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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Flemish Health Data Space Implementation: Technical Overview and Challenges</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Xueying Deng</string-name>
          <email>xueying.deng@imec.be</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Matthias De Geyter</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Bart Matthys</string-name>
          <email>bart.matthys@imec.be</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Casper Van Gheluwe</string-name>
          <email>casper.vangheluwe@imec.be</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>David Vermeir</string-name>
          <email>david.vermeir@imec.be</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Matthias Stevens</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>imec Gent</institution>
          ,
          <addr-line>De Krook, Miriam Makebaplein 1, 9000 Ghent, Belgium. https://</addr-line>
        </aff>
      </contrib-group>
      <abstract>
        <p>This paper presents the implementation of a Health Data Space in Flanders, Belgium. The project integrated the fundamental components of a data space while also catering to specific customer requirements. The project utilizes the Eclipse Dataspace Components (EDC) implementation of the Dataspace Protocol, Keycloak as an Identity Provider, and DataHub as the intermediary Metadata Broker to allow data discovery within a data space or across data spaces. In addition, a Clearing House was developed based on customer requirements. The paper presents a state-of-the-art implementation of a data space and provides valuable information on the application of data space concepts within the health sector. It also presents a study of current Electronic Health Records (EHR) data models for semantic interoperability and machine-to-machine data discovery, addressing the data discovery challenge.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Data Space</kwd>
        <kwd>Data Discovery</kwd>
        <kwd>Linked Data</kwd>
        <kwd>Eclipse Dataspace Components (EDC)</kwd>
        <kwd>Clearing House</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        In February 2020, the European Commission1 published ‘A European Strategy for Data’ [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] (referred
to in this article as ‘EU data strategy’), as part of a wider drive concerning digital transformation
and policy [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. The EU data strategy creates diferent rules and institutions that seek to improve and
facilitate data access and enhance data utilization [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. In response to the call for an EU data strategy, the
initiative to build Common European Data Spaces has emerged [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. The first objective mentioned in the
European data strategy is to improve healthcare and promote interoperability within the health sector
in Europe [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. In May 2022, the European Commission presented its proposal to set up a European
Health Data Space (EHDS) aiming to unleash the full potential of health data [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]. In alignment with
European initiatives, the Flemish Health Data Space (referred to in this article as ‘Health Data Space’)
project was started.
      </p>
      <p>
        Within the Health Data Space project [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], the Business Intelligence (BI) and Data ofice of the Flemish
Department of Care and imec collaborated to shape the future of data-driven health policy. Our focus is
on investigating the technical, ethical, data processing, and legal prerequisites necessary to establish a
data space dedicated to health policy.
      </p>
      <p>
        This paper aims to demonstrate how data space components can be implemented within the health
sector. The technical implementation of the components within the data space aligns with those
identified by IDS Reference Architecture Model (RAM) 4.0 [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] published by the International Data
Spaces Association (IDSA). RAM 4.0 outlines the framework for how a data space should be structured
from a component perspective, organized into five layers (Business, Functional, Information, Process,
and System) and three horizontal aspects (Security, Certification, and Governance).
      </p>
      <p>The technical solutions implemented in the Health Data Space are highlighted in orange in Figure 1
below. Each component will be elaborated upon in the subsequent sections.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Dataspace Connector</title>
      <p>
        Numerous data space connectors [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ] are currently being developed, and an overview can be found in
the Data Spaces Radar [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. When selecting a connector, the primary considerations from the Health
Data Space perspective include the following.
      </p>
      <p>• Interoperability: The connector’s ability to work seamlessly with other connectors.
• Extensibility: The potential for customization and enhancement of the connector.
• Community Support and Active Development: The availability of resources and ongoing
improvements.</p>
      <p>
        The Dataspace Protocol (DSP) is the specification that standardizes communication among connectors
for data transfer and negotiations [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. The Eclipse Dataspace Components (EDC) provide a framework
for sovereign [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ], inter-organizational data sharing [
        <xref ref-type="bibr" rid="ref13 ref14">13, 14</xref>
        ]. They implement DSP and the relevant
protocols associated with GAIA-X [
        <xref ref-type="bibr" rid="ref15 ref16">15, 16</xref>
        ].
      </p>
      <p>
        Additionally, the EDC connector features a modular architecture that supports the integration of
extensions. The EDC provides examples and documentation to assist developers in building these
extensions, ensuring that the project can be tailored to meet customer needs. Furthermore, it is
in continuous development and ofers multiple channels for community support, such as GitHub
discussions [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ] and Discord channels [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ].
