A blockchain platform is experiencing performance issues because full nodes must store and verify the entire transaction history. The team wants to allow new nodes to sync faster while maintaining the ability to verify transaction inclusion. Which approach should they adopt?

Use a stronger hash algorithm to compress the blockchain.

Require all nodes to store the full transaction history.

Remove old blocks and only keep the latest block.

Use Merkle proofs to allow new nodes to verify transactions without downloading all historical blocks.

A healthcare consortium wants to perform analytics on patient records stored on a blockchain without exposing the raw data to the analytics provider. Which cryptographic approach would allow computations on the encrypted data?

Hashing the data before analysis

A blockchain engineer is optimizing a lightweight client for a mobile wallet. The client needs to verify that a specific transaction is included in a block without downloading the entire block. Which mechanism should the engineer rely on?

Merkle proof using the block's Merkle root and the transaction's hash path.

Digital signature from the block producer on the transaction hash.

Full block download and recomputation of all transaction hashes.

Querying a full node's API for the transaction status.

In a Merkle tree, what does the Merkle root represent?

The sum of all transaction fees in the block

The final hash that summarizes all transaction hashes in the block

The public key of the block producer

A fintech company is building a blockchain-based payment system. They require that each transaction be verifiable by any participant, but only the sender can authorize it. Which cryptographic mechanism should be used to meet this requirement?

Symmetric encryption of the transaction with a shared secret key.

Message authentication code (MAC) using a shared secret.

Hash of the transaction signed with the recipient's private key.

Digital signatures using the sender's private key, verifiable with the sender's public key.

EC-CouncilBlockchain Business Leader Certification

Domain 2Objective 2

Advanced Cryptographic Mechanisms in Blockchain Security BBLC Practice Questions (Page 8)

Part of the Cryptography and Security in Blockchain domain, which makes up ~13% of our current practice bank.

50questions here

10free pages

9concepts

Questions 36–40

36expert · hard
A blockchain platform is experiencing performance issues because full nodes must store and verify the entire transaction history. The team wants to allow new nodes to sync faster while maintaining the ability to verify transaction inclusion. Which approach should they adopt?
Select an answer first
37application · medium
A healthcare consortium wants to perform analytics on patient records stored on a blockchain without exposing the raw data to the analytics provider. Which cryptographic approach would allow computations on the encrypted data?
Select an answer first
38application · medium
A blockchain engineer is optimizing a lightweight client for a mobile wallet. The client needs to verify that a specific transaction is included in a block without downloading the entire block. Which mechanism should the engineer rely on?
Select an answer first
39foundation · easy
In a Merkle tree, what does the Merkle root represent?
Select an answer first
40application · medium
A fintech company is building a blockchain-based payment system. They require that each transaction be verifiable by any participant, but only the sender can authorize it. Which cryptographic mechanism should be used to meet this requirement?
Select an answer first

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