Blockchain
1. What is a blockchain database?
Answer:
A blockchain database is a decentralized
ledger that records transactions securely across a distributed network.
2. How does blockchain ensure data immutability?
Answer:
Blockchain ensures immutability through
cryptographic hashing and consensus mechanisms, preventing unauthorized
changes.
3. What is the key difference between blockchain and
traditional databases?
Answer:
Blockchain is decentralized and immutable,
while traditional databases are centralized and allow data modification.
4. What are the main components of a blockchain?
Answer:
The main components include blocks,
transactions, cryptographic hashes, nodes, and consensus mechanisms.
5. What is the role of cryptographic hashing in
blockchain?
Answer:
Cryptographic hashing secures data by
converting it into a fixed-length hash, ensuring integrity and preventing
tampering.
6. What are the types of blockchain networks?
Answer:
Public, private, consortium, and hybrid
blockchains.
7. What is a Merkle tree in blockchain?
Answer:
A Merkle tree is a data structure that
helps efficiently verify data integrity in blockchain transactions.
8. How does a consensus mechanism work in blockchain?
Answer:
Consensus mechanisms ensure agreement on
transaction validity among network nodes using methods like PoW or PoS.
9. What is Proof of Work (PoW)?
Answer:
PoW is a consensus mechanism requiring
nodes to solve complex puzzles to validate transactions.
10. What is Proof of Stake (PoS)?
Answer:
PoS selects validators based on their
cryptocurrency holdings rather than computational power.
11. What is the role of a node in blockchain?
Answer:
Nodes maintain a copy of the blockchain and
participate in transaction validation and consensus.
12. What is a smart contract?
Answer:
A smart contract is a self-executing
contract with predefined conditions encoded on the blockchain.
13. What is a blockchain fork?
Answer:
A blockchain fork occurs when a network
splits into two separate chains due to protocol updates or disagreements.
14. How does a private blockchain differ from a public
blockchain?
Answer:
Private blockchains have restricted access,
whereas public blockchains are open to anyone.
15. What is a consortium blockchain?
Answer:
A consortium blockchain is a
semi-decentralized network controlled by multiple organizations.
16. What is the double-spending problem in blockchain?
Answer:
The double-spending problem occurs when a
digital asset is spent more than once, prevented by consensus mechanisms.
17. What is a genesis block in blockchain?
Answer:
The genesis block is the first block in a
blockchain network.
18. How does Ethereum differ from Bitcoin?
Answer:
Ethereum supports smart contracts, whereas
Bitcoin primarily functions as digital currency.
19. What is gas in Ethereum?
Answer:
Gas is the fee required to execute
transactions and smart contracts on the Ethereum network.
20. How does sharding improve blockchain scalability?
Answer:
Sharding partitions the blockchain into
smaller segments to improve transaction speed and efficiency.
21. What are layer 2 solutions in blockchain?
Answer:
Layer 2 solutions enhance scalability by
processing transactions off-chain before finalizing them on the main chain.
22. What is Byzantine Fault Tolerance (BFT)?
Answer:
BFT ensures that a blockchain network can
function correctly even if some nodes act maliciously.
23. What are some real-world use cases of blockchain
beyond cryptocurrencies?
Answer:
Supply chain tracking, healthcare records,
identity management, and financial services.
24. What is Hyperledger Fabric?
Answer:
Hyperledger Fabric is a permissioned
blockchain framework designed for enterprise use.
25. What is tokenization in blockchain?
Answer:
Tokenization converts real-world assets
into digital tokens on a blockchain.
26. What is a decentralized application (DApp)?
Answer:
A DApp is an application that runs on a
decentralized blockchain network instead of a centralized server.
27. What is an oracle in blockchain?
Answer:
An oracle is an external data source that
feeds real-world information into smart contracts.
28. How does zero-knowledge proof work in blockchain?
Answer:
Zero-knowledge proofs enable data
verification without revealing the actual data.
29. What are Non-Fungible Tokens (NFTs)?
Answer:
NFTs are unique digital assets stored on a
blockchain, representing ownership of items like art and collectibles.
30. What is a 51% attack in blockchain?
Answer:
A 51% attack occurs when a single entity controls
over half of a blockchain's mining power, potentially altering transactions.
