A smart contract uses an external oracle to fetch the price of an asset. The contract then executes trades based on that price. Which vulnerability is most relevant to this design?

Integer overflow in the price calculation.

Oracle manipulation or a single point of failure.

Denial of service due to gas limits in the oracle call.

Reentrancy in the trade execution function.

A developer discovers a critical vulnerability in a deployed smart contract that has already processed significant funds. The contract is immutable, and there is no upgrade mechanism. Which action is most appropriate?

Use a selfdestruct function to destroy the contract and recover funds.

Deploy a new contract and migrate users and funds to it.

Attempt to modify the deployed contract's code directly.

Ignore the vulnerability because the contract is immutable.

A Solidity developer is implementing a function that calculates a user's reward based on a percentage of their deposit. The function uses multiplication and division. Which practice is essential to prevent arithmetic errors?

Use floating-point numbers for the calculation.

Perform multiplication before division to reduce precision loss.

Perform division before multiplication to simplify the calculation.

Round the result to the nearest integer.

A global supply chain dApp records transactions on a public blockchain. The company operates in multiple jurisdictions with conflicting data protection laws. What is the most prudent approach?

Store only non-personal, hashed data on-chain and keep personal data in a compliant off-chain database.

Store all data on-chain and rely on the blockchain's immutability as a legal defense.

Choose one jurisdiction's law and ignore the others.

Use the most restrictive jurisdiction's law for all data globally.

A developer is writing a smart contract that allows users to bid on an auction. The contract stores the highest bid and the bidder's address. The developer wants to prevent front-running attacks. Which design pattern is most effective?

Use a random number to determine the winner.

Make the highest bid public and allow anyone to outbid it.

Use a commit-reveal scheme where bidders submit a hash of their bid first.

Restrict bidding to a whitelist of addresses.

EC-CouncilBlockchain Business Leader Certification

Domain 4Objective 6

Security and Compliance in Smart Contracts BBLC Practice Questions (Page 6)

Part of the Ethereum, Smart Contracts, and dApps domain, which makes up ~14% of our current practice bank.

43questions here

9free pages

6concepts

Questions 26–30

26application · medium
A smart contract uses an external oracle to fetch the price of an asset. The contract then executes trades based on that price. Which vulnerability is most relevant to this design?
Select an answer first
27application · medium
A developer discovers a critical vulnerability in a deployed smart contract that has already processed significant funds. The contract is immutable, and there is no upgrade mechanism. Which action is most appropriate?
Select an answer first
28application · medium
A Solidity developer is implementing a function that calculates a user's reward based on a percentage of their deposit. The function uses multiplication and division. Which practice is essential to prevent arithmetic errors?
Select an answer first
29application · medium
A global supply chain dApp records transactions on a public blockchain. The company operates in multiple jurisdictions with conflicting data protection laws. What is the most prudent approach?
Select an answer first
30expert · hard
A developer is writing a smart contract that allows users to bid on an auction. The contract stores the highest bid and the bidder's address. The developer wants to prevent front-running attacks. Which design pattern is most effective?
Select an answer first

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