Merkle Tree-Based Transaction Verification BDC Practice Questions (Page 3)

Questions 11–15

1. 11foundation · easy

   What property of cryptographic hash functions makes Merkle trees tamper-evident?

   • ADeterminism: the same input always produces the same hash.
   • BCollision resistance: two different inputs can produce the same hash.
   • CPreimage resistance: it is easy to find a hash that matches a given input.
   • DAvalanche effect: a small change in input produces a completely different hash.
   Reveal Solution Discussion Select an answer first
2. 12application · medium

   A full node is constructing a Merkle proof for transaction T in a block with 8 transactions. The leaves are ordered L1..L8, and T is at position L4. Which sibling hashes must be included in the proof?

   • AL3 and L4
   • BL1, L2, L3, L5, L6, L7, L8
   • CL1, L2, L5, L6, L7, L8
   • DL3, the hash of the parent of L1-L2, and the hash of the sibling of the root's child
   Reveal Solution Discussion Select an answer first
4. 13application · medium

   A developer is implementing a Merkle tree and needs to compute a parent node from two child hashes. Which operation is correct?

   • AHash each child separately and concatenate the resulting hashes.
   • BConcatenate the two child hashes and hash the result.
   • CTake the first half of each child hash and concatenate them.
   • DXOR the two child hashes and hash the result.
   Reveal Solution Discussion Select an answer first
5. 14foundation · easy

   In a blockchain block, where is the Merkle root stored?

   • AIn the transaction list, as an extra entry.
   • BIn the block header.
   • CIn the previous block's header.
   • DIn the first transaction of the block.
   Reveal Solution Discussion Select an answer first
6. 15foundation · easy

   What is the first step in constructing a Merkle tree from a list of transactions?

   • ACreate a binary tree of transactions and then hash the root.
   • BCompute the cryptographic hash of each transaction to create the leaf nodes.
   • CSort the transactions and then hash each pair to create internal nodes.
   • DConcatenate all transactions and hash the result to create the root.
   Reveal Solution Discussion Select an answer first