A consortium of banks runs a permissioned blockchain for interbank transfers. One member bank has been compromised, and the attacker is using that bank's node to submit fraudulent transactions. The consortium must protect the network while maintaining the compromised bank's ability to participate after recovery. What is the most appropriate response?

Immediately revoke the compromised node's access and require the bank to undergo a security audit before re-admission.

Let the compromised node continue operating but monitor its transactions closely.

Fork the blockchain to remove the compromised bank from the network permanently.

Ignore the incident because the consensus mechanism will reject fraudulent transactions.

A global blockchain payment company must comply with GDPR in Europe and the CCPA in California. They store customer transaction data on a public blockchain. The legal team says they need to ensure data erasure rights. What is the most practical approach?

Use a private blockchain with a centralized administrator who can delete data

Store only hashed or encrypted personal data on-chain and keep raw data in a separate, deletable database

Stop using blockchain and use a traditional database

Anonymize all personal data before storing on-chain

A blockchain startup has just suffered a major security breach where an attacker exploited a smart contract vulnerability and stole $10M in tokens. The team must decide how to respond. They have a limited budget and want to minimize reputational damage. Which response strategy is most appropriate?

Immediately fork the blockchain to reverse the stolen transactions

Immediately pause the affected contract, conduct a thorough forensic analysis, and then publish a transparent post-mortem

Quietly fix the vulnerability and resume operations without public disclosure

Offer a bug bounty to the attacker to return the funds

A blockchain network uses a proof-of-stake consensus algorithm. The security team wants to mitigate the risk of a long-range attack where an attacker creates an alternative chain from an early block. Which measure is most effective?

Require validators to lock their stake for a longer period

Use a shorter block time to finalize transactions faster

Use checkpointing at regular intervals to finalize blocks

Increase the block size to process more transactions

EC-CouncilBlockchain Fintech Certification

Domain 8Objective 3

Mitigating Blockchain Attacks and Security Practices BFC Practice Questions (Page 4)

Part of the Governance, Compliance, and Risk Management domain, which makes up ~12% of our current practice bank.

48questions here

10free pages

8concepts

Questions 16–20

16foundation · easy
Which hashing property ensures that a small change in the input produces a completely different hash output, making it difficult to find two inputs with the same hash?
Select an answer first
17expert · hard
A consortium of banks runs a permissioned blockchain for interbank transfers. One member bank has been compromised, and the attacker is using that bank's node to submit fraudulent transactions. The consortium must protect the network while maintaining the compromised bank's ability to participate after recovery. What is the most appropriate response?
Select an answer first
18expert · hard
A global blockchain payment company must comply with GDPR in Europe and the CCPA in California. They store customer transaction data on a public blockchain. The legal team says they need to ensure data erasure rights. What is the most practical approach?
Select an answer first
19expert · hard
A blockchain startup has just suffered a major security breach where an attacker exploited a smart contract vulnerability and stole $10M in tokens. The team must decide how to respond. They have a limited budget and want to minimize reputational damage. Which response strategy is most appropriate?
Select an answer first
20application · medium
A blockchain network uses a proof-of-stake consensus algorithm. The security team wants to mitigate the risk of a long-range attack where an attacker creates an alternative chain from an early block. Which measure is most effective?
Select an answer first

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Mitigating Blockchain Attacks and Security Practices BFC Practice Questions (Page 4)

Questions 16–20

Which hashing property ensures that a small change in the input produces a completely different hash output, making it difficult to find two inputs with the same hash?

A global blockchain payment company must comply with GDPR in Europe and the CCPA in California. They store customer transaction data on a public blockchain. The legal team says they need to ensure data erasure rights. What is the most practical approach?

A blockchain startup has just suffered a major security breach where an attacker exploited a smart contract vulnerability and stole $10M in tokens. The team must decide how to respond. They have a limited budget and want to minimize reputational damage. Which response strategy is most appropriate?

A blockchain network uses a proof-of-stake consensus algorithm. The security team wants to mitigate the risk of a long-range attack where an attacker creates an alternative chain from an early block. Which measure is most effective?

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