Blockchain MCQ's Question Bank
Blockchain MCQ's
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NPTEL BLOCKCHAIN ASSIGNMENT
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Week 1
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1. Which of the following are properties of Blockchain?
Accepted Answers:
- All of the above
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2. A block in blockchain is pointed using:
Accepted Answers:
- Hash Pointer
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3. The property of consistency is preserved in blockchain by maintaining -------
Accepted Answers:
- A Local copy of the Global Information
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4. Authentication codes for messages are also known as:
Accepted Answers:
- Keyed Hash Function
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5. Suppose, you develop a system using RAFT consensus protocol. Using the consensus mechanism, your system identifies that the leader is Byzantine. What will the system do now?
Accepted Answers:
- This scenario will not happen
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6. Suppose, we have designed a new RSA algorithm with ΓΈ(91)=91* pi (1-1/p), keeping all other parameters as actual RSA algorithm.
If the decryption key is 29, the encryption key is:
Accepted Answers:
- 5
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7. Suppose. you and your friends have a few numbers of locks and you all want to share that numbers among yourselves securely using RSA based cryptosystem You are using the private key as (5,27) and your friends are using the public key as (13,27) One of your friends wants to share the exact amount of locks only to you. What are the maximal possible locks that your friend can have so that he/she can secretly share that to you?
Accepted Answers:
- 26
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8. Suppose, an attacker gets access to the ciphertext which is 8 and public key (13,27). Keeping the other parameters Same as the previous question, can the attacker guess the original message?
Accepted Answers:
- Yes
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9. Which is used for signing the message digest in the public-key cryptosystem?
Accepted Answers:
- using the private key of the sender
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10. Which is/are the example/s of the double-spending attack?
Accepted Answers:
- Alice has a total of 40 unspent bitcoins from two different transactions with an equal amount of bitcoins each. She sends the entire amount each to
Dick and Tom from one of the transaction
- Bob brought a car using x bitcoins. On delivery the bitcoins are transferred from his wallet to the shopper's wallet. Simultaneously, he uses that bitcoins
for another purchase
- Bob has 20 unspent bitcoins. He sends the entire amount each to Dick and Tom
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11. Which of the following bitcoin scripts wil generate a TRUE outcome?
i) scriptSig: <sig scriptPubKey: <pubKkey> OP DUP OP HASH256<pubKeyHash> OP EQUAL OP_VERIFY, OP_CHECKSIG
ii) scriptSig: <pubKey> scriptPubKey: OP_HASH160<pubKeyHash> OP EQUAL
iii) scriptSig spubKey scriptPubkey: <pubKey OP_EQUALVERIFY
iv)scriptsig: <sig> scriptPubKey: <pubKey> OP_CHECKSIG
Accepted Answers:
- i, ii, iv
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12. Which of the Select the script which checks the equality of the hash values:
Accepted Answers:
- <data1> <data2> OP_SHA256 OP_SHA256 OP_SWAP OP_HASH256 OP_EQUAL
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13. What is/are the content(s) of the block header in bitcoin?
Accepted Answers
- Merkle root
- Target threshold nBits
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14. Suppose 15 trustworthy nodes are performing some task distributedly As per the process,at a certain level, at a every node of the team shares the results for making the consensus. After starting the task, 7 trustworthy nodes drop the plan and they are replaced by 7 other nodes whose trustworthy information is unknown. After joining the new nodes, some discrepancy occurs in the system, although all the nodes are running correctly without any software or hardware error. What is the type of fault it is in the context of distributed consensuS?
Accepted Answers:
- Byzantine Fault
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15. In distributed consensus, all the correct individuals either reach a value or null. What is the name of the property?
Accepted:
- Answers Integrity
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Week 0
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1.Who created Bitooin?
Accepted Answers:
- Satoshi Nakamoto
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2.Where do you store your cryptocurrency?
Accepted AnswerS:
- Walet
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3.What is a blockchain?
Accepted AnswerS:
- A distributed ledger on a peer to peer network
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4.What is a hash function?
Accepted Answers:
- Takes an input of any length and retuns a fixed-length string of numbers and letters
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5.Blockchain is the same as Bitcoin?
Accepted Answers:
- False
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6.What is the process of creating new bitcoins popularly known as?
Accepted Answers:
- Mining
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7.Are blockchain fully public?
Accepted Answers:
- it depends
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8) What does the block in the blockchain consist of?
Accepted Answers:
- Transaction data
- A Hash point
- A Timestamp
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Week 3
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1) In public key cryptosystem based digital signature, the message digest is signed by:
Accepted Answers:
- sender's private key
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2) In crypto-currency a ledger records?
Accepted Answers:
- list of transactions
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3) a. What defines a valid ledger?
b. Given a valid ledger can you generate account balances ?
Accepted Answers:
- a.All transaction are valid b. Yes
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4. Repudiation/ verifiability problem can be solved by digitally signing transaction by sender in Blockchain?
Accepted Answers:
- true
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5) When will replay attack happen?
a. Sender Account balance after transaction is greater than or equal to the amount transferred in the transaction.
b. "Change Address" is included in the transaction
c. Sender Account balance after transaction is less than the amount transferred in the transaction.
Accepted Answers:
- a.Yes b.No c.No
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6) Fischer-Lynch-Paterson impossibility result: consensus is impossible with even a single faulty node?
Accepted Answers:
- true
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7) Which of the following is/are decentralised system?
Accepted Answers:
- Bitcoin
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8) Why consensus is hard?
Accepted Answers:
- No notion of global time
- faults in network
- nodes may crash/ faulty nodes
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9) Paxos is?
Accepted Answers:
- Consistent
- rarely stuck
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10) is Byzantine General Problem solvable for 3 nodes?
Accepted Answers:
- false
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Assignment 3
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1.Say, at some instance three independent miners propose the following three blocks
(containing the transactions enclosed in [])
B1=[T100, T102, T104, T105],
B2=[T100,T102,T103],
and B3=[T100, T102,T103,T104,T105].
If the consensus algorithm is Proof of Work (PoW). Which of these block likely to get included in the
chain once the network achieves consensus, given the last block in the blockchain has transactions
T98, T99 and T101?
B1
B2
Accepted Answers:
- Each of these blocks have equal chances to get added to the blockchain
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4.Considering the Proof of Elapsed Time (PoET) adapted in Hyperledger Sawtooth
framework, which of the following mechanisms is used to ensure that the miner (or block leader) is a legitimate participant and not an attacker and has waited for the random amount of time assigned by the network?
Accepted Answers:
- By ensuring that the trusted regions of the code are run in Trusted Execution Environments (TEE) and the user cannot tamper it
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5.Suppose at a given instance the difficulty set by the BitCoin network is 56, with the last
2016 blocks mined in 11 days. What will be the next computed value of the difficulty [use ceiling to round off to the next integer]?
Accepted Answers:
- 72
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6. WIth mining pools in effect, which of the following problem or problems may appear in the
Accepted Answers:
- Monopoly in mining
- Discouragement among miners to fully complete the task posed by the network
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7. What are the primary assumptions behind a permissioned blockchain network?
Accepted Answers:
- Users are known apriori
- The network is closed
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8. Which of the following ensure ordered sequential execution of transactions in a permissioned blockchain network?
Accepted Answers:
- The underlying consensus algorithm
- The broadcasted state information
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9. Suppose in a distributed network, running Paxos as the underlying consensus algorithm,
has 3 proposers and 5 acceptors and 1 learner. Say, 3 of the acceptors have failed, which of the following is true about the network?
Accepted Answers:
- None of the proposers get a reply
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10)Say, 5 nodes (with ids 1..5) contribute to a distributed system. During the process of
reaching consensus, a proposal is suggested by node 4 with a proposal number 103. In similar fashion, a proposal is suggested by node 3 with a proposal number 111. Node 2 being a malicious node immediately makes another proposal with a proposal number 117. What will be final state of the system after the consensus is reached (consider PAXOS as the underlying consensus algorithm)?
Accepted Answers:
- Blocking proposal 117 and accepting proposal 111 finally
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Week 5
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1) Which of the following entities in Hyperledger Fabric executes the chaincode (smart contract)?
Clent Application Node
Committing Peer Node
Endorsing Peer Node
Orderer Node
Accepted Answers: Endorsing Peer Node
2) Which of the following does NOT happen during the endorsement step by the endorsing peer in the flow for Hyperledger Fabric?
