Blockchain Developer Certification Practice

Which data structure does Ethereum use to store its state?

1. Binary Tree

2. Merkel Patricia Tree

3. Hash Table

4. Array List

The correct answer is: Merkel Patricia Tree

Ethereum uses the Merkle Patricia Tree as its primary data structure to store its state. This structure combines the concepts of both Merkle Trees and Patricia Tries, making it efficient in terms of both storage and retrieval. The Merkle Patricia Tree allows Ethereum to manage its state more effectively by providing features such as improved verification and the ability to quickly update the state. With this structure, each node can represent a different state of the Ethereum network, and the cryptographic hashes associated with the nodes ensure data integrity. This means that any change to the state can be traced and verified, which is essential for maintaining trust in the decentralized network. Additionally, the Merkle Patricia Tree enables efficient proof verification, allowing clients to verify the state of the blockchain quickly without downloading the entire blockchain, which is crucial for scalability. This sophisticated structure supports the complex requirements of smart contracts and decentralized applications by managing accounts, balances, and contract code seamlessly. In contrast, while other data structures like binary trees, hash tables, and array lists have their own use cases, they do not offer the same combination of efficiency, security, and state management capabilities that the Merkle Patricia Tree provides in the context of Ethereum.