Blockchain Scalability and Layer 2 Solutions Flashcards
7 cards from real Blockchain Technology 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 Layer 2 Solutions flashcards as text
What is the 'data availability' problem in the context of Layer 2 rollups?
Answer: Ensuring that transaction data is published and accessible so anyone can reconstruct the rollup state and verify or challenge it
If transaction data is withheld, users cannot independently verify the rollup state or generate fraud/validity proofs, making data availability a critical security property.
In ZK-Rollup terminology, what does the 'sequencer' do?
Answer: Orders, batches, and submits transactions to Layer 1 on behalf of users
The sequencer collects user transactions, determines their order, bundles them into batches, and posts batches (along with proofs) to Layer 1.
What is Plasma in the context of Ethereum scalability?
Answer: A framework for creating child chains anchored to Ethereum, where only block roots are submitted to the main chain
Plasma allows the creation of child chains that periodically commit Merkle roots of their state to Ethereum, enabling high-throughput processing with Ethereum as the final arbiter.
What is the primary function of a cross-chain bridge in a multi-chain ecosystem?
Answer: To enable the transfer of assets and data between two separate blockchain networks
A cross-chain bridge locks or burns assets on one chain and mints or releases equivalent assets on another chain, enabling interoperability between separate blockchains.
What is the standard challenge period duration used by most Optimistic Rollups like Arbitrum and Optimism?
Answer: 7 days
Most Optimistic Rollups use a 7-day challenge window to give honest validators sufficient time to detect and prove fraudulent transactions before they are finalized.
Which scaling approach is used by Validium, differentiating it from standard ZK-Rollups?
Answer: Validium stores transaction data off-chain with a data availability committee rather than posting it to Layer 1
Validium uses validity proofs like ZK-Rollups but keeps transaction data off-chain, relying on a data availability committee, which reduces costs but introduces a data availability trust assumption.
What major vulnerability class has most frequently exploited cross-chain bridges, resulting in hundreds of millions in losses?
Answer: Flaws in signature verification and validator key management
High-profile bridge hacks like Ronin and Wormhole exploited weaknesses in multi-signature schemes, private key management, or signature verification logic used to authorize cross-chain messages.