# An Empirical Study of a Trustworthy Cloud Common Data Model Using Decentralized Identifiers
## 3 The Extended to Identify Management Scheme for Cloud CDM
### Issuing IRB Credential
Instead of typing in the name, address, and government ID, a presentation of that information is provided from verifiable credentials issued from IRB by an authority trusted by the verifiers, CDM provider, and CDM consumer. The verifiers can automatically accept the claims in the presentation (if they trust the issuer) without any further checking. Instead of obtaining the data directly from the issuer IRB, the data from the issuer comes from the holder, researcher, and the cryptographic material to verify that the authenticity of the data comes from the distributed ledger. This reduces the number of integrations that have to be implemented between issuers and verifiers. A researcher can be issued a professional accreditation credential from the relevant authority (e.g., the College of Physicians and Surgeons) and the claims verified (and trusted) by medical facilities in real time. Should the doctor lose his or her accreditation, the credential can be revoked, which would be immediately in effect. This would hold true for any credentialed profession, be it lawyers, engineers, nurses, tradespeople, real estate agents, and so on. ## 4 Implementation

### Experimental Setup

In this section, the design of the experiments is introduced. Detailed information of our hardware and software configurations is described in Table 2. To run von-network and agents, a docker engine is controlled by those containers. Each of the containers is running as a light-weighted virtual machine. Hyperledger Indy node management is permissioned. It has its own ledger and stores/reads public information in the distributed ledger that is reliably elected. The nodes communicate to agree (reach consensus) on what transactions should be written and in what order. To start Hyperledger Indy nodes, a von-network is used. It is a portable development of Hyperledger Indy with a ledger browser. The von-network plays a role as a Hyperledger Indy public ledger sandbox instance. In this work, it is running in docker locally. Figure 8 shows the von-network with four nodes for identity management in cloud CDM. The von-webserver has a web interface that allows you to browse the transactions in the blockchain. Before issuing a credential, a credential definition as well as its schema needs to be created. Both the schema and the credential definition are recorded on a von-network. Hyperledger Aries Cloud Agent Python (ACA-Py) is a foundation for building a verifiable credential (VC) ecosystem [35]. It operates in the second (DIDComm Peer to Peer Protocol) and third (Data Exchange Protocols) layers of the Trust Over IP framework using DIDComm messaging and Hyperledger Aries protocols in Figure 9. \begin{table}
\begin{tabular}{c c} \hline \hline
**Item** & **Model** \\ \hline CPU & Intel(R) Xeon(R) E-2134 \\ RAM & 16 Gbyte \\ OS & Linux 3.1.0 \\ Docker & 19.03.8 \\ Docker-compose & 1.21.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Hardware and software configuration. A business logic controller is written for the development of a given use case, and the created controller uses the ACA-Py library based on AIP (Aries Interop Profile) 2.0. AIP 2.0 protocols are used for issuing, verifying, and holding VCs that work with a Hyperledger. Indy distributed ledger. The von-network is used to represent a credential format named AnonCreds (Anonymous Credentials). It is a kind of detailed implementation of zero-knowledge proof (ZKP) support. A ZKP is a kind of cryptographic method, and its use in blockchain appears to be promising in cases where existing blockchain technologies can adapt a ZKP to address specific business requirements focusing on data privacy [37]. It proves attributes for an

Figure 8: The von-network running in cloud CDM. Figure 9: Trust over IP framework [36]. entity (a person, organization, or thing) without exposing a correlatable identifier about that entity.