CBSA Consensus Mechanisms 3

Question 1

In the Tendermint consensus protocol, what happens if a proposer fails to broadcast a block within the timeout period?

Accepted Answer

Validators vote nil and the round advances to a new proposer

Answer

The network halts until the proposer recovers

Answer

The previous block is re-proposed by another validator

Answer

A new genesis block is created

Question 2

Stellar's Federated Byzantine Agreement (FBA) differs from classical BFT because:

Accepted Answer

Each node defines its own quorum slice, enabling decentralized trust

Answer

It requires all nodes to agree on the same validator set

Answer

It uses Proof of Work as a fallback mechanism

Answer

It only works in permissioned blockchain networks

Question 3

Which consensus mechanism does Avalanche use to achieve sub-second finality?

Accepted Answer

Metastable consensus via repeated random subsampling of validators

Answer

Classical BFT with an all-to-all broadcast

Answer

Longest-chain rule with 6-block confirmations

Answer

Delegated voting through elected committee

Question 4

In blockchain consensus, what does 'liveness' guarantee?

Accepted Answer

That the network will eventually make progress and commit new transactions

Answer

That no two nodes ever commit conflicting blocks

Answer

That all nodes maintain identical copies of the ledger at all times

Answer

That validators are always online and responsive

Question 5

A blockchain architect needs deterministic finality with high throughput for a consortium supply chain network with 20 known participants. Which consensus is most appropriate?

Accepted Answer

BFT-based consensus (e.g., PBFT or Raft)

Answer

Nakamoto Proof of Work

Answer

Delegated Proof of Stake with public voting

Answer

Proof of Elapsed Time (PoET)

Question 6

What role does a 'proposer' play in most BFT consensus protocols?

Accepted Answer

It collects and orders transactions into a candidate block for validators to vote on

Answer

It verifies the digital signatures of all transactions in a block

Answer

It adjusts the mining difficulty target for the network

Answer

It distributes validator rewards at the end of each epoch

Question 7

Proof of Elapsed Time (PoET), developed by Intel, achieves random leader election by:

Accepted Answer

Using Intel SGX trusted execution environments to generate verifiable random wait times

Answer

Requiring validators to submit zero-knowledge proofs of computation

Answer

Hashing validator public keys with the previous block hash

Answer

Weighting selection probability by validator stake amount