Execution of proposed transaction
Creation of read/write set based on execution
Signing and encryption of transaction response
Updation of ledger
Accepted Answer: Updation of ledger
3) Which of the following is the appropriate syntax for declaring an endorsement policy with either any admin from organization ABC or a combination of any member from organization CDE and any admin from organization DEF
-p "AND('ABC.member' 'DEF.admin')"
-p "OR('ABC.member', 'CDE. admin')"
-P "OR"('ABC.admin', OR('CDE.member','DEF.admin'))"
-p"OR"('ABC.admin', AND('CDE.member', 'DEF.admin'))"
Accepted Answers -P "OR"('ABC.admin', OR('CDE.member','DEF.admin'))"
4) Which of the following abstractions in Hyperledger Fabric provide confidentiality to individual ledgers ?
Ordering Services
Peers
Channels
Endorsement Policies
No, the answer is incorrect. Score: 0
Accepted Answers: Channels
5) Suppose there are 5 channels present in a Hyperledger Fabric network, each of them has access to 3 chaincodes A, B and C. How many
containers will run in each peer for running this system?
5
1
3
15
Accepted Answers:3
6) Which of the tollowing functions must be performed by the client application in Hyperledger Fabric to ensure that a
transaction is successfully added to the blockchain?
Accepted Answers:
- Creating of transaction proposal and sending it to endorsing peers
- Receiving signed proposal responses and sending to ordering service
- Receiving block events from peers
7) Running a chaincode on hyperledger fabric involves the following steps
i.Instantiation of Chaincode of Channel
ii. Creation of Channel
iii. Configuring Orderer and Peer nodes
iv. Adding members to Channel
v.Installing chaincode on peers
Which of the following sequence of steps is valid?
Accepted Answers
iii, v, ii, iv,i
8) Fabric CA or External CA can provide identities for which of the following?
Accepted Answers:
- Adnistrators
- Peers
- Orderers
- Client Applications
9. which of the following functions are supported by Fabric CA
Accepted Answers:
- Clustering for HA characteristics
- Integration with LDAP for user authentication Configuration to use HSM for security
10)Hyperledger v1 does NOT support writing of chaincode in which of the following languages?
Golang
Javascript
Python
Java
Accepted Answers: Python
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Week 8
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1) Blockchain in Energy Markets helps in the following ways
Accepted Answers:
- Provides a single view of demand and supply of power
- Provides secure and real time updates of the energy consumption data.
- Ensures reduction in errors in the generation of electricity bill.
2) How is energy assetized in GridChain?
Accepted Answers:
- It is done by using a crypto token
3) What are the advantages of using blockchain tor GST collection?
Accepted Answers:
- Automatic tax payment to the tax authority
- Tamper proof invoice generation based on the taxes already levied
- Transactions are done in real time
4) How does the blockchain ensure the tamper-proof of the data in defence scenarios?
Accepted Answers:
- The transaction infomation written once in the system, cannot be modified in the blockchain.
5) Why a blockchain based solution is suited for managing govemment data at different levels?
Accepted Answers:
- Provide different role-based acoess policies across different levels of the organization hierarchy in a multi-authoitative setup
- Provide classification of data based on importance even ina decentralized environment
- Provide a way to access the data only via the blockchain
6) How does Blockchain based solution adhere to the principles of Digital ldetity Maragement?
Accepted Answers:
- Proides secure and restricted acoess to the digital identity
- Provides a loging mechanism to track acoess to the digital identity
7) Which of these is not a valid example of identity traud?
Accepted Answer: Acadermic institute accesses their students curent academic record.
8) How does storing data in Blockchain help in Audit and Compliance use case?
Accepted Answers:
- Any changes to the data will be logged in the blockchain
- Records can be aggregated from multiple departments.
9) Who would be the Blockchain network consortium members in the Citizen ldentity solution?
Accepted Answers:
- Record Keeping Agencies
- Govemment ldentity Providers
10)What data should be part of the biockchain ledger for property transactions?
Accepted Answers:
- Propety records (all olearance certifticates etc) along with proof of ownership.
- Bank acoount details of the buyer and seller.
- Sale Deed of the property
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Week 10
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1 Which of the following private information is stored by SideDB when using levelDB
Answers:
- Only key/ value pair set
2) How is data validation perfomed in Side DB?
Answers:
- The private read-write set contains the hash of the keys, and the version corresponding to them is checked
3) PoW is scalable in terms of the foliowing
Answers:
- Node scalability Number of clent support
4) Total ordering is ensured in the following protocol/s:
Answer:
- RAFT
5) What is the intormmation used for generating the micro blocks in the Bitcoin-NG?
Answers:
- Publc key
6) How does the previous block reference in each key biock of Bitcoin-NG?
Answers:
- Either previoUs key biock or microbliock
7) In case of collective signing, if the system allows at most f false witnesses, then what is the minimum number of true cosignature required on the statement for ensuring the honesty in the system?
Answers:
- t+1
8) How does Bitcoin NG handie the micro blook fork?
Answers:
- Moro blocks are aded only after waiting for the propagation time of the network
9) How many private values are used by each signer in Schnor Multisignature?
Answers:
- Two
10) Consider the folowing blockchain in Byzcoin with sliding window size 9. The ID in each block indicates the miners 1 point 1D that has mined that block
Answers:
- (M6 M4 M2 M1)
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Week 11
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1) Which of the following paradigms of query construction is accepted over BigchainDB?
ANS
- MongoDB Query (a kind of NosQL)
2) Say, for a decentralized Al service there are four modules (Or Al services) of video processing, audio analysis, speech prOcessing and
Answers
- Service Wrapper APl
3) Which of the following strategies are used to manage the scalability of the Byzantine Agreement in the Algorand
Answers
- Selecting a specific number of nodes to fom the random committee
4) Which of the following is true about the selection of the random committee in the Algorand network?
Answers
- The nodes elect themselves as a committee member by winning a local computation
5) Say, in a standard Algorand networka user j has a weight k (number of Algorand units possessed by the user j) and the overall weight considering all the users in the network is K. Which of the following is proportional to the probability of the jth user to be chosen by the cryptographic sortition algorithm?
Answers
- kj/K
6) Considering the cryptographic sortition function for the selection procedure which of the following arguments of the function ensures that the of the random committee change in every iteration
Answers
- seed: A publicly known random value
7) Algorand maps each of the units (analogous to coins in BitCoin) held by a useri as a "sub-user.
Answer
- wiCk p(1-p)*
8) Referring to the previous question, which of the following represents the probability distribution for choosing exactly
Answers
- Binomial Distribution
9) Considering the "Automated Smart Contract Generation" Technology in Matrix Al, which of the following is facilitated by the use of
Answers
- Code Generation
10)Which of the arguments of the cryptographic sortition function, for the selection procedure, ensures that the members of the random
Answers
- seed: A publicly known random value
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Week 12
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1) What are the different consensus mechanisms supported by Ethereum Virtual Machine?
a. Proof of Work
b. Proof of Stake
c. Practical Byzantine Fault Tolerance
d. Proof of. Elapsed of Time
ANS - a, b
2) Which of the following is not a true statement about the Ethereum architecture?
a. Every node runs the Ethereum execution environment (EVM)
b. When a node receives a block, the EVM runs some but not all transactions specified in the block.
c. Mining is based on PoW, PoS.
d. Sharding helps improve scalability by having nodes hold a subset of the state and validate only a sub
ANS - b
3) Which of these are Ethereum clients?
a. Geth
b. Trinity
c. Parity
d. Mocha
ANS - a,b,c
4) What are the components needed to build an Ethereum DApp?
a. Smart Contract
b. Wallet
c. Ethereum Client
d.Virtual Machines for Mining
ANS - a, b, c
5) Quonum supports transactions with:
ANS
- Either private or public state for a transaction
6) Which of the following statements are true regarding Quorum chain consensus?
ANS
- It can be replaced with other BFT consensus implementations in Quorum Most recent block with maximum number of votes is the canonical head
7) Which of the blockchain implementations are mapped to the correct state machine model
ANS
- Corda UTXO,
- Ethereum-Account/Balance Model,
- Bitcoin UTXO
8) What are implementation differences between Corda and Ethereum?