      </p>
      <p>
        As a result, we chose the EDC solution due to its strong alignment with IDSA RAM 4.0 and DSP, as
well as its ease of extensibility. Furthermore, it uses the Open Digital Rights Language (ODRL) [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]
for the definition of the data access and usage policies, facilitating future interoperability at the policy
level [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ] and supporting future distributed identity management with verifiable credentials.
      </p>
    </sec>
    <sec id="sec-3">
      <title>3. Identity Provider</title>
      <p>One of the focuses of the Health Data Space project is exploring and prototyping methods to provide
participants with identity information. This aspect has significant implications for the security of the
data space, such as ensuring that only authorized users can access the data space ecosystem. This
consideration makes the choice of identity provider an essential factor in technical decisions.</p>
      <p>To ensure a shared understanding in this decision-making process, we outlined the various available
Identity and Access Management (IAM) solutions, examining their implications and their respective
advantages and disadvantages.</p>
      <sec id="sec-3-1">
        <title>3.1. Decentralized Identity and Access Management Solutions</title>
        <p>
          Decentralized Web Nodes (DWN) [21] is a DRAFT 2 specification under development within the
Secure Data Storage Working Group of the Decentralized Identity Foundation (DIF). The EDC Identity
Hub [
          <xref ref-type="bibr" rid="ref22">22</xref>
          ] implemented an early version of this protocol, but that implementation has been deprecated
since EDC version 0.5.0 [
          <xref ref-type="bibr" rid="ref23">23</xref>
          ]. Additionally, DWN focuses on generic credential storage rather than
permission-based access.
        </p>
        <p>
          Decentralized Claims Protocol (DCP) [
          <xref ref-type="bibr" rid="ref24">24</xref>
          ] integrates a complete verifiable credentials flow
into machine-to-machine communication, facilitating the use of verifiable credentials as a distributed
identity management tool for connector communication. However, at the time of the project, the
existing EDC implementation of the protocol lacked support for the issuance component [
          <xref ref-type="bibr" rid="ref25">25</xref>
          ] of the
verifiable credentials flow [
          <xref ref-type="bibr" rid="ref26">26</xref>
          ].
iShare Trust Framework [
          <xref ref-type="bibr" rid="ref27">27</xref>
          ] provides an identity management solution. However, it does
not yet support verifiable credentials and uses a modified OAuth 2.0 flow [
          <xref ref-type="bibr" rid="ref28">28</xref>
          ]. Additionally, the iShare
Trust Framework identifies diferent processes and components to build trust compared to IDSA RAM
4.0.
        </p>
      </sec>
      <sec id="sec-3-2">
        <title>3.2. Central Identity Provider (IdP) Solutions</title>
        <p>
          OAuth using Keycloak (or other IdP that supports Private Key JWT) is a simple solution that
utilizes widely recognized technologies. Keycloak can be configured as an external Identity Provider
(IdP) and supported by the EDC Connector [
          <xref ref-type="bibr" rid="ref29">29</xref>
          ]. However, active development of this solution has
halted within the EDC community. The data space participants also lack direct control over the shared
information since it is managed centrally.
        </p>
        <p>
          OAuth DAPS is listed here for completeness, as only a few implementations have been done,
and none fit the Health Data Space. An OAuth2-DAPS extension has been developed for EDC: Omejdn
DAPS by Fraunhofer, which no longer receives updates [
          <xref ref-type="bibr" rid="ref30">30</xref>
          ]. Sovity has another implementation, but is
tailored for Sovity’s business logic[
          <xref ref-type="bibr" rid="ref31">31</xref>
          ]. To use Sovity’s implementation, the data space participants
need to have a “DAT Mapper”, a custom protocol mapper implemented by Sovity, configured and
assigned to them; this is not the use case for the Health Data Space.
        </p>
      </sec>
      <sec id="sec-3-3">
        <title>3.3. OAuth using Keycloak</title>
        <p>
          OAuth using Keycloak, the most supported toolset by EDC solutions and built on widely accepted
technologies [
          <xref ref-type="bibr" rid="ref32">32</xref>
          ], was selected for implementing the Health Data Space. To enable the configuration,
it is essential to utilize the appropriate EDC extensions, specifically the OAuth 2 Service [
          <xref ref-type="bibr" rid="ref29">29</xref>
          ] and its
associated configurations. We did not choose a distributed solution because no toolset could support
the entire flow of verifiable credentials at the time of the project.
2A DRAFT specification indicates that the specification is a work in progress and is subject to refinement and modification.
