Blockchain Interview Questions and Answers | Blockchain Technology | Blockchain Tutorial | Edureka

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2. Agenda Blockchain In Market General Blockchain Questions Advanced Blockchain Questions www.edureka.co/blockchain-training Blockchain Certification Training

3. Blockchain In Market Copyright © 2017, edureka and/or its affiliates. All rights reserved.

4. Blockchain In Market Note: Data retrieved in mid December, Source: Linkedin www.edureka.co/blockchain-training Blockchain Certification Training

5. Blockchain Job Trends There are currently 14 Open Jobs for every Blockchain Engineer Blockchain Job Market Is Forecast To Grow 16X In The Next 7 Years www.edureka.co/blockchain-training Blockchain Certification Training

6. Blockchain Interview Questions Copyright © 2017, edureka and/or its affiliates. All rights reserved.

8. 01 General Interview Questions 02 Advanced Interview Questions Copyright © 2017, edureka and/or its affiliates. All rights reserved.

9. Blockchain: General Interview Questions 1. What do you know about Blockchain? www.edureka.co/blockchain-training Blockchain Certification Training

10. Blockchain: General Interview Questions 1. What do you know about Blockchain? ➢ Blockchain is a decentralized distributed database of immutable records ➢ The transactions are protected by strong cryptographic algorithms ➢ Every new record is validated across the distributed network before it is stored in a block ➢ To access the data of the first block, you have to traverse from the last created block to the first block www.edureka.co/blockchain-training Blockchain Certification Training

11. Blockchain: General Interview Questions 2. What is the principle on which blockchain technology is based on? www.edureka.co/blockchain-training Blockchain Certification Training

12. Blockchain: General Interview Questions 2. What is the principle on which blockchain technology is based on? Blockchain is based on the Distributed ledger technology which aims to provide a shared single source of truth being distributed across the network www.edureka.co/blockchain-training Blockchain Certification Training

13. Blockchain: General Interview Questions 3. What are the different types of Blockchains? www.edureka.co/blockchain-training Blockchain Certification Training

14. Blockchain: General Interview Questions 3. What are the different types of Blockchains? Public Consortium Private www.edureka.co/blockchain-training Blockchain Certification Training

15. Blockchain: General Interview Questions 4. Why is Blockchain a trusted approach? www.edureka.co/blockchain-training Blockchain Certification Training

16. Blockchain: General Interview Questions 4. Why is Blockchain a trusted approach? ➢ Blockchain is an immutable ledger. The transactional records are secured by strong cryptographic algorithms. Also, every participants have the shared single source of truth ➢ It distributes trust among different actors in the system via an economic game that incentivizes actors to cooperate with the rules defined by the protocol www.edureka.co/blockchain-training Blockchain Certification Training

17. Blockchain: General Interview Questions 5. What type of records can be kept in a Blockchain? Is there any restriction on same? www.edureka.co/blockchain-training Blockchain Certification Training

18. Blockchain: General Interview Questions 5. What type of records can be kept in a Blockchain? Is there any restriction on same? There is no restriction on keeping records of any type in the Blockchain approach. Industries are using Blockchain for securing all types of records. The common types of records (to name a few) that can be kept on the Blockchains are: ➢ Records of medical transactions ➢ Identity management ➢ Transaction processing ➢ Business transactions, ➢ Management activities ➢ Documentation www.edureka.co/blockchain-training Blockchain Certification Training

19. Blockchain: General Interview Questions 6. Blockchain is a decentralized database. How does it differ from traditional databases? www.edureka.co/blockchain-training Blockchain Certification Training

20. Blockchain: General Interview Questions 6. Blockchain is a decentralized database. How does it differ from traditional databases? Properties Blockchain Traditional Database Records Records are stored in a decentralized database Records are centralized Operations Only Insert Operations Can perform C.R.U.D. operations Master Slave Multi-Master Replication Full Replication of block on every peer Distributed Transactions (2 phase commit) Consensus Majority of peers agree on the outcome of transactions Integrity Constraints Invariants Anybody can validate transactions across the network www.edureka.co/blockchain-training Blockchain Certification Training

