# Data Exchange

Once participants agree on the meaning of data, they need a secure and reliable way to exchange it. 

Data exchange within a data space typically takes place through APIs, but can also include messaging, data streaming, or algorithm-to-data approaches, and, where relevant, credential exchange mechanisms, depending on the sector and technical setup.

A data space may choose to limit or standardise certain data exchange protocols in its rulebook, while still allowing flexibility where needed. DSSC3.0 makes a clear distinction between:

* Control plane: manages trust, identity, discovery, and access conditions, 
* Data plane: executes the actual transfer of data. 

These layers must work together to ensure that access and usage policies are enforced consistently.

iSHARE does not prescribe a single method for data exchange. Instead, it aligns with and adheres to widely recognised industry standards that ensure interoperability and trust, such as PKI, OAuth 2.0, OpenID Connect 1.0, and Verifiable Credentials (VCs), based on W3C Verifiable Credentials, see more [here](https://dev.ishare.eu/introduction/specific-technical-standards).

When participants use the iSHARE Framework, they automatically operate within these established standards, ensuring that authentication, identification, and authorisation (as defined in the [Data Sovereignty & Trust](https://template.ishare.eu/technical-building-blocks/data-sovereignty-and-trust) pillar) are consistently applied before and after any data flow occurs.

By adhering to open standards and iSHARE trust mechanisms, data exchange across the ecosystem becomes secure, repeatable, and interoperable, making it easier for participants to connect and collaborate across data spaces.

<figure><img src="/files/uysaHlVPeaSodppDENAV" alt=""><figcaption><p>Figure 17. Conceptual Model of the Data Exchange Building Block.</p></figcaption></figure>

DSSC 3.0 also highlights protocol selection, governance, and publication. In practice, this means that the governance framework or rulebook should define how supported data exchange protocols are selected, approved, documented, version-managed, updated, and, where necessary, phased out over time. The protocol specifications themselves should then be published and maintained in a way that makes them findable, accessible, interoperable, and reusable, in line with FAIR principles. This helps create [Synergies of Data Spaces](https://blueprint.dssc.eu/?pane=technical\&technical=best-practice-defining-data-exchange-protocols#Bestpractice%3ADefiningDataexchangeprotocols-5.Synergiesofdataspaces) and enables a network of interconnected ecosystems.

In this context, iSHARE-compliant components play an important role. They can be understood as an implementation of DSSC participant agent services: enabling the actual exchange of data while working together with control-plane functions such as identity, trust, discovery, and policy enforcement. These components secure and govern data exchange across participants, supported by connectors that can be aligned with iSHARE specifications.

{% hint style="info" %}
See the complete DSSC description [here](https://blueprint.dssc.eu/?pane=technical\&technical=data-exchange).&#x20;
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{% hint style="info" %}
Data Exchange connects closely with other building blocks:

* **Data Models:** Provides the technical foundation for formats like JSON.
* **Access & Usage Policies and Enforcement:** Ensures transactions follow access and usage rules.
* **Trust Framework:** Secures transactions through trust protocols.
* **Data, Services, and Offerings Descriptions:** Retrieves the correct version and location of data assets.
* **Value Creation Services:** Defines protocols and versions for data exchange.
  {% endhint %}

{% hint style="warning" %}
The guiding questions can help in the co-creation process and in defining this building block, so please see the next section.&#x20;
{% endhint %}


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