        </p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Clearing house</title>
      <p>
        During the implementation of the Health Data Space, a specific requirement emerged from the Flemish
Department of Care: the health authority needs to have transparency of all transactions occurring
within the data space. Furthermore, the authority needs to possess the ability to approve or disapprove
contract negotiations and transfer processes. This aligns with the role of a Health Data Access Body
(HDAB) as defined in the EHDS regulation [
        <xref ref-type="bibr" rid="ref33">33</xref>
        ]. HDABs are responsible for authorizing and issuing data
permits to access electronic health data for secondary use, such as research, policy-making, and other
purposes. This requirement is also consistent with the definition of a clearing house in IDSA RAM 4.0 [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]:
the clearing house acts as an intermediary, providing essential services such as clearing, monitoring
and settlement for all financial and data exchange transactions. These services are performed at various
stages of the data sharing process. Clearing takes place prior to sharing data, and involves verifying
usage contracts specified by means of policies. Monitoring is executed during the actual data exchange,
and comprises logging transaction metadata originating from both data provider and consumer, which
is useful for auditing purposes and resolving possible conflicts. Settlement happens after the sharing of
data, and includes administrative tasks like billing, invoicing and resolving possible conflicts [
        <xref ref-type="bibr" rid="ref34">34</xref>
        ].
      </p>
      <p>
        While the responsibilities of a clearing house in IDSA RAM 4.0 are quite well-defined, their actual
implementation leaves room for debate. As an example, the clearing house interfaces with existing data
space services such as the identity provider and policy enforcement points (PEP) [
        <xref ref-type="bibr" rid="ref35">35</xref>
        ]. However, it can
also ofer services like policy enforcement, enabling data providers to minimize costs by outsourcing
policy enforcement [
        <xref ref-type="bibr" rid="ref34">34</xref>
        ]. The uncertainty and flexibility in how a clearing house should be implemented
may contribute to the lack of ready-to-use clearing house implementations for data spaces in the market,
as stated in [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]. Therefore, a customized clearing house implementation was introduced in the Health
Data Space project, as shown in Figure 2 below.
      </p>
      <p>This extension records events related to contract negotiation and actual data transfers occurring
within the EDC connectors of both the data provider and consumer, hereby ofering monitoring
functionality that can serve as the basis for settlement. The EDC connector is designed as a state
machine, where transactions (both negotiations and transfers) go through a number of well-defined
states (e.g., ‘INITIATED’, ‘STARTED’, ...) so these can be logged.</p>
      <p>
        Additionally, the extension allows to temporarily halt transactions at decision-making moments, and
delegate them to a specialized user interface (UI) component, if specified in the usage contract. While
data sharing in data spaces currently mostly focuses on sending data from one participant to another,
more complex scenarios are possible, but they are all built on peer-to-peer contracts between two
participants [36]. Within the Health Data Space project, the contract triggering external decision-making
includes an ODRL [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ] ‘obtainConsent’ Action, with the clearing house acting as the consenting
party. One could also envision contracts between the participants and the clearing house; however,
this was not considered for the project. The previously mentioned UI component includes buttons as
shown in Figure 3 that facilitate decision making regarding the transaction and subsequently invoke the
connector extension’s callback function to either advance the transaction to the next state or terminate
it, as depicted in Figure 4.
      </p>
      <p>The UI component is identified as the Clearing House in the Health Data Space project, as it provides
monitoring and manual clearing capabilities. In a real-world scenario, this clearing might be more
complex and could, for example, involve the Belgian Health Data Agency (HDA) or another HDAB
checking whether the data sharing complies with regulations. As such, this implementation primarily
served to demonstrate that external decision-making, stretching over an indeterminate duration, is
feasible.</p>
    </sec>
    <sec id="sec-5">
      <title>5. Semantic Interoperability and Vocabulary Hub</title>
      <p>
        Semantic interoperability is a research area that significantly impacts the implementation of data
spaces [
        <xref ref-type="bibr" rid="ref36">37</xref>
        ]. Research work has been done in that domain; for example, the Information Model of the
International Data Spaces (IDS-IM) [
        <xref ref-type="bibr" rid="ref37">38</xref>
        ] is the central integration enabler for semantic interoperability
in any IDS ecosystem [
        <xref ref-type="bibr" rid="ref38">39</xref>
        ], which defines the fundamental concepts that describe actors in a data space,
allowing the data space ecosystem to speak in one language. Data models consisting of ontologies and
schemas are key perspectives that can enhance interoperability.