21. Blockchain: General Interview Questions 7. What are the key features of Blockchain? www.edureka.co/blockchain-training Blockchain Certification Training

22. Blockchain: General Interview Questions 7. What are the key features of Blockchain? Key features of blockchain: ➢ Decentralized Systems ➢ Distributed ledger ➢ Immutability ➢ Safer & Secure Ecosystem ➢ Minting (Blockchain specific) www.edureka.co/blockchain-training Blockchain Certification Training

23. Blockchain: General Interview Questions 8. What is encryption? What is its role in Blockchain? www.edureka.co/blockchain-training Blockchain Certification Training

24. Blockchain: General Interview Questions 8. What is encryption? What is its role in Blockchain? Data security always matters. Encryption is basically an approach that helps organizations to keep their data secure. The encrypted data is encoded or changed up to some extent before it is sent out of a network by the sender and only authorized parties can access that information. In Blockchain, this approach is useful because it simply adds more to the overall security and authenticity of blocks and helps to keep them secure. www.edureka.co/blockchain-training Blockchain Certification Training

25. Blockchain: General Interview Questions 9. What do you mean by blocks in the blockchain technology? www.edureka.co/blockchain-training Blockchain Certification Training

26. Blockchain: General Interview Questions 9. What do you mean by blocks in the blockchain technology? Blockchain consists of a list of records. Such records are stored in blocks. These blocks are in turn linked with other blocks and hence constitute a chain called Blockchain. New Blocks To access data of the first ever created block, you have to traverse from the last created block to the first block www.edureka.co/blockchain-training Blockchain Certification Training

27. Blockchain: General Interview Questions 10. How does a block is recognized in the Blockchain approach? www.edureka.co/blockchain-training Blockchain Certification Training

28. Blockchain: General Interview Questions 10. How does a block is recognized in the Blockchain approach? Every block in this online ledger basically consists of a hash pointer which acts as a link to the block which is prior to it, transaction data and in fact a stamp of time. www.edureka.co/blockchain-training Blockchain Certification Training

29. Blockchain: General Interview Questions 11. Is it possible to modify the data once it is written in a block? www.edureka.co/blockchain-training Blockchain Certification Training

30. Blockchain: General Interview Questions 11. Is it possible to modify the data once it is written in a block? No, it's not possible to do so. As all the records are secured by strong cryptographic algorithms and any change in any of the records will consequently result in the change in the hash of the records. www.edureka.co/blockchain-training Blockchain Certification Training

31. Blockchain: General Interview Questions 12. What are Block Identifiers? www.edureka.co/blockchain-training Blockchain Certification Training

32. Blockchain: General Interview Questions 12. What are Block Identifiers? Block identifiers are the means to identify a block in the blockchain. The block can be identified by the block header hash and the block height. www.edureka.co/blockchain-training Blockchain Certification Training

33. Blockchain: General Interview Questions 13. Is it possible in Blockchain to remove one or more block from the network? www.edureka.co/blockchain-training Blockchain Certification Training

34. Blockchain: General Interview Questions 13. Is it possible in Blockchain to remove one or more block from the network? No, it can’t be done. Since all the blocks in the blockchain are linked to the hash of the previous block. Removing any block from the blockchain will disrupt the header hash of all the previous blocks. www.edureka.co/blockchain-training Blockchain Certification Training

35. Blockchain: General Interview Questions 14. What exactly do you know about the security of a block? www.edureka.co/blockchain-training Blockchain Certification Training

36. Blockchain: General Interview Questions 14. What exactly do you know about the security of a block? Well, a block or the entire blockchain is protected by a strong cryptographic hash algorithm. Each block has a unique hash pointer. Any modification in the block constituents will result in the change in the hash identifier of the block. Thus, one needs not to worry about the safety as well as the security of data that is present in a block. www.edureka.co/blockchain-training Blockchain Certification Training

