Token Standards and Creation 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 Token Standards and Creation flashcards as text
What is a key advantage of storing NFT metadata on IPFS rather than a centralized HTTP server?
Answer: Content-addressed IPFS hashes ensure metadata is immutable and tamper-evident
IPFS uses content hashes, so any change to metadata changes the address, making tampering detectable.
What does 'fully on-chain' NFT metadata mean?
Answer: The metadata and often the image are stored directly in contract storage, not via external links
On-chain metadata is encoded in the contract itself (e.g., base64 data URIs), removing external dependencies.
In ERC-777, what is the role of an 'operator'?
Answer: An address authorized to send tokens on behalf of a holder
ERC-777 operators are addresses a holder authorizes to move their tokens, generalizing the allowance concept.
What hook does ERC-777 introduce that can create a reentrancy risk if not handled carefully?
Answer: tokensReceived, called on the recipient during a transfer
ERC-777's tokensReceived hook gives recipients control flow mid-transfer, which can enable reentrancy attacks.
Why is the checks-effects-interactions pattern important when writing a token's transfer logic?
Answer: It updates state before external calls to prevent reentrancy exploits
Updating balances before any external call ensures a reentrant call sees the already-modified state.
What is the purpose of a token's totalSupply() function for token economics transparency?
Answer: It reports the total number of tokens currently in existence
totalSupply() returns the aggregate amount of tokens that currently exist across all addresses.
When creating a token on an EVM-compatible L2 like Arbitrum or Optimism, what remains true compared to Ethereum mainnet?
Answer: The same ERC-20/ERC-721 standards and Solidity bytecode apply
EVM-compatible L2s run the same bytecode, so identical token standards and contracts work with lower fees.