ANS
- State machine model,
- Support for native currency,
- Consensus mechanism used
9) In Corda, the transaction flow consists of the following steps (not necessarily in the listed order):
ANS
- Signatures are created with the hash of the transaction,
- Update the ledger by marking zero or more existing ledger states as historic (the inputs),
- Transaction finality is reached when the specified notary service signs the transaction
10)Which of the following are true about the notary in a CORDA network?
ANS
- Notary maintains a map of transaction IDs used as input. - Many notaries can exist in a network
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Merkle tree hash is used for computing _________ hash.
a. state root
b. transaction root
c. receipt root
d. all of the above
ANSWER: D
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Double spending is reusing digital assets intentionally or inadvertently. True or False?
a. True
b. False
ANSWER: True
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The _____ can send transactions for ether transfer or they can send transactions to invoke a smart contract code.
a. block headers
b. algorithms
c. accounts (address)
d. blocks
ANSWER: C
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Who introduced the digital online cryptocurrency known as Bitcoin?
a. Satoshi Nakamoto
b. Wei Dai
c. Nick Szabo
d. Hal Finney
ANSWER: A
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Trust in a decentralized blockchain is about ______________.
a. validating the transactions and blocks for tamper proofing.
b. All of the above
c. securing the chain using specific protocols.
d. executing and confirming the transactions.
ANSWER: B
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Trust in _________ is the ability to handle natural exceptional situations such as a chain split and double spending.
a. smart contracts
b. mining
c. robustness
d. Proof of Work
ANSWER: C
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Proof of work is the __________ used by Bitcoin blockchain and Ethereum Byzantium Metropolis blockchain.
a. Transaction confirmation
b. Consensus Protocol
c. Incentive function
d. Trust function
ANSWER: B
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___________ hosts the software needed for transaction initiation, validation, mining, block creation, and smart contract execution.
a. EVM
b. Ethereum full node
c. External Account
d. Smart Contract
ANSWER: B
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After a hard fork, the emerging two chains are incompatible. True or False?
a. False
b. True
ANSWER: True
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What allows for the execution of code in the Ethereum Blockchain, enhancing the basic value transfer capability of the Bitcoin Blockchain?
a. Ethereum Virtual Machine Proof-of-Work
b. Smart Contracts
c. Solidity
d. Byte-code
ANSWER: B
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Which one of the following is correct?
a. A secure blockchain is a single chain in an inconsistent state.
b. There is only one, single criteria measured to perform validation.
c. Neither timestamp nor nonce can be verified.
d. Once a consensus is met, a new block is added to the chain.
ANSWER: D
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For the simple symmetric key example discussed in the lecture, it is easy to derive the “secret” key from the encrypted data. True or False?
a. False
b. True
ANSWER: True
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A transaction generates new UTXOs for transferring the amount specified in the input UTXOs. True or False?
a. False
b. True
ANSWER: True
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What type of hash function is used, when there is a variable number of items to be hashed, such as the many state changes in a block?
a. Simple Hash
b. Tree-structured Hash
c. Either
d. Complex hash
ANSWER: B
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Miners are computers that execute ___________________.
a. operations defined by users
b. operations defined by the blockchain protocol
c. operations defined by transactions
d. None
ANSWER: B
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In a public blockchain, a participant can join and leave the blockchain as and when they wish. True or False?
a. True
b. False
ANSWER: True
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Digital signing of a transaction/document involves, hashing the content of the document and then __________.
a. encrypting it with nonce
b. rehashing it
c. encrypting it with public key
d. encrypting it with private key
ANSWER: D
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Miners execute the transactions for Ether transfers but are not responsible for the execution of smart contracts. True or False?
a. False
b. True
ANSWER: False
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256 bit ECC key-pair is equivalent in strength to approximately 3072-bit RSA key-pair. Thus ECC is much stronger encryption than RSA method. True or False?
a. True
b. False
ANSWER: True
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The transaction Merkle Tree root value in a Bitcoin block is calculated using ______________.
a. previous block’s hash
b. none
c. hash of transactions
d. number of transactions
ANSWER: C
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True or False? Proof of work is an agreed-upon method by which the creation of a new block is achieved in the Bitcoin blockchain.
a. False
b. True
ANSWER: True
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GASLIMIT is the actual amount of gas spent at the completion of the Block creation. True or False?
a. True
b. False
ANSWER: False
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What is the smallest denomination of cryptocurrency on Ethereum?
a. Ether
b. Bitcoins
c. Wei
d. Gas Point
ANSWER: C
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Validation, Verification, Immutable Recording, and ____________ lead to Trust and Security.
a. Coins
b. Algorithms
c. Tokens
d. Consensus
ANSWER: D
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Transaction 0 in every block in the bitcoin blockchain ______________.
a. is for paying the miner fees
b. does not have any input UTXO
c. is called the coinbase transaction
d. All of the above
ANSWER: D
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In Ethereum, the block hash is the hash of all the elements in the _________________ .
a. Transaction hash tree
b. Block header
c. State tree
d. Receipt tree
ANSWER: B
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Bitcoin blockchain implemented a soft fork to realize a ______________.
a. Split into Bitcoin core and Bitcoin cash
b. P2SH Peer-to-Shell feature
c. P2SH conditional payment script feature
d. P2SH payer gossip feature
ANSWER: C
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In Ethereum, a combination of account number and global nonce is used to address issues regarding double spending. True or False?
a. False
b. True
ANSWER: True
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What happens if more than one miner solves the consensus puzzle very close in time to each other in Ethereum?
a. The new block is added to the main chain and not the runner-up chain
b. Runner-up miners leave the network.
c. Small incentives are given to runner-up blocks
d. Small incentives are given to the runner up blocks and the new block is added to the main chain
ANSWER: D
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Did Bitcoin enable a centralized or a decentralized system for exchange of value? [CO-5]
a. Centralized
b. Decentralized
ANSWER: B
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What are miners who solved the puzzle but didn't win the block creation called? [CO-2]
a. Sisters
b. Cousins
c. Brothers
d. Ommers
ANSWER: D
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How many types of accounts are on Ethereum?
a. 1
b. 3
c. 2
d. 4
ANSWER: C
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What does UTXO stand for?
a. Unique Transaction Offer
b. Unspent Trade Offer
c. Unspent Transaction Xeroxed Output
d. Unspent Transaction Output
ANSWER: D
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If a participant node tampers with a block, it results in _____________.
a. hash changing
b. mismatch of hash values
c. the local chain of node rendered in an invalid state
d. All of the above
ANSWER: D
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Keccak 256 is a commonly used algorithm for hash generation in Ethereum blockchain. True or False?
a. False
b. True
ANSWER: True
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A popular public-private key implementation known as Rivest-Shamir-Adelman (RSA) algorithm is used for the Bitcoin and Ethereum Blockchain. True or False?
a. True
b. False
ANSWER: False
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Block hash allows for the formation of the chain link by embedding the previous block hash in the current block header. True or False?
a. False
b. True
ANSWER: True
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Any changes to the value of a state variable in a smart contract are stored on the blockchain. True or False?
a. True
b. False
ANSWER: True
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_________ is paid fees for the creation of a block.
a. Receiver of transactions in the block
b. Miner of a block
c. All full nodes
d. Sender of transactions in the block
ANSWER: B
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Solidity has data, functions or methods with modifiers, along with getter and setter functions. True or False?
a. True
b. False
ANSWER: True
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The algorithm for consensus in the Bitcoin blockchain is called _____________protocol.
a. Proof of Elapsed Time
b. Proof of Work
c. Proof of Worth
d. Proof of Stake
ANSWER: B
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What is one of the requirements of secure hashing function?
a. It is an ECC function
b. It is a one way function
c. It is log function
d. It is a secret function
ANSWER: B
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Transaction confirmation is independently performed by all miner nodes. True or False?
a. False
b. True
ANSWER: True
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Select the statement with the INCORRECT ending to the sentence "Forks are mechanisms that _________".
a. Reduce the robustness of the blockchain framework
b. Manage issues
c. Implement planned improvements
d. Build credibility
ANSWER: A
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A block in a Blockchain has a header and _______________.
a. Digital Ledger
b. Transactions
c. Inputs
d. Bitcoins
ANSWER: B
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___________ receive, verify, gather and execute transactions.
a. Smart Contracts
b. Ethereum Virtual Machine
c. Miner nodes
d. Light wallets
ANSWER: C
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A blockchain enables peer-to-peer transfer of digital currency without any intermediaries such as bank. True or False?
a. True
b. False
ANSWER: True
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Bootstrapping the new software to the already running processes is known as ____________.
a. Scripting
b. Soft Forks
c. Hashing
d. Hard Forks
ANSWER: B
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An approach for consensus protocol that is hotly debated among developers of blockchain is
a. Proof of Stake
b. Proof of Incentive
c. Round Robin
d. Proof of Age
ANSWER: A
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What type of hash is used when there is a fixed number of items to be hashed, such as the items in a block header, and we are verifying the composite block integrity?
a. Complex hash
b. Either
c. Tree-structured Hash
d. Simple Hash
ANSWER: D
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Block hash allows for the formation of the chain link by embedding the previous block hash in the current block header. True or False?
