A developer is debugging a PBFT network with 7 nodes. The primary node is suspected of being Byzantine and sends different pre-prepare messages to different replicas for the same sequence number. The replicas detect the equivocation. What is the correct next step according to the PBFT protocol?

Replicas trigger a view change to replace the primary

Replicas broadcast the equivocation evidence and wait for a majority decision

Replicas accept the first pre-prepare they received

Replicas ignore the pre-prepare and continue waiting for a valid one

EC-CouncilBlockchain Developer Certification

Domain 3Objective 6

Byzantine Fault Tolerant (BFT) Mechanisms BDC Practice Questions (Page 2)

Part of the Bitcoin and Consensus Mechanisms domain, which makes up ~12% of our current practice bank.

35questions here

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Questions 6–10

6application · medium
A government agency is deploying a permissioned blockchain for land registry records. They require that once a transaction is confirmed, it can never be reversed, even if some nodes later behave maliciously. Which property of BFT consensus is most directly responsible for this guarantee?
Select an answer first
7application · medium
A developer is implementing PBFT in a permissioned blockchain. During a normal round, the primary node sends a pre-prepare message to all replicas. After receiving the pre-prepare, each replica validates the message and then broadcasts a prepare message to all other replicas. What is the minimum number of prepare messages (including its own) that a replica must collect to proceed to the commit phase? The network has 4 nodes total.
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8application · medium
A permissioned blockchain network with 100 validator nodes is considering switching from PBFT to a more scalable BFT variant. The network has high transaction volume and needs to reduce communication overhead. Which alternative would best address the scalability concern?
Select an answer first
9foundation · medium
Which of the following correctly describes the phases of the PBFT algorithm in order?
Select an answer first
10expert · hard
A developer is debugging a PBFT network with 7 nodes. The primary node is suspected of being Byzantine and sends different pre-prepare messages to different replicas for the same sequence number. The replicas detect the equivocation. What is the correct next step according to the PBFT protocol?
Select an answer first

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Byzantine Fault Tolerant (BFT) Mechanisms BDC Practice Questions (Page 2)

Questions 6–10

A government agency is deploying a permissioned blockchain for land registry records. They require that once a transaction is confirmed, it can never be reversed, even if some nodes later behave maliciously. Which property of BFT consensus is most directly responsible for this guarantee?

A permissioned blockchain network with 100 validator nodes is considering switching from PBFT to a more scalable BFT variant. The network has high transaction volume and needs to reduce communication overhead. Which alternative would best address the scalability concern?

Which of the following correctly describes the phases of the PBFT algorithm in order?

A developer is debugging a PBFT network with 7 nodes. The primary node is suspected of being Byzantine and sends different pre-prepare messages to different replicas for the same sequence number. The replicas detect the equivocation. What is the correct next step according to the PBFT protocol?

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