Open call #4

Calling all developers, innovators, researchers, SMEs and entrepreneurs! €1.989.000,00 to support up to 17 projects!

The TrustChain Open Call 4 topic is “Multi chains support for NGI protocols”. The objective of this OC is to design and build the gateways that will make it possible to transfer knowledge/ metadata/ data/ process/ requirements from one chain to another in a trustworthy and secure manner. Interoperability across multiple chains, privacy by design, trustworthiness by design, scalability, greenness, openness, and legal compliance should be carefully considered.

Innovative projects should implement techniques such as:

  • Transfer of Non-Fungible Tokens (NFTs) across different chains. This might include the ability to execute contracts that depend on the state or ownership of an NFT, irrespective of which chain the NFT currently resides on.
  • Semantic standards and open ontology schemas that enable the effective transfer of information and knowledge across chains and allow data interoperability.
  • Mechanisms and procedures that enable the trustworthy use of digital identities across wallets, applications and blockchains or the secure binding of digital identities on multiple chains.
  • Models and procedures to support simple and seamless user experience of cross-chain functionality.
  • Develop techniques to carry out DID rotation and translation so that we can minimize the DID management.
  • Create platforms that can build on top of the existing work that has been undertaken in Open Calls 1, 2 and 3. (Details can be found from the TRUSTCHAIN portal).
  • Develop infrastructures that are inclusive, energy efficient, and usable.
  • Develop platforms and infrastructures that follow European standards.

Applications should cover real needs of the end-users in one a specific sector such as for example banking, education, healthcare, or e-government.

Link with other Open Calls: Understanding what digital identity (Open Call #1) is, data owners privacy policies requirements and data governance (Open Call #2), market mechanisms for data exchange and trading, and federated business models (Open Call #3) is prerequisite for designing and implementing innovative and fit for purpose gateway solutions for cross-chain data exchange. Solutions to be developed in this Open Call #4 should consider some of the approaches and outcomes identified in Open Call #1, #2, and #3. Joint activities between Open Call #1, #2, #3, and Open Call #4 innovators will be facilitated by the TrustChain consortium.

Phases of the Open CALL #4

Proposals are submitted in a single stage and the evaluation process is composed of three phases as presented hereafter:

  • Phase 1: Admissibility & eligibility check
  • Phase 2: Proposals evaluation carried out by the TrustChain Consortium with the assistance of independent experts.
  • Phase 3: Online interviews (10 minutes pitching & 20 minutes of Q&As) and final selection carried out by the TrustChain Consortium and the TrustChain Advisory Board Members.

As part of the TrustChain action, experts in diverse fields will also provide to Third party innovators selected technology development guidance, working methodology as well as access to technical infrastructure, training in business model development and data related topics, coaching, mentoring, visibility and community building support.

Selected projects will last for a duration of 9 months. However, the TrustChain overall action lasts 36 months, and the selected projects are requested to participate after these 9 months in future Joint Meetings for knowledge and know-how transfer to TrustChain OC5 and for the development of the TrustChain ecosystem.


Open Calls will be handled using the F6S platform.

The call is open for submission from May 15, 2024 until July 17, 2024 (17:00 Brussels time). Its indicative budget is €1.989.000,00 with up to a maximum of 17 proposals funded.


The target applicants of this call are developers, innovators, researchers, SMEs, and entrepreneurs working on different NGI relevant topics and application domains at the intersection between the technical field (e.g., Software Engineering, Network Security, Semantic Web, Cryptography, Blockchain, Digital Twin, Blockchain Security, Digital Identity, Blockchain Protocol), the Social sciences and Humanities (e.g., Social Innovation, not-for-profit sector, Social Entrepreneurship, public goods) as well as any others including economics, environment, art, design, which can contribute to the NGI TrustChain relevant vision.

Applicants can apply as individuals or linked to a legal entity. Hence, the participation is possible in several ways:

Team of individuals, all established in any eligible country. This does not consider the country of origin but the residence permit.

One or more entities (consortium) established in an eligible country (see subsection 3.2 of Guidelines for Applicants). The entities can be Universities, Research centres, Non-Governmental Organisations, Foundations, micro, small and medium-sized enterprises (see definition of SME according to the European Commission Recommendation 2003/361/EC), large enterprises working on Internet or/and other related technologies are eligible.

In addition, the following conditions apply:

  • The participating entities should not have been declared bankrupt or have initiated bankruptcy procedures.
  • The entities or individuals (Team of natural persons) applying should not have convictions for fraudulent behaviour, other financial irregularities, and unethical or illegal business practices.


Only Applicants legally established/resident in any of the following countries (hereafter collectively identified as the “Eligible Countries”) are eligible:

Only applicants legally established/resident in any of the following countries (hereafter collectively identified as the “Eligible Countries”) are eligible:

  • The Member States (MS) of the European Union (EU), including their outermost regions.
  • The Overseas Countries and Territories (OCT) linked to the Member States[1];
  • Horizon Europe associated countries, as described in the Reference Documents and the List of Participating Countries in Horizon Europe according to the latest list published by the European Commission.

[1] Entities from Overseas Countries and Territories (OCT) are eligible for funding under the same conditions as entities from the Member States to which the OCT in question is linked.


TRUSTCHAIN was launched in January 2023 to address the inherent challenges within the current centralised Internet architecture that is not transparent to the user, does not protect the privacy-by -default and does not scale well through 5 Open Calls and an overall budget of 8,775 M €.

Learn more about the TrustChain project.

This document is the open call announcement.

This document provides in detail the information to help apply to the TrustChain Open Call 4 such as an abstract of the TrustChain action, a description of the TrustChain Open Call 4, the modalities for application, the evaluation process, the scheme of the funding support, the IPR aspects related to TrustChain and how to prepare and submit a proposal:

The kit also includes the Model Sub-grant Agreement (draft template only), Administrative form (read only), Proposal description and the Additional Applicants templates.


Note: Word templates (Annex D and Annex E) are available at the F6S Submission System.

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