ANSWER: True
-------------------------------------------
What allows for the execution of code in the Ethereum Blockchain, enhancing the basic value transfer capability of the Bitcoin Blockchain?
a. Ethereum Virtual Machine Proof-of-Work
b. Smart Contracts
c. Solidity
d. Byte-code
ANSWER: B
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An organization wants to develop smart contracts, based on blockchain technology. The organization does not wish to burden employees with maintaining the security of the blockchain. What blockchain technology fits the organization best?
A) A hybrid blockchain
B) A private blockchain
C) A public blockchain
ANSWER: C
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What are UTXOs in a Bitcoin Blockchain?
A) These are transaction output that has been expended
B) These are actual currency that is sent to the receiver of a transaction
C) These form the inputs and outputs for transactions
D) These are rewards for miners
ANSWER: C
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The algorithm for consensus in the Bitcoin blockchain is called _____protocol.
A) Proof of Elapsed Time
B) Proof of Work
C) Proof of Worth
D) Proof of Stake
ANSWER: B
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What is an advantage of a public blockchain?
A) It does not use disinterested third parties to secure blocks, as all participants have a vested interest.
B) It is more resilient against fraud, because it uses federated nodes to combat fraud.
C) It is open to everyone in the world without permission and licensing requirements.
D) Its networks are built by for-profit companies and the working of the network is guaranteed.
ANSWER: C
-------------------------------------------
Which of these facts about a ledger is NOT CORRECT?
A) A ledger is used purely for the reporting of cash.
B) A ledger consists of transactions, often governed by contracts.
C) A ledger is a system of record.
D) A ledger describes the inputs and outputs of a business.
ANSWER: A
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The Monetary Authority of Singapore (MAS) and blockchain company R3 partnered
together. What did they achieve together?
A) The creation of smart contracts and stable coins
B) The facilitation of interbank transmission of messages
C) The first interbank payments without limitations of time zones
D) The launch of wire transfers using cryptography
ANSWER: C
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What is a ScriptPubKey?
A) Unlocking script
B) Input script
C) Output script
D) Locking script
ANSWER: D
-------------------------------------------
_____ receive, verify, gather and execute transactions.
A) Smart Contracts
B) Ethereum Virtual Machine
C) Miner nodes
D) Light wallets
ANSWER: C
-------------------------------------------
The transaction Merkle Tree root value in a Bitcoin block iscalculated using ____.
A) previous block’s hash
B) none
C) hash of transactions
D) number of transactions
ANSWER: C
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How do blockchains function like ledgers?
A) They hold a record of all transactions that have ever occurred on a network.
B) They hold vast amounts of transaction data as a centralized database.
C) They periodically update all balances of each wallet to the blockchain.
ANSWER: A
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What factors can help ensure a successful FIRST BlockChain use case project?
A) A limited scope
B) A smaller business network
C) A scalable project that can grow participants and scenarios
D) All of these
ANSWER: D
-------------------------------------------
What is digital fiat currency?
A) A digital form of currency, that represents a country’s financial reserves
B) An e-currency, that creates a transparent and borderless debt market
C) An online system, that enables making transactions without a bank account
ANSWER: A
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Which of the following is correct about Ethereum Networks?
A) Ethereum has two types of networks: Live network and Test network
B) Ethereum has only one type of network called live network which is also known as main network
C) Ethereum has three types of network: Live Network, Test Network, and Private Network.
D) Ethereum has two types of networks: Live network and Private network
ANSWER: C
-------------------------------------------
What type of hashing algorithm does Bitcoin blockchain useto determine the has
of a block?
A) SHA-512
B) MD5
C) SHA-256
D) SHA-1
ANSWER: C
-------------------------------------------
What qualifies as a currency. In economics, the following criteria must be
satisfied:A–Medium of exchangeB–Unit of accountC–Store of valueD-All of above
A) A
B) B
C) C
D) D
ANSWER: D
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A bearer instrument used to transfer value between two parties over a blockchain
network. What is this instrument?
A) A DApp
B) A Hash
C) A Node
D) A Token
ANSWER: D
-------------------------------------------
How does blockchain technology benefit the insurance industry?
A) By avoiding compliance requirements of national authorities, which reduces overhead
B) By ensuring accuracy of data and automating micro insurances, which reduces costs
C) By introducing flexible premiums to be paid by customers, which increases profits
D) By setting up a digital mode of payment, which simplifies claims settlement
ANSWER: B
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Hyperledger allows which of the following to be plugged?
A) Consensus mechanism
B) Identity mechanism
C) Both the options
D) None of the options
ANSWER: C
-------------------------------------------
In Ethereum, which algorithm is applied to the private key in order to get aunique
public key.
A) RSA
B) Keccak
C) SHA 256
D) ECC
ANSWER: D
-------------------------------------------
What is an example of the use of cryptography in a blockchain?
A) Accessing private or hybrid blockchains by using a private key
B) Creating cryptocurrency as a reward for mining nodes
C) Keeping blockchains secure from 51% attacks by corrupt nodes
D) Securing transfers of cryptocurrency between recipients
ANSWER: D
-------------------------------------------
How does blockchain technology help to protect intellectual property rights (IP)?
A) It allows a user to include IP transactions in smart contracts.
B) It allows a user to record an event and establish the timeline.
C) It allows a user to record the creation of software packages.
D) It allows a user to send a transaction and receive IP ownership.
ANSWER: B
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WHAT IS THE NAME OF THE FIRST ACADEMIC PAPER THAT DESCRIBES
BITCOIN COMMONLY REFERRED TO AS?
A) The origins of money
B) The Bitcoin Whitepaper
C) The great unrevealing
D) None of the above
ANSWER: B
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What are miners who solved the puzzle but didn't win the block creationcalled?
A) Sisters
B) Cousins
C) Brothers
D) Ommers
ANSWER: D
-------------------------------------------
Which of the following methods can be used to obtain the original messagefrom its
generated hash message using SHA-256?
A) Hashing the reverse of generated hash
B) Hashing the generated hash again, twice
C) Hashing the generated hash again
D) Original message cannot be retrieved
ANSWER: D
-------------------------------------------
How do blockchains use private and public-key cryptography?
A) Asymmetric encryption allows a sender to transfer cryptocurrency to a public key. The recipient can then access these funds with their private key and hold it in their wallet.
B) In public-key cryptography, one key is used to encrypt and decrypt transaction. The sender uses this key to send cryptocurrency and the recipient’s wallet holds it after decryption.
C) Symmetric encryption allows a sender to transfer cryptocurrency to another user. The recipient can then access their funds when the sender grants access to their private key.
D) The algorithm in the blockchain encrypts and stores private and public keys to all user's wallets. Cryptocurrency then accesses their funds through their twentyword passphrase key.
ANSWER: A
-------------------------------------------
What is an example of how a government is actively promoting the use of blockchain?
A) China has created a regulatory sandbox that allows them to closely monitor the experiments in blockchain mining and create their own cryptocurrency.
B) Estonia offers e-Residency software, which is available to anyone in the world interested in operating a business online and from within the European Union.
C) Singapore’s Monetary Authority (MAS) is creating central bank digital money for payments between banks using distributed ledger technology (DLT).
ANSWER: C
-------------------------------------------
First step of Blockchain project implementation is?
A) Requirement identification
B) Feasible study on the security
C) Controlling and monitoring the project
D) Screen idea consideration
ANSWER: A
-------------------------------------------
_________ is paid fees for the creation of a block.
A) Receiver of transactions in the block
B) Miner of a block
C) All full nodes
D) Sender of transactions in the block
ANSWER: B
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How do hybrid blockchain networks combat 51% attacks?
