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Blockchain Scalability and Interoperability Flashcards

7 cards from real CBCP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Blockchain Scalability and Interoperability flashcards as text

  1. In a Lightning channel, what happens if a party broadcasts an outdated channel state to cheat?

    Answer: The counterparty can use a revocation key to claim all channel funds as a penalty

    Lightning's penalty mechanism lets the wronged party use the revocation secret to sweep the entire channel balance within the timelock.

  2. How do users commonly avoid the long withdrawal delay of an optimistic rollup?

    Answer: By using liquidity providers or fast bridges that front funds on L1 for a fee

    Liquidity providers pay users immediately on L1 and then wait out the challenge period themselves, charging a fee for the service.

  3. How does a Validium differ from a ZK-rollup?

    Answer: Validium stores transaction data off-chain while still using validity proofs

    Validium keeps validity proofs on-chain but stores data off-chain, increasing throughput at the cost of data availability guarantees.

  4. What is a commonly cited risk of rollups that rely on a single centralized sequencer?

    Answer: Transaction censorship, reordering (MEV), or liveness failure if the sequencer goes down

    A single sequencer controls ordering and inclusion, creating censorship, MEV and downtime risks, though forced-inclusion mechanisms can mitigate some of these.

  5. Which category in Vitalik Buterin's classic interoperability taxonomy relies on a trusted party or group to attest to events on another chain?

    Answer: Notary schemes

    Notary schemes use a trusted entity or multisig group to confirm cross-chain events, unlike trust-minimized relays or hash-locking.

  6. BTC Relay on Ethereum is an example of which interoperability approach?

    Answer: Relay/light client that verifies Bitcoin block headers in a smart contract

    BTC Relay stored and verified Bitcoin block headers on Ethereum so contracts could validate Bitcoin transactions via SPV proofs.

  7. What is a key technical challenge introduced by sharding a blockchain?

    Answer: Secure and efficient cross-shard communication and transaction atomicity

    Transactions touching multiple shards require coordination to keep state consistent and atomic, which adds complexity and latency.