Network Layer, Consensus, Smart Contract, and Node Security Best Practices BDC Practice Questions (Page 7)

Questions 31–35

1. 31application · medium

   A smart contract development team has just completed a major upgrade to a DeFi protocol. They want to detect potential security issues before deployment. Which approach is most effective for identifying vulnerabilities in the new contract code?

   • ADeploy the contract to mainnet immediately and rely on user reports to find issues.
   • BOnly use a single automated scanning tool and trust its results completely.
   • CTest the contract only on a local development network without any external review.
   • DRun a combination of static analysis tools, manual code review, and a bug bounty program before the mainnet deployment.
   Reveal Solution Discussion Select an answer first
2. 32foundation · easy

   In a blockchain network, which mitigation is specifically effective against eclipse attacks?

   • AIncreasing block size
   • BImplementing proof-of-work with higher difficulty
   • CUsing a diverse set of peer connections and monitoring for duplicate IPs
   • DEncrypting all network traffic with TLS
   Reveal Solution Discussion Select an answer first
4. 33expert · hard

   A security team is conducting a threat model for a cross-chain bridge that uses a set of validators to sign off on transfers. The team identifies a risk where a malicious validator could sign conflicting transactions for the same asset on different chains, causing double-spending. Which combination of mitigations would be most effective in preventing this specific attack?

   • AAllow any single validator to sign transfers and rely on the receiving chain to detect double-spending.
   • BUse a simple majority of validators without any penalty for misbehavior.
   • CIncrease the number of validators to make it harder for an attacker to control the bridge.
   • DUse a threshold signature scheme where a quorum of validators must sign, and implement slashing conditions for validators who sign conflicting messages.
   Reveal Solution Discussion Select an answer first
5. 34foundation · easy

   What is the primary purpose of input validation in smart contract functions?

   • ATo reduce gas costs
   • BTo ensure the contract only processes valid and expected data
   • CTo make the contract upgradeable
   • DTo improve the user interface
   Reveal Solution Discussion Select an answer first
6. 35expert · hard

   A smart contract uses a proxy pattern for upgradeability. The implementation contract has a function that can be called directly, bypassing the proxy's access control. What is the most effective way to prevent this?

   • ARely on the proxy's access control to protect the implementation.
   • BAdd a modifier to the implementation contract that only allows calls from the proxy contract.
   • CMake the implementation contract's functions private.
   • DDelete the implementation contract after deployment.
   Reveal Solution Discussion Select an answer first