Smart Contract Fundamentals Flashcards
7 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 7 Smart Contract Fundamentals flashcards as text
What is a 'time lock' contract, and why do DeFi protocols use them?
Answer: A contract that enforces a mandatory delay between proposing and executing governance changes
Time locks impose a waiting period (e.g., 48 hours) on admin actions, giving users time to react and exit before potentially harmful changes take effect.
What is the purpose of the 'modifier' keyword in Solidity?
Answer: It defines reusable pre/post condition checks that wrap function execution
Modifiers inject guard logic (like onlyOwner or nonReentrant) around a function, making access control and validation reusable across many functions.
In the context of Ethereum smart contracts, what is 'MEV' (Maximal Extractable Value)?
Answer: Profit extracted by reordering, inserting, or censoring transactions within a block
MEV refers to value that block producers (miners/validators) or searchers can capture by controlling transaction ordering, enabling strategies like arbitrage and liquidations.
What does the 'immutable' keyword do in Solidity?
Answer: Allows a variable to be set once at construction and then permanently read-only
'immutable' variables are written once in the constructor and then inlined into the bytecode, making reads cheaper than storage reads while still being configurable per deployment.
What is a 'Soulbound Token' (SBT) as proposed by Vitalik Buterin?
Answer: A non-transferable NFT permanently linked to a specific wallet as a form of digital identity or credential
SBTs are non-transferable tokens that represent credentials, achievements, or memberships tied to an individual's on-chain identity, similar to a digital resume.
What does 'ABI encoding' accomplish when you call a smart contract function externally?
Answer: It serializes the function selector and arguments into bytes the EVM can parse
ABI encoding converts a function name and its typed arguments into a standardized byte array: the first 4 bytes are the function selector, followed by encoded parameters.
Which design pattern is commonly used to deploy many identical smart contracts efficiently?
Answer: Factory pattern
A factory contract deploys new instances of a target contract on demand, often storing references to deployed clones and reducing code duplication.