      </p>
      <p>
        Currently, the only recognized vocabulary service within the Data Spaces Support Centre (DSSC)
toolbox [
        <xref ref-type="bibr" rid="ref39">40</xref>
        ] that features data models is the FIWARE Smart Data Models [
        <xref ref-type="bibr" rid="ref40 ref41">41, 42</xref>
        ]. This model suite
includes a Smart Health perspective, which aligns with the Fast Healthcare Interoperability Resources
(FHIR)3 model. FHIR also has its namespace for the RDF (Resource Description Framework) format [
        <xref ref-type="bibr" rid="ref44">45</xref>
        ].
3Fast Healthcare Interoperability Resources (FHIR) [
        <xref ref-type="bibr" rid="ref42">43, 44</xref>
        ] is a healthcare data standard with an application programming
interface (API) for representing and exchanging electronic health records (EHR).
However, certain limitations are associated with using FHIR in RDF within the Health Data Space.
Notably, no readily available data plane supports FHIR implementations, meaning there is no direct
method to integrate an FHIR server or FHIR client to publish and consume FHIR data through a
connector.
      </p>
      <p>
        The Flemish Smart Data Space (VSDS) [
        <xref ref-type="bibr" rid="ref45 ref46">46, 47</xref>
        ] has a data plane implementation [
        <xref ref-type="bibr" rid="ref47">48</xref>
        ] for linking a
Linked Data Event Stream (LDES) [
        <xref ref-type="bibr" rid="ref48">49</xref>
        ] server [
        <xref ref-type="bibr" rid="ref49">50</xref>
        ] to the EDC connector, complemented by the tool
known as Linked Data Interactions [
        <xref ref-type="bibr" rid="ref50">51</xref>
        ], which facilitates the mapping of data from non-RDF to RDF
formats. In addition, various resources have been onboarded to LDES as listed in the LDES Registry [
        <xref ref-type="bibr" rid="ref51">52</xref>
        ]
and can be shared in the VSDS. Therefore, in developing the Health Data Space, we investigated the
application of LDES to publish health data in RDF format. We experimented with converting the data
from its original format into linked data models in RDF format and subsequently into the LDES using
tools from VSDS. This transformation facilitates data consumption through data space connectors
with existing VSDS blocks. However, as stated in [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], converting health data to the LDES format is
challenging, especially in identifying the proper data model in the medical care domain. Additionally,
using VSDS building blocks requires the installation of the LDES client, which remains an additional
barrier for data providers.
      </p>
      <sec id="sec-5-1">
        <title>5.1. Vocabulary Hub</title>
        <p>
          The Vocabulary Hub serves as a management platform for data schemas within a data space, ofering
schema validation and semantic annotations for various data elements included in the data product4.
TNO’s implementations, the Semantic Treehouse [
          <xref ref-type="bibr" rid="ref53">54</xref>
          ] and the IDS Vocabulary Provider [
          <xref ref-type="bibr" rid="ref54">55</xref>
          ], are two
vocabulary services currently available in the market, each providing a vocabulary hub service at
diferent levels. However, neither service yet supports machine-to-machine integration for communicating
4Data product is a term for data space defined by DSSC Blueprint v2.0 [
          <xref ref-type="bibr" rid="ref52">53</xref>
          ]. A data product typically consists of the resource,
which can be data and/or data service, the description of the resource, its allowed purposes of use, quality, format, frequency,
duration, and other requirements the data product fulfills, access and control rights (e.g., attribution, Intellectual Property
Rights, liabilities, geographical limitations, usability for training LLMs), delivery options (e.g., APIs, SMTP, web interface,
mapping tools), information about data provenance and lineage, pricing and billing information, other information (e.g.,
ethical considerations), and metadata describing all these above.
with the connector.
        </p>
        <p>As previously mentioned, a one-size-fits-all data model does not exist in the medical field. The
standardization of electronic health records is too complex to be addressed within this project’s scope.
As a result, a vocabulary hub for the Health Data Space has not been created. We expect this to happen
with future projects with more health-domain use cases in data spaces.</p>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>6. Metadata Broker and Data Discovery</title>
      <p>
        The Metadata Broker acts as an intermediary between data providers and data consumers and provides
an interface to match data providers with data consumers according to their specific requirements [
        <xref ref-type="bibr" rid="ref35">35</xref>
        ].
      </p>
      <p>
        Several broker products in the market provide diferent methods for harvesting and collecting
metadata. Each product has unique features and approaches to manage metadata efectively. Amundsen,
Atlas, DataHub, Marquez, OpenDataDiscovery, and OpenMetadata are the six popular open-source
data catalogs [
        <xref ref-type="bibr" rid="ref55">56</xref>
        ]. Each available product comes with its advantages and disadvantages. All of these
products fulfill the essential functions required by a Metadata Broker: the ability to expose selected
metadata to designated external parties.
