A security analyst is assessing the risk of a 51% attack on a small PoW blockchain. The network's hash rate is relatively low. Which combination of factors would most increase the feasibility of a 51% attack?

High transaction fees and a large number of active miners.

A large market cap and high liquidity of the coin.

Frequent difficulty adjustments and a short block time.

Low network hash rate and the ability to rent significant hash power from a cloud provider.

A miner is considering joining a mining pool that uses a PPLNS (Pay Per Last N Shares) reward system. They have intermittent mining availability due to power outages. What is the main drawback of PPLNS for this miner?

They will be required to run a full node to participate.

They will not receive any rewards until they have mined for a full day.

They will be charged higher fees than other reward systems.

They may receive reduced rewards for blocks found during periods when they were not actively mining.

A miner is preparing to mine a block. They have selected transactions from the mempool. What is the next step in the mining process?

Wait for the next difficulty adjustment before proceeding.

Verify the transactions by re-executing them against the current UTXO set.

Build a candidate block header and begin hashing with a varying nonce.

Broadcast the block to the network immediately to claim the reward.

In Delegated Proof of Stake (DPoS), how are block producers (witnesses) selected?

By the order in which they join the network

By solving a cryptographic puzzle faster than others

By coin holders voting for a fixed number of delegates

By a lottery based on the amount of stake each validator holds

Which of the following is a potential consequence of a successful 51% attack?

Creating new coins out of thin air

Double-spending of transactions

Stealing private keys from users

Changing the block reward amount

EC-CouncilBlockchain Developer Certification

Domain 4Objective 2

Mining Techniques BDC Practice Questions (Page 2)

Part of the Cryptomining, Tokenization, and Digital Assets domain, which makes up ~10% of our current practice bank.

48questions here

10free pages

11concepts

Questions 6–10

6expert · hard
A security analyst is assessing the risk of a 51% attack on a small PoW blockchain. The network's hash rate is relatively low. Which combination of factors would most increase the feasibility of a 51% attack?
Select an answer first
7expert · hard
A miner is considering joining a mining pool that uses a PPLNS (Pay Per Last N Shares) reward system. They have intermittent mining availability due to power outages. What is the main drawback of PPLNS for this miner?
Select an answer first
8application · medium
A miner is preparing to mine a block. They have selected transactions from the mempool. What is the next step in the mining process?
Select an answer first
9foundation · easy
In Delegated Proof of Stake (DPoS), how are block producers (witnesses) selected?
Select an answer first
10foundation · easy
Which of the following is a potential consequence of a successful 51% attack?
Select an answer first

Finished these 5 questions?

Review the revealed explanations, or continue through the curriculum.

Next 5 questions →Back to BDC

Free Basic Practice is a study aid with revealable answers — not a scored exam. Examers.io is independent and not affiliated with or endorsed by EC-Council. “BDC” is a trademark of its owner, used for identification only.