Merkle Tree-Based Transaction Verification BDC Practice Questions (Page 1)

Questions 1–5

1. 1application · medium

   A developer is constructing a Merkle tree from an odd number of transactions (e.g., 5). What is the standard approach to derive the Merkle root?

   • ADuplicate the last transaction hash and pair it with itself to create a balanced tree.
   • BConcatenate all five hashes and hash them once.
   • CHash the last transaction with a zero hash.
   • DDiscard the last transaction and build the tree from the remaining four.
   Reveal Solution Discussion Select an answer first
2. 2foundation · easy

   In a Merkle tree used for transaction verification, what is the structure of the tree?

   • AA hierarchical binary tree where each leaf is a hash of a transaction and each non-leaf node is the hash of its two children.
   • BA linear chain where each node is a hash of the previous node and the next transaction.
   • CA tree where each leaf is a transaction and each parent is the hash of all leaves in its subtree.
   • DA binary tree where each node stores the full transaction data and hashes are only used at the root.
   Reveal Solution Discussion Select an answer first
4. 3application · medium

   A security auditor is reviewing a blockchain implementation and wants to confirm that the Merkle tree provides tamper evidence. Which test would best demonstrate this property?

   • AHash the block header and compare it to the previous block's hash
   • BReverse the order of two transactions and observe that the Merkle root remains the same
   • CChange one byte in a single transaction and observe that the Merkle root changes
   • DVerify the digital signature of the block producer
   Reveal Solution Discussion Select an answer first
5. 4application · medium

   A developer is comparing Merkle tree verification to downloading the entire block for a blockchain with 1,000,000 transactions. What is the primary advantage of using a Merkle proof?

   • AIt eliminates the need for cryptographic hashing
   • BIt provides a way to decrypt transaction data
   • CIt requires only about 20 hashes instead of 1,000,000 transactions
   • DIt allows verification without knowing the block header
   Reveal Solution Discussion Select an answer first
6. 5application · medium

   A developer is implementing a Merkle tree and has two child hashes: H(A) and H(B). Which operation correctly produces the parent node?

   • AH(A) + H(B)
   • Bhash( H(A) ) + hash( H(B) )
   • Chash( A + B )
   • Dhash( H(A) + H(B) )
   Reveal Solution Discussion Select an answer first