CBCP Ethereum 4

Question 1

What is the 'Spurious Dragon' hard fork best known for introducing?

Accepted Answer

EIP-161 state-clearing which removed empty accounts, and EIP-170 which capped contract code size at 24KB

Answer

Spurious Dragon (Nov 2016) followed the Shanghai DoS attacks and cleaned up empty accounts while capping bytecode size.

Question 2

Which cryptographic curve does Ethereum use for signing transactions?

Accepted Answer

secp256k1

Answer

Ethereum uses the secp256k1 elliptic curve for ECDSA signatures, the same curve used by Bitcoin.

Question 3

What is a 'proxy pattern' in Ethereum smart contract upgradability?

Accepted Answer

A contract that delegates calls to an implementation contract, allowing logic to be upgraded without changing the proxy's address

Answer

The proxy holds state and forwards calls via DELEGATECALL to an upgradeable logic contract, preserving the original address.

Question 4

In Ethereum's ERC-721 standard, what does the tokenURI function return?

Accepted Answer

A URI pointing to a JSON file describing the NFT's metadata including name, image, and attributes

Answer

tokenURI returns a URL (often IPFS or HTTPS) to a JSON metadata file following the ERC-721 metadata standard.

Question 5

What problem does EIP-712 (Typed Structured Data Hashing and Signing) solve?

Accepted Answer

Prevents signature replay across different contracts and chains by encoding domain-specific context into signed messages

Answer

EIP-712 binds a signature to a specific contract, chain, and structured payload, making phishing and replay attacks harder.

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