Cryptoasset Anti-Financial Crime Specialist (CCAS) Certification Practice Test

Which function is provided by a blockchain oracle?

1. Displaying transactions from Ethereum

2. Showing confirmation times of Ethereum transactions

3. Posting real-time USD/ETH prices

4. Aggregating the number of Ethereum wallets

The correct answer is: Posting real-time USD/ETH prices

A blockchain oracle primarily serves as a bridge between smart contracts and real-world data. It is responsible for providing external information that smart contracts cannot access on their own due to the inherent limitations of blockchain technology, which is designed to be secure and decentralized. The correct answer highlights that oracles post real-time USD/ETH prices. This function is crucial because many decentralized applications (dApps) that operate on the Ethereum blockchain require current market data to execute transactions or to trigger specific actions within smart contracts based on fluctuations in price. For instance, if a smart contract is programmed to execute a trade based on the price of ETH in USD, it needs an oracle to feed in that real-time data, ensuring that the contract can respond appropriately to market conditions. In contrast, the other options focus on functionalities that do not align with the primary role of an oracle. While displaying transactions, showing confirmation times, or aggregating wallet numbers might be useful metrics, they do not represent the core purpose of oracles, which is to connect on-chain platforms with off-chain information, particularly dynamic data such as prices, that can influence how smart contracts operate in real-time.