations under some administrative arrangements safely store data coming from the National
Health Service (NHS) for research purposes. The environments ofer various pre-installed software and
high-powered computing resources for performing analysis on pseudonymised individual-level data
or aggregates. There is the possibility of grating remote access to investigators but no possibility of
downloading data. Release of outputs are subject to human screening and statistical disclosure methods.
Data retention policies have also been put in place.
      </p>
      <p>A more advanced and recent system is adopted in Estonia. The e-Health Record [27] is a
blockchainbacked [28] healthcare system which retrieves data as necessary from various providers that potentially
use diferent systems and presents it in a standard format. This thanks to a secure distributed information
exchange platform: X-road [29]. The system follows the principle of once-only: information is never
asked twice. The system is backed by the Keyless Signature Infrastructure (KSI) blockchain, a scalable
alternative to Public Key Infrastructure (PKI) for verifying integrity and authenticity of data and processes
in zero-trust applications. Anonymised data is also made available for research purposes, plus the data
collected within the system helped build a few databases for such objectives.</p>
      <p>
        Resources for interoperability As seen previously, many systems interface with some biomedical
electronic resources available online, while others adhere to some standards of the sector. Example of this
are: the Observational Health Data Sciences and Informatics (OHDSI, pronounced Odyssey) [30], a project
whose goal is bringing out the value of health data through large scale analytics. The main contribution
is represented by the development of a common data model and the help in its adoption. Data stored in
diferent observational databases can be converted into this standard for enabling the reliable large-scale
analysis. As cited before, the Estonian X-road [29] is another case. This data exchange platform allows
secure and standardised communication between diferent information systems, both private and public.
It is capable of transmitting large quantities of data and performs searches simultaneously across several
information systems. In [
        <xref ref-type="bibr" rid="ref17">17, 31</xref>
        ], an ontology, The Shrine Core Ontology, is used for data harmonisation.
It is a collection of diferent concepts available in other resources concerning demographics, diagnoses,
medications and laboratory tests. For instance, ICD-9-CM [32] is used for categorising diseases, which
is the International Classification of Diseases standardised by the World Health Organisation (WHO).
Another attempt worth mentioning is the National Center for Biomedical Ontology (NCBO) repository
[33], which gives open access to various biomedical ontologies and also includes mappings between
terms of diferent resources.
      </p>
    </sec>
    <sec id="sec-4">
      <title>4. Discussion</title>
      <p>
        As the authors of [
        <xref ref-type="bibr" rid="ref25">25</xref>
        ] argue, the approaches usually fall into three main categories: Distributed
data analysis: where parties locally execute computations on their data, exchange partial results,
and aggregate them across locations; Cryptographic Secure Multi-party Computation Systems:
exchange of data is encrypted and only aggregated statistics can be decrypted; Data enclaves: data
from multiple sources is merged in a single curated repository hosted by a trusted party. In addition,
Blockchain technology could fall into a category of its own.
      </p>
      <p>
        Despite the diversities of the illustrated works, several trends emerge. Firstly, the majority of the
systems acknowledge the distributed nature of the healthcare domain by employing federated,
distributed and/or decentralised architectures for enabling health data sharing for scientific research
while respecting participants’ privacy. Some works addressed this aspect by highlighting the need
for interoperability via common standards and mapping tools. For example, in [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ] participants
institutions map their data schemes to a unified ontology of medical concepts, providing standardised
ways for describing diseases, symptoms and drugs. This ensure data is harmonised across heterogeneous
sites. However, it’s important to note that converting data formats and mapping schemes can cause
bottlenecks in the data flow. Plus, [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ] and [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ] are built on widely used frameworks for clinical
research. The approach used in [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ] implemented FAIR principles [34] in order to make every aspect
(i.e., data and analyses) of the workflows machine-readable, thus interoperable. It also clearly emerges
the respect for participants autonomy and data sovereignty. For a medical site, it is usually
desirable to have flexibility regarding the EHR system to use, data administration and governance,
and also which computing environment or hosting solution to use. Data usually never leaves its
original location, or at least not in a plain format, and it is queried in a federated manner, giving the
perception that diferent data reside in the same place. In certain architectures, such as [ 35] data owners
empowerment is also emphasized. For what concerns studies performed in a privacy-friendly manner,
widely used technologies are Federated Learning (FL), Diferential Privacy (DP) for obfuscating results
and perturbing individual level data. However, a rising trend is given by cryptographic techniques
like Secure Multiparty Computation (MPC) which enables participants to jointly perform computations
without disclosing raw inputs, and Homomorphic Encryption (HE) that make able to perform operations
on data without the need of decrypting it first. They are costly from a computationally perspective but
avoid many legal barriers since encrypted data is anonymised, thus not regulated under the GDPR.
Identified requirements Besides what concerns the primary use of health data, starting from the
analysis of the related literature, we have identified the following requirements for a system dealing
with health data for research. A patient-centric approach can give power and ownership back to
data subjects, since they can exercise their data rights intuitively and in a more efective manner. For
example, they can revoke consents for treatments of their data where applicable, request and perform
updates on their information or pause data processing selectively. Seeing and managing the flow of
their own data can enhance individuals’ awareness on the topic of privacy and their related rights. Data
collection should be in accordance with the principles of data minimisation and once-only (gathered
data can be shared with others later). This can help decrease management costs and improve privacy
and trust. Enforcing data retention policies is also another crucial point. As other laws already
require, logging and tracing every activity on data and access to it could help in the auditing processes
and in being more transparent in general. This could also help in demonstrating the compliance with
the GDPR and other laws, and for holding institutions and people accountable. It can also be helpful
to keep track of legal bases (the most “popular” one being data subject’s consent) and purposes of
data processing. This can be beneficial also to data processors and data holders for demonstrating
compliance. For what directly impacts scientific research, researchers could perform searches on
data without having yet access to it, in order to retrieve data having certain properties without
leaking information about individuals owning the data. Alternatively, they could have the ability to
open “data campaigns” which are containers populated by crowdsourcing health information
donated by data subjects (informed about the platform following criteria specified by the researchers).
