Interoperability Challenges in Blockchain Systems BFC Practice Questions (Page 4)

Questions 16–20

1. 16foundation · easy

   Why do validator trust assumptions create security challenges in cross-chain communication?

   • AThey rely on a set of validators to honestly report events on one chain to another
   • BThey require all validators to use the same hardware
   • CThey increase the block size of the destination chain
   • DThey eliminate the need for cryptographic signatures
   Reveal Solution Discussion Select an answer first
2. 17application · medium

   A security team is reviewing a cross-chain bridge that uses a set of validators to lock assets on one chain and mint wrapped tokens on another. They identify a vulnerability where a malicious smart contract on the target chain could exploit the minting function to create tokens without a corresponding lock. Which type of challenge does this vulnerability represent?

   • ASmart contract vulnerability
   • BData format inconsistency
   • CConsensus mechanism difference
   • DValidator trust assumption
   Reveal Solution Discussion Select an answer first
4. 18expert · hard

   A consortium of banks is designing a cross-chain bridge between a permissioned blockchain and a public blockchain. The bridge relies on a set of validators that sign off on lock-and-mint operations. A security auditor warns that if a majority of these validators collude, they could sign a fraudulent mint on the public chain without a corresponding lock on the permissioned chain, enabling double-spending. The consortium wants to reduce this risk without sacrificing the bridge's usability. Which approach best mitigates the validator collusion risk?

   • AUse a sidechain that does not require external validators, relying solely on the permissioned chain's consensus.
   • BIncrease the number of validators and require a supermajority (e.g., 80%) to sign off on any mint operation.
   • CReplace the validator set with a single trusted notary to simplify the signing process.
   • DEliminate the bridge and use atomic swaps for all cross-chain transfers.
   Reveal Solution Discussion Select an answer first
5. 19foundation · easy

   Why is blockchain interoperability considered essential for integrating blockchain into financial infrastructure?

   • AIt enables seamless transfer of assets and data across different blockchain networks
   • BIt eliminates the need for regulatory compliance in blockchain transactions
   • CIt guarantees that all blockchain transactions are irreversible
   • DIt allows financial institutions to use a single blockchain for all their operations
   Reveal Solution Discussion Select an answer first
6. 20expert · hard

   A multinational bank is implementing a blockchain interoperability solution that enables cross-border payments. The solution involves multiple blockchain networks in different countries. The bank must comply with GDPR for European customers and the Bank Secrecy Act (BSA) in the US. The compliance team is concerned about how transaction data is stored and shared across chains. Which approach best balances data privacy and AML compliance?

   • AUse a notary scheme that stores all transaction data with the notary, who is responsible for compliance.
   • BStore all transaction data on-chain in a public blockchain to ensure transparency for regulators.
   • CRoute all transactions through a single offshore blockchain to avoid GDPR and BSA jurisdiction.
   • DUse private, permissioned blockchains in each jurisdiction and share only hashed or encrypted transaction references across chains.
   Reveal Solution Discussion Select an answer first