What is an interoperability node in Gaia-X?

Gaia-X represents an innovative paradigm for linking data more closely to the technological infrastructure underneath, so as to ensure the transparency, origin and functioning of these resources. This model allows us to deploy a sovereign and transparent data economy, which respects European fundamental rights, and which in Spain will take shape around the sectoral data spaces (C12.I1 and C14.I2 of the Recovery, Transformation and Resilience Plan). These data spaces will be aligned with the European regulatory framework, as well as with governance and instruments designed to ensure interoperability, and on which to articulate the sought-after single data market.

In this sense, Gaia-X interoperability nodes, or Gaia-X Digital Clearing House (GXDCH), aim to offer automatic validation services of interoperability rules to developers and participants of data spaces. The creation of such nodes was announced at the Gaia-X Summit 2022 in Paris last November. The Gaia-X architecture, promoted by the Gaia-X European Association for Data & Cloud AISBL, has established itself as a promising technological alternative for the creation of open and transparent ecosystems of data sets and services.

These ecosystems, federated by nature, will serve to develop the data economy at scale. But in order to do so, a set of minimum rules must be complied with to ensure interoperability between participants. Compliance with these rules is precisely the function of the GXDCH, serving as an "anchor" to deploy certified market services. Therefore, the creation of such a node in Spain is a crucial element for the deployment of federated data spaces at national level, which will stimulate development and innovation around data in an environment of respect for data sovereignty, privacy, transparency and fair competition.

The GXDCH is defined as a node where operational services of an ecosystem compliant with the Gaia-X interoperability rules are provided. Operational services" should be understood as services that are necessary for the operation of a data space, but are not in themselves data sharing services, data exploitation applications or cloud infrastructures. Gaia-X defines six operational services, of which at least two must be part of the mandatory nodes hosting the GXDCHs:

Mandatory services

• Gaia-X Registry: Defined as an immutable, non-repudiable, distributed database with code execution capabilities. Typically it would be a blockchain infrastructure supporting a decentralised identity service ('Self Sovereign Identity') in which, among others, the list of Trust Anchors or other data necessary for the operation of identity management in Gaia-X is stored.
• Gaia-X Compliance Service or Gaia-X Compliance Service: Belongs to the so-called Gaia-X Federation Services and its function is to verify compliance with the minimum interoperability rules defined by the Gaia-X Association (e.g. the Trust Framework).

Optional services

• Self-Descriptions (SDs) or Wizard Edition Service: SDs are verifiable credentials according to the standard defined by the W3C by means of which both the participants of a Gaia-X ecosystem and the products made available by the providers describe themselves. The aforementioned compliance service consists of validating that the SDs comply with the interoperability standards. The Wizard is a convenience service for the creation of Self-Descriptions according to pre-defined schemas.
• Catalogue: Storage service of the service offer available in the ecosystem for consultation.
• e-Wallet: For the management of verifiable credentials (SDs) by participants in a system based on distributed identities.
• Notary Service: Service for issuing verifiable credentials signed by accreditation authorities (Trust Anchors).

What is the Gaia-X Compliance Service (i.e. Compliance Service)?

The Gaia-X Compliance Service belongs to the so-called Gaia-X Federation Services and its function is to verify compliance with the minimum interoperability rules defined by the Gaia-X Association. Gaia-X calls these minimum interoperability rules (Trust Framework). It should be noted that the establishment of the Trust Framework is one of the differentiating contributions of the Gaia-X technology framework compared to other solutions on the market. But the objective is not just to establish interoperability standards, but to create a service that is operable and, as far as possible, automated, that validates compliance with the Trust Framework. This service is the Gaia-X Compliance Service.

The key element of these rules are the so-called "Self-Descriptions" (SDs). SDs are verifiable credentials according to the standard defined by the W3C by which both the participants of a data space and the products made available by the providers describe themselves. The Gaia-X Compliance service validates compliance with the Trust Framework by checking the SDs from the following points of view:

• Format and syntax of the SDs
• Validation of the SDs schemas (vocabulary and ontology)
• Validation of the cryptography of the signatures of the issuers of the SDs
• Attribute consistency
• Attribute value veracity.

Once the Self-Descriptions have been validated, the compliance service operator issues a verifiable credential that attests to compliance with interoperability standards, providing confidence to ecosystem participants. Gaia-X AISBL provides the necessary code to implement the Compliance Service and authorises the provision of the service to trusted entities, but does not directly operate the service and therefore requires the existence of partners to carry out this task.