A) Through a central controller ensuring the security of each node in the network
B) Through a Proof of Work (PoW) algorithm, which allows miners to secure the network
C) Through incentivization, where miners receive currency for securing the network
D) Through Merkle tree roots, that allow the network to restore itself to its last valid
block
ANSWER: D
-------------------------------------------
Why is blockchain described as the technology that adds a layer of trust to the internet?
A) It allows individuals and groups to work together without having to trust each other or establish authority.
B) It creates a dedicated virtual private network (VPN) tunnel between two or more parties to carry out online fund transfers.
C) It provides mechanism for the government to create their own digital fiat currency as a replacement of physical currency.
D) It provides multifactor authentication to create and update records of cryptocurrency transactions securely.
ANSWER: A
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WHAT DOES A LEDGER IN BLOCKCHAIN DOES?
A) Mapping between owner and object
B) Identification of objects owned
C) Identification of owners
D) None of these
ANSWER: A
-------------------------------------------
In Ethereum, hashing functions are used for which of the following?1. Generating state hash.2. Generating account addresses.3. Decrypting senders message.4. Generating block header hash.
A) 1, 3, 4
B) 1, 2, 4
C) 2, 3, 4
D) 1, 2, 3
ANSWER: B
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What is the task of miners in a blockchain network?
A) Miners act as a single third party to aggregate records and provide trust in the network by the miners’ authority.
B) Miners are computers that allow access to the blockchain, ensuring the number of corrupt nodes will stay low.
C) Miners are nodes that compete for a reward by calculating the correct nonce to make a transaction possible.
D) Miners determine the consensus rules that should be followed and interfere when these rules are broken.
ANSWER: C
-------------------------------------------
WHICH SITE RUN BY ROSS ULBRICHT WAS CLOSED BY THE FBI FOR
LETTING PEOPLE BUY DRUGS WITH BITCOIN?
A) Silk Road
B) Lace Place
C) Silk Street
D) Dark Alley
ANSWER: A
-------------------------------------------
WHERE IS THE BITCOIN CENTRAL SERVER LOCATED?
A) Washington DC
B) Undisclosed Location
C) London
D) None of these
ANSWER: D
-------------------------------------------
What is the purpose of using a digital signature?
A) None of the above.
B) It supports the integrity of messages
C) It supports both user authentication and integrity of messages
D) It supports user authentication
ANSWER: C
-------------------------------------------
Which description fits only the Proof of Work (PoW) consensus algorithm?
A) A collaborative consensus algorithm, where approved accounts do the validation.
B) A collaborative consensus algorithm that is facilitated by farmers, who offer leftover memory of their computer to make transactions possible.
C) A consensus algorithm, where the validation is done for the entire transaction flow, including not only the correctness, but also the sequence of transactions.
D) An intensive and expensive, competitive algorithm where each mining node on the blockchain is competing to secure blocks.
ANSWER: D
-------------------------------------------
WHICH OF THESE US STATES INTRODUCED THE BITLICENSE
REGULATION FOR CRYPTOCURRENCY COMPANIES?
A) New York
B) California
C) Texas
D) Washington
ANSWER: A
-------------------------------------------
WHICH OF THE FOLLOWING IS IMPORTANT FOR BLOCKCHAIN
A) Database Security
B) Auditing
C) Planning
D) None of these
ANSWER: C
-------------------------------------------
What is one of the requirements of secure hashing function?
A) It is an ECC function
B) It is a one way function
C) It is log function
D) It is a secret function
ANSWER: B
-------------------------------------------
Digital signing of a transaction/document involves, hashing the content ofthe document and then ____.
A) encrypting it with nonce
B) rehashing it
C) encrypting it with public key
D) encrypting it with private key
ANSWER: D
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A competitive consensus algorithm that was developed because blockchains had difficulty meeting the transaction speed demands. Which consensus algorithm is this?
A) Delegated Proof of Stake (DPoS)
B) Proof of Burn (PoB)
C) Proof of Stake (PoS)
D) Proof of Work (PoW)
ANSWER: C
-------------------------------------------
WHAT IS THE NAME OF THE FAMOUS BITCOIN EXCHANGE FROM JAPAN THAT COLLAPSED IN 2014?
A) Blockchain.info
B) Tradehill
C) Mt. Gox
D) Bitstamp
ANSWER: C
-------------------------------------------
WHAT IS THE INITIAL APPLICATION FOR WHICH BLOCKCHAIN WAS DESIGNED?
A) Peer-to-peer finance application
B) Research Project
C) Open source finance software to connect Banks
D) None of these
ANSWER: D
-------------------------------------------
What type of hash is used when there is a fixed number of items to behashed, such as the items in a block header, and we are verifying thecomposite block integrity?
A) Complex hash
B) Either
C) Tree-structured Hash
D) Simple Hash
ANSWER: D
-------------------------------------------
In Ethereum, the block hash is the hash of all the elements in the_________ .
A) Transaction hash tree
B) Block header
C) State tree
D) Receipt tree
ANSWER: B
-------------------------------------------
Which consensus algorithm is the least energy efficient?
A) Delegated Proof of Stake (DPoS)
B) Proof of Authority (PoA)
C) Proof of Space (PoSpace)
D) Proof of Work (PoW)
ANSWER: D
-------------------------------------------
WHAT IS UTXO?
A) United Transaction Office
B) United Texan Xerox Organization
C) Unspent Transaction Output
D) Union of Texas Operations
ANSWER: C
-------------------------------------------
What type of hash function is used, when there is variable number of itemsto be hashed, such as the many state changes in a block?
A) Simple Hash
B) Tree-structured Hash
C) Either
D) Complex hash
ANSWER: B
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Merkle tree hash is used for computing _________ hash.
A) state root
B) transaction root
C) receipt root
D) all of the above
ANSWER: D
-------------------------------------------
An attacker tries to corrupt the transaction history of a blockchain to be able to spend
a token or a cryptocurrency twice. What is the most likely thing this attacker did?
A) The attacker changed the transaction on his node and propagated it in the network.
B) The attacker edited the smart contract and recovered investor’s cryptocurrency.
C) The attacker gained control of more than 51% of the network’s computing power.
D) The attacker hard-forked the network and created a new blockchain network.
ANSWER: C
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What is the best use case for smart contracts?
A) Digitalize and automate legally binding contracts using artificial intelligence (AI)
B) Enforce the execution of contracts in the legal system using cryptocurrencies
C) Ensure automatic payments by predetermined actions or events in insurance contracts
D) Extend the Bitcoin blockchain, the best-known smart contract platform, to the judicial system
ANSWER: C
-------------------------------------------
How are the blocks linked in Blockchain?
A) Backward to the previous block
B) Forward to the next block
C) Both the options
D) None of the options
ANSWER: A
-------------------------------------------
Blockchain was created to support security and trust in a ___________environment
of the cryptocurrency Bitcoin.
A) centralized trusted
B) decentralized trusted
C) centralized trustless
D) decentralized trustless
ANSWER: D
-------------------------------------------
What is a blockchain?
A) A centralized database that holds a subset of all transactions on all nodes.
B) A client-server database existing on a limited number of nodes at the same time.
C) A distributed database with a record of all transactions on the network.
D) A distributed database with a record of all transactions on the network.
ANSWER: D
-------------------------------------------
Which benefits of a Blockchain enabled business network engender TRUST?
A) Efficient, dynamic, cognitive, and reliable
B) Consensus, provenance, immutability, and finality
C) Modern, ideally suitable for digital transformation, and social-enabled
D) Scalable, reliable, secure, and maintainable
ANSWER: B
-------------------------------------------
BITCOIN USES UTXO, ETHEREUM USES:
A) Double spend
B) UTXO
C) Account Balance
D) Ether
ANSWER: C
-------------------------------------------
Blockchain networks are vulnerable to 51% attacks. Which network would
incentivize hackers most to break the network?
A) Bitcoin
B) Fabric
C) Factom
D) Ripple
ANSWER: A
-------------------------------------------
WHEN DID BITCOIN’S CREATOR PUBLISH A WHITEPAPER
INTRODUCING THE DIGITAL CURRENCY?
A) 2007
B) 2008
C) 2009
D) 2010
ANSWER: B
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If a participant node tampers with a block, it results in ____.
A) hash changing
B) mismatch of hash values
C) the local chain of node rendered in an invalid state
D) All of the above
ANSWER: D
-------------------------------------------
Trust in a decentralized blockchain is about ____.
A) validating the transactions and blocks for tamper proofing.
