Blockchain Interview Questions Answers

1) What are the many different types of blockchain? Blockchain can be one of the following three categories: Public blockchain Private blockchain Consortium blockchain 2) Is blockchain a transactional database? Blockchain is a diversified database used to store data that works on peer-to-peer network concept rather than transactional database that works on integrity constraint concept. Blockchain is not a database technology like oracle, sql server, mysql, mongodb, postgres etc instead this is a network of servers/computers/machines that are used to store records and all these records are visible to all of the peer machines in this network 3) What is a nonce in a blockchain environment? This is a random 32 bit number that is 4 byte in size. This random number is used only once in blockchain. This unique number is used to create a hash in a blockchain environment. As this is random this is non iterative and not a fixed number. The nonce is present in each and every node in a blockchain environment 4) What nodes form part of ethereum network? Ethereum network is comprised of two types of nodes namely light-weight node,full node. 5) What is a ethereum network? This is a public blockchain network. All decentralized peer-to-peer applications and organizations run with ethereum network as base 6) What are the major projects going under hyperledger umbrella? Following are the projects going under the umbrella a) Fabric b) Burrow c) Iroha d) Indy e) Sawtooth 7) How is cryptocoin price decided? This is determined by demand and supply cycles.It is the market dynamics that determines coin price.As with normal economics id demand is more and supply is less price is high and viceversa 8) Is blockchain a web technology? Nope. Blockchain is not a web technology but rather a network of computers/servers/machines that store records and the records retained are visible to all in the network 9) What are the implementations of distributed blockchain? The implementations of distributed blockchain are primarily used a virtual currency. The implementations include Bitcoin,Ethereum etc. Bitcoin is having a public ledger whereas ethereum is used to create smart contracts 10) Is ripple a implementation of distributed blockchain? Nope. Ripple is an payment, settlement system used by banks, payment providers, digital asset exchanges to transact money globally using an unique distributed consensus mechanism. This is a blockchain designed for banking systems 11) What is bitcoin? Bitcoin is the first implementation of distributed blockchain having a public ledger 12) How many cryptocurrencies are in existence now? More than 1000 cryptocurrencies are available based on blockchain technology having distributed ledger 13) What are the tasks of minors in a blockchain transaction? Minors perform range of tasks including initiate transactions, confirm the transactions 14) What is the unique task of minors? Though minors can initiate a transaction like an user they can also confirm a transaction. Minors are the only ones who can verify the transaction and henceforth this is a major task of minors 15) In a blockchain implementation nodes are users. Can any user initiate a transfer in a blockchain environment? Yes. Any users can initiate a transfer. As far as verification goes only minors can verify transactions 16) Is smart contract constant with ethereum? Nope. Ethereum smart contracts can be programmed as per the needs. Ethereum makes use of the cryptocurrency ether 17) What are the uses of ether? Ether is the cryptocurrency used by ethereum. This is used for paying general transaction and services associated with ethereum smart contracts. It is also used to buy gas. This is again used to pay for computation within the EVM 18) What is nonrepudiation? This is a main assurance in an ethereum network wherein there is an assurance that someone cannot deny something. It This is a random 32 bit number that is 4 byte in size. This random number is used only once in blockchain. This unique number is used to create a hash in a blockchain environment. As this is random this is non iterative and not a fixed number. The nonce is present in each and every node in a blockchain environment 19) What makes blockchain technology more secure? Decentralization makes it more secure. It makes it impossible to corrupt all the miners at the same time owing to de-centralization. High-end cryptographic techniques like RSA and miner's proof of work to enhance security make this possible. Particularly with proof of work miners will have to solve a mathematical puzzle to add a new block in the blockchain. 20) What are some tasks that make use of blockchain technology? Following are some of the tasks that make use of blockchain technology : Track digital assets Create Secure ledger Store immutable data objects Create a public ledger visible to all 21) How many etheres are given as a reward for solving a mathematical puzzle in a ethereum blockchain? In ethereum 5 etheres are given as reward for solving a mathematical puzzle 22) Has ethereum blockchain been hacked atleast once? Nope. Ethereum blockchain has never been hacked. However, the smart contract had vulnerability 23) Give details on what is a blockchain client :- Blockchain client is a software that : a) Verifies the transaction b) Executes the blockchain protocol logic c) Has the responsibility for generating the transactions as per the instructions d) Is being used by nodes and miners to connect to the blockchain network 24) What is the cryptocurrency used in ethereum network? What is its use? It is the ether that is being made use of by ethereum network. It becomes necessary to be paid for every operation performed in a ethereum blockchain for which ether is used 25) What is a hash rate? The speed at which a compute is completing an operation in a bitcoin code is referred to as hash rate. 26) What hashrate is better during mining? Higher hasrate is recommended 27) What is the blockchain that is designed for internet of things? IOTA is designed for internet of things 28) Is it necessary to trust admin/root to trust the data in blockchain? If not whom to trust? No need. It is not necessary to trust admin/root to trust data in blockchain. It is necessary to trust the centralized ledger/brand. 29) What happens when a centralized ledger/brand is trusted? It is equivalent to trusting the brand who owns the inventory. This trust is essential rather than trusting admin/root which happens to be typically CEO or owner of the brand who claims that technology being used is safe and secure 30) What is multichain? It is a blockchain in itself. 31) Is multichain related to bitcoin? It is neither related to nor extended version of bitcoin 32) Which conflict resolution rule is used to resolve conflicts in public blockchain? Longest chain rule is used for conflict resolution in public blockchain