## 1 Introduction
presented a prototype for which IoT devices own identities that are stored both in a trusted execution environment by their manufacturer and on-chain to guarantee integrity. Following the SSI paradigm, many organizations, such as Trinsic ([[https://trinsic.id/trinsic-ecosystems/#](https://trinsic.id/trinsic-ecosystems/#)]([https://trinsic.id/trinsic-ecosystems/#](https://trinsic.id/trinsic-ecosystems/#)), accessed on 20 May 2024), Connect ([[https://connect.me/](https://connect.me/)]([https://connect.me/](https://connect.me/)), accessed on 20 May 2024), Dock ([[https://www.dock.io/post/self-sovereign-identity](https://www.dock.io/post/self-sovereign-identity)]([https://www.dock.io/post/self-sovereign-identity](https://www.dock.io/post/self-sovereign-identity)), accessed on 20 May 2024), Esatus ([[https://esatus.com/index.html/o3](https://esatus.com/index.html/o3) Fp=7663&lang=en.html]([https://esatus.com/index.html/o3](https://esatus.com/index.html/o3) Fp=7663&lang=en.html), accessed on 20 May 2024), Talao ([[https://talao.co/sandbox/saa4](https://talao.co/sandbox/saa4) ssi]([https://talao.co/sandbox/saa4](https://talao.co/sandbox/saa4) ssi), accessed on 20 May 2024), Veramo [27; 28; 29], and ESSIF ([[https://essif-lab.eu/](https://essif-lab.eu/)]([https://essif-lab.eu/](https://essif-lab.eu/)) (accessed on 20 May 2024) and [30]), have been working on SSI solutions; they have been adopting different underlying technologies and, as a result, have been creating interoperability problems. The effective adoption of these solutions, including also the proposed model, will be possible only after the standardization of all the underlying protocols and the diffusion of the governance models and trust frameworks (Refs. [31; 32; 33]) that have to provide technical, syntactical, semantic and organizational interoperability, as discussed in an interesting work by [PERSON] et al. [34]. The uniqueness of this work is that it presents and promotes a model that, thanks to the SSI paradigm, gives control of individuals' data back to them and aims for deep digitalization in the construction industry and of the all sectors that revolve around it. In addition, it focuses on the digital processes of building design--precisely, on the notarization of the related workflow--but it can be applied to notatize the information flow related to the construction phase of a building and also to the operation, maintenance and demolition phases. Hence, it can be applied to notatize information along the entire lifecycle of a building. The combination of SSI concepts with dApps proposed for notarization of the information flow in CDE allows the exchange of documents with third parties that are not involved in the development of a commission--hence, with individuals that do not have access to the commission CDE--and the verification of the validity of exchanged documents by relying on the proofs left on-chain, as provided by the triangular model of the SSI paradigm in which the holders, issuer and verifier operate. Figure 1 shows the information flow of the proposed model, in which legal and natural persons and buildings (precisely, their owners) interact among each other and with the blockchain and CDE to exchange data/documents as verifiable credentials through the DIDComm protocol, which is a standard for data exchange between DIDs. All stakeholders store data in the CDE, in a digital wallet and on the blockchain, where data are never recorded in plain text.