Test Flashcards
11 cards from real Blockchain Technology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 11 Test flashcards as text
What are the applications of Smart Contract
Answer: All of the above
Smart contracts have diverse applications across numerous sectors due to their ability to automate and enforce agreements without intermediaries. They can streamline logistics and supply chain management in transportation, automate claims processing in insurance, and facilitate digital rights management for protecting copyrighted content. Their versatility makes them valuable in many industries.
What is the meaning of EVM
Answer: Ethereum Virtual Machine
EVM stands for Ethereum Virtual Machine. It is the core runtime environment for executing smart contracts on the Ethereum blockchain. The EVM is a Turing-complete virtual machine that ensures deterministic and secure execution of decentralized applications, allowing developers to build complex logic that operates reliably across the network.
The scenario where one digital token is spent multiple times because the token generally consists of a digital file that can easily be cloned is known as
Answer: Double-spending
Double-spending is a critical problem in digital currencies where a single digital token is illicitly spent more than once. Unlike physical cash, digital files can be easily copied, making this a significant challenge. Blockchain technology was specifically designed with distributed ledgers and consensus mechanisms to prevent double-spending, ensuring that each transaction is unique and irreversible once confirmed.
It is the situation where malicious miners/ attackers are present in the majority of a blockchain network
Answer: 51% attack
A 51% attack occurs when a single entity or group gains control of more than 50% of a blockchain network's mining or staking power. With this majority, the attacker can manipulate the network by preventing new transactions from being confirmed, reversing confirmed transactions (double-spending), and effectively reorganizing the blockchain's history, thereby undermining its security and integrity.
_______ transactions are the transactions occurring on the cryptocurrency network that moves value outside the network
Answer: Off-chain
Off-chain transactions are those that occur outside the main blockchain network, often processed using payment channels or sidechains. These transactions typically offer faster processing times and lower fees compared to on-chain transactions. They are eventually settled or recorded on the main chain, helping to improve the scalability and efficiency of blockchain networks by reducing congestion on the primary ledger.
A Coinbase transaction is the _______ in a block. It is a unique type of bitcoin transaction that can be created by a miner.
Answer: First Transaction
A Coinbase transaction is a unique and special type of transaction that is always the first transaction included in any new block mined on a blockchain. It does not have an input from a previous transaction; instead, it creates new coins as a reward for the miner who successfully found the block, along with any collected transaction fees.
Kind of attack which miner mines a block with his transaction and does not release it in the system
Answer: Finney Attack
A Finney Attack is a specific double-spending attack where a miner creates a transaction to themselves, mines a block containing it, and then quickly sends the same coins to a merchant before releasing their privately mined block. The merchant accepts the payment, but the miner then releases their block, effectively reversing the merchant's transaction. This attack requires the attacker to be a miner and have a pre-mined block.
The attacker may send the same coin to different vendors in rapid succession, probably by using two machines
Answer: Race Attack
A Race Attack involves an attacker sending the same coins to two different recipients almost simultaneously, typically by broadcasting two separate transactions to the network. The goal is to exploit the delay in network propagation, hoping that both transactions are accepted by different nodes before the network can fully propagate and confirm only one. This can lead to one of the recipients not receiving the funds they expected.
The attacker mines a private blockchain where he double-spends the coins.
Answer: The 51% Attack
The 51% Attack is a scenario where an attacker gains control of the majority of a blockchain network's hashing power. This allows them to mine a private blockchain faster than the legitimate public chain, enabling them to double-spend coins by confirming transactions on their private chain and then releasing it to overwrite the public chain's history, effectively reversing previous transactions.
Which of the following is a type of Blockchain?
Answer: Private Blockchain
Blockchains are generally categorized into Public, Private, and Consortium (or Hybrid) types based on their access and permission structures. A Private Blockchain is a specific type where write permissions are centralized to one organization, and participation often requires explicit invitation. Ethereum, while a blockchain platform, is primarily known for its public blockchain network.
Which of the following is an important elements in Blockchain ecosystem?
Answer: All of the above
A robust blockchain ecosystem relies on the synergistic operation of several key elements. Nodes are the computers that maintain and validate the network, the shared ledger is the immutable record of all transactions, and consensus algorithms ensure agreement among participants on the ledger's state. All these components are fundamental for the functionality, security, and integrity of a blockchain network.