CBDH Practice Questions

Hyperledger Cello is a blockchain provision and operation system, which helps manage blockchain

networks in an efficient way. Cello is a tool that could be used for example by vendors and VARs to

provide a BaaS to their customer base.

Endorsing Peer Endorser peer Peers can be marked as Endorser peer (i.e. Endorsing peer). Upon

receiving the “transaction invocation request” from the Client application the Endorser peer

Validates the transaction. Check certificate details and roles of the requester. Executes the Chaincode

(Smart Contract) and simulates the outcome of the transaction. But it does not update the ledger. At

the end of the above two tasks the Endorser may approve to disapprove the transaction. As only the

Endorser node executes the Chaincode (Smart Contract) so there is no necessity to install Chaincode

in each and every node of the network which increases the scalability of the network.

Peer-to-Peer essentially uses data sharing, hosting hardware owned by many not few, fault tolerant,

secure, lower performance. It’s common way to share files—a good example was Napster. Peer-to-

peer (P2P) file sharing is the distribution of digital media such as software, videos, music, and images

through an informal network in order to upload and download files. Typically, P2P software enables

users to select which files to share. These files are indexed on a central server, making them available

for other users to find and download.

X509 certificates are used in Hyperledger Fabric. An X.509 certificate is any certificate under the

X.509 specification standard for public key infrastructure and Privilege Management Infrastructure

(PMI). The X.509 provides standardized formats for: Attribute certificates Public key certificates

Certificate revocation lists Certification validation algorithms

Hyperledger Fabric includes the REST and JSON RPC APIs, events, and an SDK for applications to

communicate with the network.

Rootcert, tcert and ecert. As The CA (Fabric CA by default) issues a root certificate (rootCert) to each

member (organization or individual) that is authorized to join the network. The CA also issues an

enrollment certificate (eCert) to each member component, server-side applications and occasionally

end users. Each enrolled user is granted an allocation of transaction certificates (tCerts). Each tCert

authorizes one network transaction.

The Infrastructure Module includes the following four modules: Technical, Legal, Marketing, and

Organizational.

Chaincode Interface is required and supports Go, Node.js or Java.

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Invoke is called to update or query the ledger in a proposal transaction. Init is called during

Instantiate transaction after the chaincode container has been established for the first time, allowing

the chaincode to initialize its internal data. Invoke is called to update or query the ledger in a

proposal transaction. Updated state variables are not committed to the ledger until the transaction is

committed.

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Chaincode may be deployed on multiple channels, each instance is isolated within its channel. Each channel maintains their own chaincode and ledger.