Blockchain Interview Questions and Answers
Experienced / Expert level questions & answers
Ques 1. What is the role of miners in blockchain?
Miners are participants in a blockchain network who validate transactions and add them to the blockchain. They use computational power to solve complex mathematical problems and reach consensus on the state of the ledger.
Ques 2. What is a 51% attack, and how can it be prevented?
A 51% attack occurs when an entity controls more than 50% of a blockchain's mining power, allowing them to manipulate transactions. Prevention measures include using consensus algorithms, such as Proof of Work or Proof of Stake.
Ques 3. What is the purpose of the nonce in Proof of Work consensus?
The nonce is a number used in mining to find a hash value that meets specific criteria. Miners adjust the nonce value until they find a hash that satisfies the difficulty level set by the network, thus creating a new block.
Ques 4. What is a hard fork in blockchain?
A hard fork is a significant and incompatible change to the protocol of a blockchain network, resulting in a divergence in the blockchain's transaction history. It requires all nodes to upgrade to the latest software version.
Ques 5. What is a sidechain in blockchain?
A sidechain is a separate blockchain that is interoperable with a main blockchain. It allows for the transfer of assets between the sidechain and the main chain, enabling the development of specific features or scalability solutions.
Ques 6. What is the concept of atomic swaps in blockchain?
Atomic swaps enable the direct exchange of one cryptocurrency for another between users without the need for an intermediary or centralized exchange. It occurs atomically, meaning the swap either happens in full or not at all.
Ques 7. Explain the concept of sharding in blockchain.
Sharding is a scaling technique that involves breaking the blockchain into smaller parts called shards. Each shard processes its transactions, improving the overall scalability and efficiency of the blockchain network.
Ques 8. What is the Byzantine Generals Problem in the context of blockchain?
The Byzantine Generals Problem refers to the challenge of achieving consensus in a distributed system where nodes may behave maliciously or fail to communicate reliably. Blockchain consensus algorithms address this problem to ensure network security.
Ques 9. Explain the concept of zero-knowledge proofs in blockchain.
Zero-knowledge proofs allow one party to prove the authenticity of information to another party without revealing any details about the information itself. This enhances privacy and security in blockchain transactions.
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