B) securing the chain using specific protocols.
C) executing and confirming the transactions.
D) All of the above
ANSWER: D
-------------------------------------------
Which characteristic of a blockchain network is also its protection?
A) The greater the number of full independent nodes, the harder it is to compromise the data in the blockchain.
B) The lower the number of miners in the blockchain, the higher the incentive is for securing the network.
C) The more centralized the control of the blockchain is, the harder it is to secure the data and avoid fraud.
D) The more complicated the Proof of Work (PoW) algorithm is, the more rewarding it is to secure the network.
ANSWER: A
-------------------------------------------
WHAT IS THE MAXIMUM NUMBER OF BITCOINS THAT CAN BE
CREATED?
A) 16 million
B) 21 million
C) 100 million
D) There is no maximum
ANSWER: B
-------------------------------------------
Which one of the following is correct?
A) A secure blockchain is a single chain in an inconsistent state.
B) There is only one, single criteria measured to perform validation.
C) Neither timestamp nor nonce can be verified.
D) Once a consensus is met, a new block is added to the chain.
ANSWER: D
-------------------------------------------
Which one of the following is correct?
A) A secure blockchain is a single chain in an inconsistent state.
B) There is only one, single criteria measured to perform validation.
C) Neither timestamp nor nonce can be verified.
D) Once a consensus is met, a new block is added to the chain.
ANSWER: D
-------------------------------------------
How can information be secured in a blockchain?
A) By using a closed peer-to-peer (P2P) network, sharing information across platforms
B) By using a distribution of cryptocurrencies over miners through the network
C) By using asymmetric cryptography, consisting of a public and private key
D) By using distributed ledger technology (DLT), which records transactions at the
source
ANSWER: C
-------------------------------------------
WHAT DOES THE BLOCK IN THE BLOCKCHAIN CONSIST OF?
A) Transaction data
B) A Hash point
C) A Timestamp
D) All of the Above
ANSWER: D
-------------------------------------------
WHAT IS THE PROCESS OF CREATING NEW BITCOINS POPULARLY
KNOWN AS?
A) Finding
B) Panning
C) Sourcing
D) Mining
ANSWER: D
-------------------------------------------
An approach for consensus protocol that is hotly debated among developersof
blockchain is
A) Proof of Stake
B) Proof of Incentive
C) Round Robin
D) Proof of Age
ANSWER: A
-------------------------------------------
Blockchain enables self-sovereign identity. How does blockchain do this?
A) It enables centralized third parties to offer easy-to-use and valid identity information.
B) It enables each person to have exclusive control of their money, property and identity.
C) It enables governments to effortlessly issue identities with advanced digital certificates.
D) It enables only internet companies to offer world-class secure personal identity repositories.
ANSWER: B
-------------------------------------------
WHAT IS THE IMPACT OF INFORMATION LEAK FOR AN ORGANIZATION?
A) Loss in profit
B) Loss of trust in costumers
C) Cut down the reputation of the organization
D) All of these
ANSWER: D
-------------------------------------------
WHICH OF THE FOLLOWING IS A NOW-DEFUNCT BITCOIN EXCHANGE?
A) Bit Box
B) Mt Fox
C) Mt Gox
D) Ft Nox
ANSWER: C
-------------------------------------------
What happens if more than one miner solves the consensus puzzle veryclose in time to each other in Ethereum?
A) The new block is added to the main chain and not the runner-up chain
B) Runner-up miners leave the network.
C) Small incentives are given to runner-up blocks
D) Small incentives are given to the runner up blocks and the new blockis added to
the main chain
ANSWER: D
-------------------------------------------
Public blockchains give an incentive to encourage users to mine blocks and secure the network. What incentive is this?
A) Public blockchains allow users to create tokens to sell on secondary markets.
B) Public blockchains do not offer rewards, because they are open source.
C) Public blockchains offer cash rewards for running mining nodes.
D) Public blockchains offer rewards for mining in the form of cryptocurrency.
ANSWER: D
-------------------------------------------
HOW MANY NEW BITCOINS ARE CREATED EVERY DAY?
A) 2200 except leap year
B) 3600
C) 7200
D) 5000
ANSWER: B
-------------------------------------------
Once records are submitted on a blockchain, can they be altered?
A) Yes – the parties can go back in and alter them at any time.
B) Yes – but only within a certain time frame.
C) No – they cannot be altered.
D) It depends upon the records
ANSWER: C
-------------------------------------------
Trust in _________ is the ability to handle natural exceptional situationssuch as a chain split and double spending.
A) smart contracts
B) mining
C) robustness
D) Proof of Work
ANSWER: C
-------------------------------------------
What is a key characteristic of the Hyperledger network?
A) It is a public blockchain network and one of the oldest networks, existing since 2009.
B) It is private, open sourced and can run everyone’s own distributed ledger technology (DLT).
C) It utilizes cryptocurrency as a reward mechanism, which makes the network more secure.
D) It utilizes the Proof of Stake (PoS) consensus algorithm as its main security measure.
ANSWER: B
-------------------------------------------
Bootstrapping the new software to the already running processes is knownas ____.
A) Scripting
B) Soft Forks
C) Hashing
D) Hard Forks
ANSWER: B
-------------------------------------------
Select the statement with the INCORRECT ending to the sentence "Forksare mechanisms that _________"
A) Reduce the robustness of the blockchain framework.
B) Manage issues
C) Implement planned improvements
D) Build credibility
ANSWER: A
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Bitcoin blockchain implemented a soft fork to realize a ____.
A) Split into Bitcoin core and Bitcoin cash
B) P2SH Peer-to-Shell feature
C) P2SH conditional payment script feature
D) P2SH payer gossip feature
ANSWER: C
-------------------------------------------
Which one is true?
A) Bitcoin is decentralized cryptocurrency
B) It does not require a bank or government for transaction.
C) Bitcoin is not a fiat currency
D) All of the above
ANSWER: D
-------------------------------------------
The network timestamps transactions by hashing them into ongoing chain of hash based __________.
A) Method
B) Task
C) Proof of Work
D) Proof of Transaction
ANSWER: C
-------------------------------------------
Proof of work is the __________ used by Bitcoin blockchain and EthereumByzantium Metropolis blockchain.
A) Transaction confirmation
B) Consensus Protocol
C) Incentive function
D) Trust function
ANSWER: B
-------------------------------------------
Digital Signature is a combination of -
A) Message + Private Key
B) Message + Public Key
C) Message + Wallet Address
D) None of these
ANSWER: A
-------------------------------------------
In which scenario is a smart contract the best solution to the problem?
A) A bartender wants to force customers to pay for their drinks by transferring cryptocurrency to his wallet.
B) A chief financial officer wants her smart watch to notify her when her partner enters their front door.
C) An energy company wants to automatically buy power when the price reaches a predetermined rate.
D) An insurance company wants to pay out a farmer whenever the case manager feels it is best to do so.
ANSWER: C
-------------------------------------------
Which of the following characteristics does not let Bitcoin be anonymous?
A) People who use Bitcoin cannot have their transactions traced by anyone
B) Bitcoin addresses are derived from IP addresses
C) All transactions are recorded on a global transparent ledger that can be traced using analytical technologies
D) Bitcoins can be linked to a user’s social security number
ANSWER: C
-------------------------------------------
What/Who are miners in a blockchain?
A) A person who receives money as the receiver of the transaction
B) A person who just initiates a transaction in the blockchain
C) An algorithm that you can use to calculate the next block in ablockchain
D) Computers that validate and process blockchain transactions andsolve the
cryptographic puzzle to add new blocks
ANSWER: D
-------------------------------------------
Transaction 0 in every block in the bitcoin blockchain ____.
A) is for paying the miner fees
B) does not have any input UTXO
C) is called the coinbase transaction
D) All of the above
ANSWER: D
-------------------------------------------
What is the function of a lightweight node within a blockchain network?
A) It stores a complete history of every transaction on the network.
B) It stores purchased cryptocurrency for users of a blockchain network.
C) It verifies transactions by piggybacking on the work of full nodes.
ANSWER: C
-------------------------------------------
What is bitcoin?
A) A technology that underpins Hyperledger Fabric
B) Another name for BlockChain
C) An unregulated censorship resistant shadow currency
D) A private network
ANSWER: C
-------------------------------------------
New transaction is broadcasted to -
A) Destination Node
B) Source Node
C) All Node
D) Blocks
ANSWER: C
-------------------------------------------
What are DApps designed to do?