37. Blockchain: General Interview Questions 15. What are Merkle trees? How important are Merkle trees in Blockchains? www.edureka.co/blockchain-training Blockchain Certification Training

38. Blockchain: General Interview Questions 15. What are Merkle trees? How important are Merkle trees in Blockchains? Merkle Tree also known as 'hash tree' is a data structure in cryptography in which each leaf node is a hash of a block of data, and each non-leaf node is a hash of its child nodes. Merkle Root Block The benefit of using the Merkle Tree in blockchain is that instead of downloading every transaction and every block, a “light client” can only download the chain of block headers. Merkle Tree www.edureka.co/blockchain-training Blockchain Certification Training

39. Blockchain: General Interview Questions 16. What is a ledger? Is Blockchain an incorruptible ledger? www.edureka.co/blockchain-training Blockchain Certification Training

40. Blockchain: General Interview Questions 16. What is a ledger? Is Blockchain an incorruptible ledger? Blockchain is considered incorruptible “To take over the network, an attacker would have to control more than 50 percent of its total computing power,” Augier explains. “We hope that’s a theoretical scenario, but we can’t be sure. Should it happen, the individual would take every precaution to avoid being noticed.” Not to mention the energy required to power the computers needed for the blockchain system to work. www.edureka.co/blockchain-training Blockchain Certification Training

41. Blockchain: General Interview Questions 17. Name the common type of Network systems that are extensively being used in various applications? www.edureka.co/blockchain-training Blockchain Certification Training

42. Blockchain: General Interview Questions 17. Name the common type of Network systems that are extensively being used in various applications? www.edureka.co/blockchain-training Blockchain Certification Training

43. Blockchain: General Interview Questions 18. How is a blockchain ledger different from an ordinary one? www.edureka.co/blockchain-training Blockchain Certification Training

44. Blockchain: General Interview Questions 18. How is a blockchain ledger different from an ordinary one? Blockchain Ledger Ordinary Ledger Same copy of the ledger exist in the entire system The ledger may or may not be the same in the system The chances of error are less The chances of error are more Only read and create option exists. Anything once written cannot be altered You can perform all CRUD operations in such ledgers www.edureka.co/blockchain-training Blockchain Certification Training

45. Blockchain: General Interview Questions 19. What do you mean by mining? www.edureka.co/blockchain-training Blockchain Certification Training

46. Blockchain: General Interview Questions 19. What do you mean by mining? Mining is the process of adding transaction records to Bitcoin's public ledger of past transactions ➢ Miners are special Nodes which hold the copy of the ledger and verifies the transactions happening in the network ➢ Using state of the art cryptographic algorithm, miners validates the transactions across the network www.edureka.co/blockchain-training Blockchain Certification Training

47. Blockchain: General Interview Questions 20. A distributed digital ledger is used for recording transaction in Blockchain. What does the system rely on? www.edureka.co/blockchain-training Blockchain Certification Training

48. Blockchain: General Interview Questions 20. A distributed digital ledger is used for recording transaction in Blockchain. What does the system rely on? The system relies on the nodes of the network. The nodes in the blockchain network are responsible for the security and smooth running of the system. www.edureka.co/blockchain-training Blockchain Certification Training

49. Blockchain: General Interview Questions 21. Can You explain the components of Blockchain Ecosystem? www.edureka.co/blockchain-training Blockchain Certification Training

50. Blockchain: General Interview Questions 21. Can You explain the components of Blockchain Ecosystem? Node Application Each Node have to install and run a computer application definitive to the ecosystem they wish to participate in. Example- In bitcoin ecosystem, each computer must be running the bitcoin wallet Shared Ledger A data structure(Ledger) is managed inside the node application. Contents for the ecosystem can be viewed, once the node application is in running state Consensus Algorithm Implemented as part of the node application. Provides the rule for how the ecosystem will arrive at a single view of the ledger Virtual Machine (Smart Contract Functionality) An abstraction of a machine operated with instructions and Implemented as part of the node application that every participant in the ecosystem runs www.edureka.co/blockchain-training Blockchain Certification Training