Blockchain Technology Architecture and Platforms 5

Question 1

What is 'slashing' in Proof of Stake consensus mechanisms?

Accepted Answer

Penalizing validators by destroying a portion of their staked tokens for provably malicious behavior

Answer

Slashing is a penalty mechanism that burns a portion (or all) of a validator's staked tokens if they double-sign blocks or attempt to attack the network.

Question 2

What is a 'private blockchain' and what is its primary use case?

Accepted Answer

A fully controlled blockchain where access is restricted to a single organization for internal business processes

Answer

A private blockchain is centrally controlled by one organization, used primarily for internal data management, auditability, or process automation where public access is unnecessary.

Question 3

What is the 'Block Header' in blockchain architecture and what data does it typically contain?

Accepted Answer

Metadata including the previous block hash, Merkle root, timestamp, nonce, and difficulty target

Answer

A block header contains metadata that links the block to the chain, including the hash of the previous block, the Merkle root of all transactions, timestamp, and consensus-specific fields.

Question 4

What distinguishes an 'optimistic rollup' from a 'ZK-rollup' as layer-2 scaling solutions?

Accepted Answer

Optimistic rollups assume transactions are valid and use fraud proofs if challenged, while ZK-rollups use cryptographic validity proofs upfront

Answer

Optimistic rollups post transactions assuming validity, allowing a challenge window for fraud proofs, while ZK-rollups attach a cryptographic validity proof with each batch, enabling faster finality.

Question 5

In a Directed Acyclic Graph (DAG) based blockchain architecture like IOTA, how are transactions confirmed?

Accepted Answer

By each new transaction validating two previous transactions, creating a web-like structure instead of a chain

Answer

In DAG architectures like IOTA's Tangle, users must validate two prior transactions when submitting their own, creating a mesh of confirmations rather than a linear chain of blocks.

Blockchain Practice Test

Blockchain Practice Test

Blockchain Technology Architecture and Platforms 5