A) Execute smart contracts with the business logic in the front-end of a standalone application
B) Manage cryptocurrencies only, without any embedded voting system for governance of the blockchain
C) Run applications on a peer-to-peer (P2P) network expanding smart contracts beyond simple value transfer
D) Support applications that run on multiple public cloud providers avoiding any vendor lock-in and fraud
ANSWER: C
-------------------------------------------
Which of the following is not a type of Ethereum tools?
A) Geth
B) IPFS
C) Swarm
D) Web3.js
ANSWER: D
-------------------------------------------
Validation, Verification, Immutable Recording, and _____ lead to Trustand Security.
A) Coins
B) Algorithms
C) Tokens
D) Consensus
ANSWER: D
-------------------------------------------
What is not a classification for a node?
A) Full node
B) Lightweight node
C) Merkle node
D) Miner node
ANSWER: C
-------------------------------------------
What is the core requirement(s) for a business BlockChain?
A) Shared ledger, smart contract, privacy, and trust
B) Optimized cryptographic mining
C) A new cryptocurrency
D) Technical services, business services, and solution
ANSWER: D
-------------------------------------------
What is the role of a DAO (decentralized autonomous organization)?
A) Address the principal-agent dilemma with collaboration and acceptance of actions within agreed rules
B) Embed regulated online smart contracts with the current judicial system, using public blockchains
C) Offer complex online smart contracts without any link to tangible and intangible offline assets
D) Provide a private blockchain contract platform on which users can run their online applications
ANSWER: A
-------------------------------------------
Which of these Blockchain network participants performs B2B transactions?
A) Blockchain Developer
B) Regulator
C) Certificate Authority
D) Blockchain User
ANSWER: D
-------------------------------------------
Which of these fields is present in a Bitcoin block summary?
A) Gas Limit
B) Difficulty
C) Gas Used
D) Private Key of the Sender
ANSWER: B
-------------------------------------------
A bearer instrument used to transfer value between two parties over a blockchain
network. What is this instrument?
A) DApp
B) Hash
C) Node
D) Token
ANSWER: D
-------------------------------------------
The primary benefit of immutability is …
A) Scalability
B) Tamper-proof
C) Improved security
D) Increased efficiency
ANSWER: B
-------------------------------------------
How can blockchain technology best help securing identity data?
A) By eliminating third parties through providing secured-data storage at a user’s server
B) By encoding all the health data and save it on a private and permissionless blockchain
C) By protecting data that has been submitted on the internet using a cryptographic algorithm
D) By providing information personal data without disclosing the actual data that proves it
ANSWER: D
-------------------------------------------
Which of the following is not a property of Permissioned Blockchain?
A) Proof of Stake
B) Low transaction cost
C) Same level access to all participants
D) Trusted environment
ANSWER: C
-------------------------------------------
Did Bitcoin enable a centralized or a decentralized system for exchange ofvalue?
A) Centralized
B) Decentralized
C) Both
D) None of the Above
ANSWER: B
-------------------------------------------
What is the differentiating factor between the Ethereum Blockchain and theBitcoin
blockchain?
A) Smart contracts
B) Currency Exchange
C) Distributed ledger
D) Wallets
ANSWER: A
-------------------------------------------
What is a key characteristic of a public blockchain?
A) Allowing a user to elect nodes to process transactions
B) Allowing anyone to participate in the blockchain network
C) Allowing control over who can participate and at what level
D) Allowing only trusted parties to operate their blockchain
ANSWER: B
-------------------------------------------
A smart contract is …
A) Business rules implied by the contract embedded in Block Chain
B) A cognitive contract
C) A legal contract is written in constrained English
D) None of these
ANSWER: A
-------------------------------------------
What is the value of using blockchain networks with Internet of Things (IoT)?
A) Allowing blockchain users to follow self-driving cars and access these cars
B) Avoiding a spoofing attack using the secured identity that is stored on a blockchain
C) Enabling software that programs itself to solve problems without human intervention
D) Solving expensive and complex calculations using Hyperledger Fabric mining
ANSWER: B
-------------------------------------------
Which of the following is a program that initiates a transaction?
A) Ordering Service
B) Fabric Peer
C) Client Application
D) Chaincode
ANSWER: D
-------------------------------------------
Miners are computers that execute ____.
A) operations defined by users
B) operations defined by the blockchain protocol
C) operations defined by transactions
D) None
ANSWER: B
-------------------------------------------
Calculate the amount of gas points required to execute an operation thatinvolves 2 steps and 1 load from memory. Use the following image.
A) 1
B) 22
C) 23
D) 42
ANSWER: B
-------------------------------------------
What is an example of the use of cryptography in a blockchain?
A) Accessing private or hybrid blockchains by using a private key
B) Creating cryptocurrency as a reward for mining nodes
C) Keeping blockchains secure from 51% attacks by corrupt nodes
D) Securing transfers of cryptocurrency between recipients
ANSWER: D
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In a business BlockChain, transactions …
A) Cannot be modified
B) Are added to the ledger with appropriate confidentiality
C) Are endorsed by a subset of business network participants
D) All of these
ANSWER: D
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Blockchain technology has made decentralized marketplaces possible. What is a benefit of a decentralized marketplace?
A) It is based on open-source technology, so it can be used without any investment
B) It is not under a paid license to operate and therefore it is managed better
C) It is relatively cheap due to the use of cryptocurrency and is very accessible
D) It is tamper-proof, resilient to being shut down and trustworthy due to smart contracts
ANSWER: D
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Which of the following is a file exported after packaging the Business Network Definition to be deployed somewhere?
A) Model File (.cto)
B) Business Network Archive (.bna)
C) Script File (.js)
D) Query Definition (.qry)
ANSWER: B
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External Owned Accounts (EOA) are controlled by ____.
A) Public Key
B) Hash of the first transaction by that account
C) Private Key
D) Public Key and Private Key
ANSWER: C
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Which of the following is true about an externally owned account (EOA) inEthereum Homestead?
A) EOAs execute code when triggered by a transaction.
B) EOAs have associated code with them.
C) EOAs can send transactions (ether transfer or invoke a contract code)
D) None of these
ANSWER: C
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How do blockchains use private and public-key cryptography?
A) Asymmetric encryption allows a sender to transfer cryptocurrency to a public key. The recipient can then access these funds with their private key and hold it in their wallet.
B) In public-key cryptography, one key is used to encrypt and decrypt transaction. The sender uses this key to send cryptocurrency and the recipient’s wallet holds it after decryption.
C) Symmetric encryption allows a sender to transfer cryptocurrency to another user. The recipient can then access their funds when the sender grants access to their private key.
D) The algorithm in the blockchain encrypts and stores private and public keys to all user's wallets. Cryptocurrency then accesses their funds through their twentyword passphrase key.
ANSWER: A
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What is the appropriate use of business BlockChain?
A) Modern, cognitive, and transformational fabric for the 21st century and beyond
B) A more efficient transaction processing system across a business network
C) To make low value, high volume micropayments systems more efficient
D) None of these
ANSWER: B
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How does blockchain improve supply chains?
A) By automatically creating trade agreements between two parties
B) By creating safe centralized marketplaces to trade goods on
C) By stabilizing the national currencies of the countries involved
D) By transferring tokenized ownership through a software system
ANSWER: D
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Which of the following is an example of asymmetric encryption?
A) Tripple DES
B) Blowfish
C) RSA
D) AES
ANSWER: C
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____ hosts the software needed for transaction initiation, validation,mining, block creation, and smart contract execution.
A) EVM
B) Ethereum full node
C) External Account
D) Smart Contract
ANSWER: B
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What is the correct sequence involved in a block creation:1. Transactions validated2. Transactions Bundled & broadcasted3. Transaction initiated4. Block added to the local chain and propagated to the network.5. Proof of work consensus problem solved
A) 3, 2, 1, 4, 5
B) 3, 1, 2, 5, 4
C) 1, 2, 3, 4, 5
D) 5, 3, 1, 2, 4
ANSWER: B
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How do hybrid blockchain networks combat 51% attacks?
A) Through a central controller ensuring the security of each node in the network
B) Through a Proof of Work (PoW) algorithm, which allows miners to secure the network
C) Through incentivization, where miners receive currency for securing the network
D) Through Merkle tree roots, that allow the network to restore itself to its last valid block
ANSWER: D
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What makes a good Block Chain use case?