31. What is the difference between hot and cold wallets?
Answer:
Hot wallets are connected to the internet,
while cold wallets store cryptocurrencies offline for security.
32. What is a hash function in blockchain?
Answer:
A hash function converts input data into a
fixed-length string, ensuring security and data integrity.
33. How is blockchain used in healthcare?
Answer:
Blockchain secures patient records, ensures
data integrity, and enables secure sharing of medical information.
34. What is a mempool in blockchain?
Answer:
A mempool is a waiting area for unconfirmed
transactions before they are added to a block.
35. What are the limitations of blockchain technology?
Answer:
Scalability issues, high energy
consumption, regulatory concerns, and data privacy challenges.
36. How does blockchain impact cybersecurity?
Answer:
Blockchain enhances security by eliminating
single points of failure and reducing hacking risks.
37. What is the InterPlanetary File System (IPFS)?
Answer:
IPFS is a decentralized protocol for
storing and sharing files securely across a blockchain network.
38. What is Solidity?
Answer:
Solidity is a programming language used to
write smart contracts on Ethereum.
39. How does blockchain ensure data transparency?
Answer:
Blockchain maintains a public ledger where
all transactions are verifiable and traceable.
40. What is a sidechain in blockchain?
Answer:
A sidechain is a separate blockchain linked
to the main chain, enabling scalability and flexibility.
41. What is the difference between permissioned and
permissionless blockchains?
Answer:
Permissioned blockchains restrict access to
certain users, while permissionless blockchains are open to everyone.
42. What is a block header in blockchain?
Answer:
A block header contains metadata like the
previous block hash, Merkle root, and timestamp.
43. How does blockchain prevent data tampering?
Answer:
Blockchain prevents tampering through
cryptographic hashing, decentralized consensus, and immutability.
44. What is the difference between a soft fork and a hard
fork?
Answer:
A soft fork is a backward-compatible
upgrade, while a hard fork creates a separate chain requiring all nodes to
upgrade.
45. How does blockchain enhance supply chain management?
Answer:
Blockchain improves transparency,
traceability, and security in supply chains by providing an immutable ledger.
46. What is the Lightning Network in blockchain?
Answer:
The Lightning Network is a Layer 2 solution
that enables faster and cheaper Bitcoin transactions.
47. What is Directed Acyclic Graph (DAG) in blockchain?
Answer:
DAG is a non-linear data structure used in
some blockchain alternatives like IOTA to improve scalability.
48. What are state channels in blockchain?
Answer:
State channels allow off-chain transactions
to reduce blockchain congestion and improve efficiency.
49. What is a blockchain consensus attack?
Answer:
A consensus attack occurs when malicious entities
manipulate blockchain validation processes, such as 51% attacks.
50. How does blockchain handle identity management?
Answer:
Blockchain enables secure and decentralized
identity management by storing encrypted identity records.
51. What is the difference between fungible and
non-fungible tokens?
Answer:
Fungible tokens are interchangeable (e.g.,
cryptocurrencies), whereas non-fungible tokens (NFTs) are unique digital
assets.
52. How does blockchain impact financial transactions?
Answer:
Blockchain enables fast, transparent, and
low-cost financial transactions without intermediaries.
53. What is a DAO (Decentralized Autonomous Organization)?
Answer:
A DAO is an organization run by smart
contracts and governed by token holders without central authority.
54. How does blockchain improve digital voting systems?
Answer:
Blockchain enhances voting security,
transparency, and prevents fraud by providing immutable election records.
55. What is staking in blockchain?
Answer:
Staking involves locking up cryptocurrency
to support network operations and earn rewards.
56. What is slashing in Proof of Stake (PoS) blockchains?
Answer:
Slashing is a penalty imposed on validators
who behave maliciously or fail to validate transactions correctly.
57. How do rollups improve blockchain scalability?
Answer:
Rollups batch multiple transactions into a
single one, reducing congestion and gas fees on the main chain.
58. What is a block size limit in blockchain?
Answer:
The block size limit restricts the amount
of data a block can hold, affecting transaction throughput.
59. How does blockchain facilitate cross-border payments?
Answer:
Blockchain enables fast and cost-effective
cross-border transactions without relying on banks.
60. What are hybrid blockchains?
Answer:
Hybrid blockchains combine features of both
public and private blockchains for increased flexibility.