## 3 The SSI-Based Identity Management
### Applying SSI Model to Cloud CDM  
According to the fundamental SSI model, the personalization agency issues and submits users' identity information in advance so they can acquire the requested service from the verification agency [20]. The certificate of the personalization agent is kept in a verified data registry to guarantee the accuracy of the identification information issued by the personalization agent. When a verification body receives the identification documentation, it authenticates it in the register and offers services. A credential is a group of assertions made up of one or more attributes, such as a name or a resident identification number, that the issuer can verify. It is a declaration of authority, qualification, or competence made to an entity (e.g., an individual or organization) by a third party who has the necessary de jure authority or competence. An IRB must assess and approve any research involving human subjects or that is subject to FDA regulation. Before beginning any human subject research projects, it is the duty of all researchers to obtain IRB permission or exempt determination in a cloud CDM. The capability-based trust paradigm for a cloud CDM is depicted in Figure 4. Verifiers are the CDM provider and the CDM customer. With no verifiable credential (VC) granted by IRB, the verifiers may not be able to fully trust the researcher and may act as an entity to release only a portion of the data or to respond to a request for data via the cloud CDM. They might also wish to provide the researcher access to certain data subsets. As  
Figure 3: The is based on SSI-based Identity Management in a cloud CDM. evidence of the researcher's aptitude, the proof assembled from a portion of VC is used. The permission granted by the proof may have to be withdrawn, amended, or put on hold. Table 2 summarizes the qualitative comparison of the characteristics of the baseline CDM model and the proposed cloud CDM model. In terms of the fault tolerance, data sharing, privacy, and data integrity, it can be seen that the proposed cloud CDM model is improved over the baseline CDM model. There are three entities, IRB, CDM provider, and CDM consumer, in Figure 5. Each of those entities has a public DID that is published globally. The IRB acts as a verifiable credential issuer for a researcher. The identity of the issuer (via the public DID) in the credential ought to be part of what the verifier discovers from the presentation, because the researcher, as the bearer of the credential, may show the credential to anybody. The verifier might investigate to determine whether they believe the issuer. IRB's public DID is placed on a blockchain in order to be resolved globally. It is used to provide secure point-to-point communication channels between the participants' agents. DIDs are used as the identification for IRB as the issuer in the cloud CDM and have a verifiable credential. A public key associated with the DID is obtained by resolving the IRB (the issuer) DID, which is used to specifically identify the issuer. The information in the verified credential is then used with that public key to confirm that it did indeed originate from the issuer. This public DID guarantees that the verifier is aware of the source of the credential that the holder is presenting. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **The Basic CDM Model** & **The Proposed Cloud CDM Model** \\ \hline Security & There is no access control mechanism & Supporting high security with access control by verifiable credential \\ \hline Privacy & The exposure of CDM data ownership & Enhanced secure DID ownership \\ \hline Data integrity & Vulnerability of CDM data integrity & Ensuring data integrity with cryptography \\ \hline Data sharing & There is no data-sharing policy & Providing a data-sharing policy through proof and verification by verifiable credential \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Qualitative comparison of CDM models. Figure 4: The capability-based trust model for a cloud CDM.