Ethereum Smart Contracts BBLC Practice Questions (Page 5)

Questions 21–25

1. 21foundation · easy

   Which of the following is a common security risk in smart contracts that can lead to unexpected behavior when arithmetic operations exceed the maximum or minimum value of a data type?

   • ATimestamp dependence
   • BFront-running attack
   • CInteger overflow/underflow
   • DReentrancy attack
   Reveal Solution Discussion Select an answer first
2. 22application · medium

   A developer has deployed a smart contract and wants to allow another contract to call a function on it. What is required for the second contract to interact with the first?

   • AThe source code of the first contract.
   • BThe private key of the first contract's owner.
   • CA special permission from the Ethereum network.
   • DThe address of the first contract and its ABI.
   Reveal Solution Discussion Select an answer first
4. 23foundation · easy

   Which of the following is a programming language for Ethereum smart contracts that is designed to be more secure and auditable by being intentionally simpler than Solidity?

   • AVyper
   • BSerpent
   • CLLL
   • DBamboo
   Reveal Solution Discussion Select an answer first
5. 24application · medium

   A developer is deploying a smart contract that will be used by multiple other contracts. They want to ensure that only authorized contracts can call a specific function. Which approach should they use?

   • AUse tx.origin to verify the original transaction sender.
   • BUse a modifier that checks msg.sender against a list of authorized contract addresses.
   • CUse a fallback function to handle all calls and check the caller.
   • DUse a public function with no access control, relying on the caller to be honest.
   Reveal Solution Discussion Select an answer first
6. 25expert · hard · select all that apply

   A company is designing a smart contract for a decentralized insurance product. The contract must automatically pay out claims when certain conditions are met. Which features are essential for this use case? Select all that apply.

   • AA selfdestruct function that can be called by anyone to destroy the contract after a claim.
   • BA function that allows the contract to send Ether to the policyholder when the claim is valid.
   • CAn oracle to bring external data (e.g., flight delay information) into the contract.
   • DA state variable that stores the policyholder's address and the payout amount.
   • EA modifier that restricts the claim function to only the policyholder.
   Check answers Discussion Select an answer first