A) An identifiable business network
B) A business problem to be solved
C) The need for trust
D) All of these
ANSWER: D
-------------------------------------------
WHAT IS A NODE?
A) A type of cryptocurrency
B) A Blockchain
C) A computer on a Blockchain network
D) An exchange
ANSWER: C
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WHAT INCENTIVIZES THE MINERS TO GIVE CORRECT VALIDATION OF TRANSACTIONS?
A) A nonce
B) A block reward
C) Thumbs up from the community
D) More memory
ANSWER: B
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WHAT IS THE PURPOSE OF A NONCE?
A) Follows nouns
B) A hash function
C) Prevents double spending
D) Sends information to the blockchain network
ANSWER: C
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WHAT IS THE NAME OF THE RESEARCH PAPER THAT BROUGHT BITCOIN TO THE WORLD?
A) Black Paper
B) White Paper
C) Yellow Paper
D) Green Paper
ANSWER: B
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BITCOIN USES UTXO, ETHEREUM USES:
A) Double spend
B) UTXO
C) Account Balance
D) Ether
ANSWER: C
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WHAT ARE SIDECHAINS?
A) Another term for a hash function
B) Smart Contracts that have forked off the main Blockchain
C) A parallel network running adjacent to the main blockchain network for additional security
D) Any mechanism that allows tokens from one blockchain to be securely used within a completely separate Blockchain
ANSWER: D
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WHAT IS A LITECLIENT?
A) Allows you to interact with the blockchain without downloading the whole blockchain
B) A type of cryptocurrency
C) A platform to develop dApps
D) A server
ANSWER: A
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WHEN A RECORD IS ON A BLOCKCHAIN, WHO CAN ACCESS IT?
A) Multiple people simultaneously.
B) One person at a time.
C) Only the people involved in the transaction.
ANSWER: A
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ONCE RECORDS ARE SUBMITTED ON A BLOCKCHAIN, CAN THEY BE ALTERED?
A) Yes – the parties can go back in and alter them at any time.
B) Yes – but only within a certain time frame.
C) No – they cannot be altered.
ANSWER: C
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WHEN DID BITCOIN’S CREATOR PUBLISH A WHITEPAPER INTRODUCING THE DIGITAL CURRENCY?
A) 2007
B) 2008
C) 2009
D) 2010
ANSWER: B
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WHAT IS THE MAXIMUM NUMBER OF BITCOINS THAT CAN BE CREATED?
A) 16 million
B) 21 million
C) 100 million
D) 116 million
ANSWER: B
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WHICH OF THE FOLLOWING IS A NOW-DEFUNCT BITCOIN EXCHANGE?
A) Bit Box
B) Mt Fox
C) Mt Gox
D) Ft Nox
ANSWER: C
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WHERE DO YOU STORE YOUR CRYPTOCURRENCY?
A) Bank account
B) Floppy Disk
C) Wallet
D) In your pocket
ANSWER: C
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WHAT IS A GENESIS BLOCK?
A) The first block of a Blockchain
B) A famous block that hardcoded a hash of the Book of Genesis onto the blockchain
C) The first block after each block halving
D) The 2nd transaction of a Blockchain
ANSWER: A
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WHAT IS THE PROCESS OF CREATING NEW BITCOINS POPULARLY KNOWN AS?
A) Finding
B) Panning
C) Sourcing
D) Mining
ANSWER: D
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WHAT IS THE NAME OF THE FAMOUS BITCOIN EXCHANGE FROM JAPAN THAT COLLAPSED IN 2014?
A) Blockchain.info
B) Tradehill
C) Mt. Gox
D) Bitstamp
ANSWER: C
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WHAT DOES THE BLOCK IN THE BLOCKCHAIN CONSIST OF?
A) Transaction data
B) A Hash point
C) A Timestamp
D) All of these
ANSWER: D
-------------------------------------------
WHAT IS NOT A LEDGER TYPE CONSIDERED BY USERS IN BLOCKCHAIN?
A) Distributed Ledger
B) Decentralized Ledger
C) Both a and b
D) None of these
ANSWER: D
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WHAT IS THE IMPACT OF AN INFORMATION LEAK FOR AN ORGANIZATION?
A) Loss in profit
B) Loss of trust in costumers
C) Cut down the reputation of the organization
D) All of these
ANSWER: D
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HOW OFTEN DOES THE BITCOIN LEDGER RECONCILE?
A) Every day
B) Every 3 months
C) Every 3 Minutes
D) Every 10 Minutes
ANSWER: D
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WHAT IS A MINER?
A) A type of blockchain
B) An algorithm that predicts the next part of the chain
C) A person doing calculations to verify a transaction
D) Computers that validate and process blockchain transactions
ANSWER: D
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WHAT IS A PRIVATE KEY?
A) A key on your key chain
B) A key given to the public
C) A key NOT to be given to the public
D) A key that opens a secret door
ANSWER: C
-------------------------------------------
WHAT ARE THE DIFFERENT TYPES OF TOKENS?
A) Platform
B) Privacy
C) Currency
D) All of the above
ANSWER: D
-------------------------------------------
WHAT POWERS THE ETHEREUM VIRTUAL MACHINE?
A) Gas
B) Ether
C) Bitcoin
D) Block Rewards
ANSWER: A
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WHERE CAN YOU BUY CRYPTOCURRENCY?
A) A private transaction
B) An exchange
C) A Bitcoin ATM
D) All of the above
ANSWER: D
-------------------------------------------
ASYMMETRIC ENCRYPTION USES:
A) Public keys only
B) Private keys only
C) Public and Private keys
D) Proof of Stake
ANSWER: C
-------------------------------------------
WHICH IS NOT A PART OF ASYMMETRIC ENCRYPTION?
A) Mining
B) Public key
C) Passphrase
D) Private Key
ANSWER: A
-------------------------------------------
WHAT IS PROOF OF STAKE?
A) A certificate needed to use the blockchain
B) A password needed to access an exchange
C) How private keys are made
D) A transaction and block verification protocol
ANSWER: D
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WHAT IS A BLOCKCHAIN?
A) A distributed ledger on a peer to peer network
B) A type of cryptocurrency
C) An exchange
D) A centralized ledger
ANSWER: A
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WHAT IS A HASH FUNCTION?
A) A fork
B) UTXO
C) Takes an input of any length and returns a fixed-length string of numbers and letters
D) Gas
ANSWER: C
-------------------------------------------
WHAT IS A DAPP?
A) A type of Cryptocurrency
B) A condiment
C) A type of blockchain
D) A decentralized application
ANSWER: D
-------------------------------------------
WHAT DOES IPFS STAND FOR?
A) Interplanetary File System
B) Inter Filing System
C) Internet Platform for Storage
D) Internet Play Store
ANSWER: A
-------------------------------------------
WHAT IS THE TERM FOR WHEN A BLOCKCHAIN SPLITS?
A) A fork
B) A merger
C) A sidechain
D) A division
ANSWER: A
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WHAT IS A DASH MASTERNODE?
A) Two nodes sharing resources
B) A single node that runs the whole network
C) A node that provides additional supervisory network services
D) Master of all Dash nodes
ANSWER: C
-------------------------------------------
WHAT CHARACTERISTIC MAKES BLOCKCHAIN TAMPER-PROOF?
A) VPN
B) Immutability
C) Cryptocurrency
D) Servers
ANSWER: B
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Generate the public key value for the following private key: 560382812
A)04c75670c43cf22391967dce8f9e58dc345e9773e5c09d8c5fb9c1f90a8b032a97a92716955ceda17ad750b9dfd7a988f9c038abf599cbc7581c81c17b9e0214f8
B)04ee4aa2c846b4ee649287e5f8344a3fcb3c638f42dbb06e892eb4df425876d27d5d0c0f8bb1303f08cff510bf0bfd0fb96c841d14980e3f70804359b61a9f27f0
C)04d05923eb01beb5d3d6a1df425eb75a199a50764fa48dd4e7fa355b7b93938d5e8897ce60e3b64a98e3dcf385fd814a4b98885d7b6348ce8d259c0e0ea2badc4a
D)040dbe82ef7395511d3bfe0dbf8cbc78a7c986e3f796557b976301e589286b7a69076832e2a36af5fc628f0450a036729cc76e911b999430263d60d31af8b07861
ANSWER: C
_____________________________________
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