CCE Smart Contracts and Ethereum 3

Question 1

What is a blockchain oracle?

Accepted Answer

A service that provides smart contracts with real-world external data they cannot access directly

Answer

A blockchain oracle is a service that bridges the gap between the blockchain and the outside world, supplying smart contracts with external data such as price feeds, weather, or event outcomes.

Question 2

What is a DAO (Decentralized Autonomous Organization)?

Accepted Answer

An organization governed by smart contracts and token holder voting rather than traditional management

Answer

A DAO is an organization whose governance rules are encoded in smart contracts, where token holders vote on proposals and decisions are executed automatically, removing the need for centralized management.

Question 3

What does Ethereum's DELEGATECALL opcode do?

Accepted Answer

Executes another contract's code but within the storage context of the calling contract

Answer

DELEGATECALL runs the called contract's code using the calling contract's own storage, msg.sender, and msg.value, which is the foundation of upgradeable proxy contract patterns.

Question 4

What is the primary purpose of the proxy contract pattern in smart contract development?

Accepted Answer

To enable smart contract logic to be upgraded while preserving the same contract address

Answer

The proxy pattern separates storage from logic, allowing developers to deploy a new implementation contract and point the proxy to it, effectively upgrading contract behavior while users keep interacting with the same address.

Question 5

What is 'front-running' in the context of Ethereum smart contracts?

Accepted Answer

When a miner or bot detects a pending profitable transaction and inserts their own transaction ahead of it with a higher gas fee

Answer

Front-running occurs when a party monitors the public mempool, spots a profitable pending transaction, and submits their own transaction with a higher gas price to be executed first and capture the profit.

(CCE) Certified Cryptocurrency Expert Practice Test

(CCE) Certified Cryptocurrency Expert Practice Test

CCE Smart Contracts and Ethereum 3