To achieve this, data subjects should have the ability to donate their data for research or for
other public interest objectives upon previous anonymisation (when feasible) or pseudonymisation,
automatically performed to protect their privacy and identity. This way, researchers can have access to
large sets of complete and up-to-date health-related data upon which they can study and perform
learning while respecting people’s privacy and privacy principles (e.g., not retaining data more
than needed). Generally, approaches like this can substantially improve the workflow of scientific
research, resulting in faster scientific progress and better results. A broader list of requirements, along
with some possible technical solutions, can be found in Table 1.
      </p>
    </sec>
    <sec id="sec-5">
      <title>5. Conclusions</title>
      <p>
        In the last few years, huge advancements have been made in the exchange of health data and its
re-use for biomedical studies. The selected works covered a diverse spectrum of privacy-preserving
architectures, data flows, security and privacy-related practises, thereby highlighting certain trends.
The distributed nature of this domain underscores the importance of interoperability via common
standards, shared resources or applications, and open protocols. The respect for participants’ autonomy
in managing their own systems and data, coupled with the need for data owners’ empowerment,
Safe Search on data
Privacy-Preserving Analysis
Bias and errors detection and mitigation [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]
Improving workflow of scientific research [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]
Protect intellectual property [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]
Impossibility of downloading data [26, 37, 38]
Respect institutions autonomy [
        <xref ref-type="bibr" rid="ref17 ref18 ref19">19, 17, 18</xref>
        ]
Keep data subjects aware and informed [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]
Processing Ledgers [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]
Data portability and interoperability [
        <xref ref-type="bibr" rid="ref1 ref2">1, 2</xref>
        ]
Delegation Mechanisms [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]
Records Linkage and deduplication support [39]
Management of legal bases [
        <xref ref-type="bibr" rid="ref13 ref8">13, 8</xref>
        ]
Security of at-rest and in-transit data
Non-repudiation
Integrity
General robustness from attacks
Availability, Disaster Recovery and Fault Tolerance
Auditing, activities tracing and logging
Anonymisation and pseudonymisation procedures
Data minimisation and once-only principles [
        <xref ref-type="bibr" rid="ref15 ref8">8, 15</xref>
        ]
Access control, authorisation and authentication
Symmetric Searchable Encryption, Zero-Knowledge
Proof
Federated Learning, Homomorphic Encryption,
Synthetic Data Generation, Diferential Privacy,
Statistical Disclosure Control
Data quality dashboards, Pattern Recognition/Data
Mining, Anomaly Detection
Machine Learning Techniques for pre-processing
Watermarking, Secure Multiparty Computation,
Digital Signature, Encryption, Virtualisation and
Sandboxing
Virtualisation, Sandboxing
Federated Learning, Secure Multiparty Computation,
Blockchain
Dashboards, ”Privacy Labels”, Smart Contracts
Blockchain
Ontologies
Smart Contracts, Proxy re-encryption, Attribute Based
Encryption, Broadcast Encryption
Hashing, Probabilistic Record Linkage
Ontologies, Vocabularies, Technology for the Semantic
Web, Smart Contracts
Symmetric key encryption, Public-key encryption,
Identity-Based Encryption, Attribute Based
Encryption, Proxy re-encryption
Digital Signature, Digital Certificates, Blockchain
Hashing, Encryption, Digital signature
Proof of Work (hashing), Encryption
Cloud, Blockchain, Proof of Work (hashing), Backup
solutions
Blockchain
Diferential Privacy, Symmetric Encryption
Single Sign-On, Data Masking and Anonymisation
Smart contracts (blockchain), Proxy re-encryption,
Attribute Based Encryption, Attribute Based Access
Control, Access Control Lists, Single Sign-On, Smart
      </p>
      <p>Contracts
Data Governance, awareness and compliance</p>
      <p>Security &amp; Privacy
are particularly emphasised. Furthermore, there are also emerging technological trends in
privacyfriendly analysis, such as the usage of cryptographic techniques, federated learning, and diferential
privacy. In conjunction with legal frameworks, these developments have facilitated the identification
of specific requirements for a solution that efectively addresses both technical and legal obstacles
initially elucidated. Finally, this collaborative efort has resulted in the compilation of a draft of technical
solutions tailored to the identified requirements.</p>
    </sec>
    <sec id="sec-6">
      <title>Acknowledgments</title>
      <p>The work presented in this paper is funded by the European Union – Next Generation EU, Mission
4 Component 2 Investment 1.1 CUP D53D23022370001 (GA n. P2022MSMAW), PRIN 2022 PNRR
“PADS4Health”.</p>
    </sec>
    <sec id="sec-7">
      <title>Declaration on Generative AI</title>
      <p>During the preparation of this work, the author(s) used Apple Intelligence in order to: Grammar and
spelling check.
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