      </p>
      <p>We chose to use Datahub in the implementation of Health Data Space, as imec had developed an
EDC extension: DataHub emitter extension. This extension enables the following process: when a data
product is available in the connector, the extension will emit [57] the metadata of that data product
to DataHub as shown in Figure 5. Once the procedure is completed, the metadata is available on the
DataHub portal as shown in Figure 6.</p>
      <sec id="sec-6-1">
        <title>6.1. Data Discovery</title>
        <p>
          Populating the catalog into DataHub is the beginning of improving data discoverability; several
challenges remain in metadata discovery, particularly regarding machine-to-machine data discovery,
including:
• The metadata populated by the EDC lacks a precise specification, and the fields are not
standardized; this inconsistency makes it dificult for web services to interoperate or harvest the
metadata efectively. For example, within the Health Data Space, integration with the Metadata
Flanders portal [
          <xref ref-type="bibr" rid="ref57">58</xref>
          ] has been explored. This portal automatically harvests data against Data
Catalog Vocabulary (DCAT) standards, but there are mismatches between the fields in the EDC
catalog and those expected by the Metadata Flanders DCAT. Additionally, the EDC metadata does
not provide enough information to be efectively valuable in the portal.
• The current metadata provided by the EDC connector does not include annotations or validations
regarding the sharing or shared data itself, making it challenging to understand the schema
or content of the data. The lack of a vocabulary hub service and a standardized method for
expressing schema across EHR also impacts the current challenge.
• The Linked Data community advocates for using RDF and SHACL [
          <xref ref-type="bibr" rid="ref58">59</xref>
          ] to validate and discover
RDF data; this has also been investigated in the project. It is important to note that not all data
are available in RDF format. In addition, the process of mapping to specific RDF models can be
pretty complex. There is also a significant reluctance among data owners, particularly in the
healthcare sector, to participate in this mapping efort [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ].
        </p>
      </sec>
    </sec>
    <sec id="sec-7">
      <title>7. Conclusion</title>
      <p>
        The Flemish Health Data Space project [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] conducted a technical review of the data space ecosystem
as of 2024. We examined a wide range of available technical resources and components, particularly
focusing on EDC connectors. We successfully built a minimum viable data space that has been deployed
on the customer side. However, several challenges remain in the implementation of a data space.
• Semantic interoperability has been partially achieved at the metadata level but not at the data level.
      </p>
      <p>
        Machine discovery poses extreme challenges due to the lack of unified standards and insuficient
supporting tools. Without secured, accessible toolsets, data owners may lack confidence in
transferring and processing their data, especially in the health sector, where data confidentiality
is paramount.
• The implementation of a clearing house can vary significantly according to requirements, as no
definitive answer is provided by RAM 4.0 [
        <xref ref-type="bibr" rid="ref35">35</xref>
        ] and RAM 5.0 [
        <xref ref-type="bibr" rid="ref59">60</xref>
        ].
• Distributed identity utilizes verifiable credentials for machine-to-machine communication, which
is still in the theoretical specification stage, with tools actively being developed and protocols
being fine-tuned.
      </p>
      <p>
        The challenges mentioned are progressing across various communities and projects. For example,
RAM 5.0 [
        <xref ref-type="bibr" rid="ref59">60</xref>
        ] is evolving within the IDSA working group [
        <xref ref-type="bibr" rid="ref60">61</xref>
        ], while the European Electronic Health
Record exchange Format (EHRxF) [
        <xref ref-type="bibr" rid="ref61">62</xref>
        ] is improving medical record models. Additionally, we are excited
to see advancements in the data space field. Numerous active developments are underway to realize the
Dataspace Protocol, DCAT, and other specifications. Data spaces have gained traction across various
domains, with the Flemish Health Data Space serving as a showcase of this advancement.
      </p>
    </sec>
    <sec id="sec-8">
      <title>Declaration on Generative AI</title>
      <p>During the preparation of this work, the authors used GitHub Copilot in order to: Grammar and spelling
check, Paraphrase and reword. After using these tools/services, the authors reviewed and edited the
content as needed and take full responsibility for the publication’s content.
[36] International Data Spaces Association. IDSA Rulebook: Functional Requirements. 2024. url: https:
/ / docs . internationaldataspaces . org / ids - knowledgebase / idsa - rulebook / idsa - rulebook / 3 _
functional_requirements.</p>
    </sec>
  </body>
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