CBDH Exam Dumps - Blockchain Developer - Hyperledger Fabric Questions and Answers

Explanation

Representation of current state of the assets. Asset state data can be changed upon changes to the state of the data. • Transaction Logs: Record of all the transactions (in the order they are received) which modified the state data, and once the data is written it is immutable and cannot be changed.

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Orderer Ordering services handles the main function of the Hyperledger Fabric to maintain consistency in the transactions processes. Ordering services provides a shared communication to clients and peers and helps in broadcasting the messages containing transactions.

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.

Chaincode is a decentralized transactional program, running on the validating nodes. As with every chaincode, it implements the Chaincode interface in particular, Init and Invoke functions. 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.

Let’s have a closer look at the structure of a block. It consists of three sections Block Header This section comprises three fields, written when a block is created. Block number: An integer starting at 0 (the genesis block), and increased by 1 for every new block appended to the blockchain. Current Block Hash: The hash of all the transactions contained in the current block. Previous Block Hash: A copy of the hash from the previous block in the blockchain.

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