Blockchain Interview Question ?

Advantages:

Challenges of Block-chain:

  • Higher costs — as Nodes seek higher rewards for completing Transactions in a Supply and Demand scenario
  • Slower transactions — as Nodes prioritise Transactions with higher rewards, backlogs of transactions build up
  • Smaller ledger — Not every Node can carry a full copy of the Blockchain, potentially affecting immutability, consensus etc.
  • More centralised — There is a high barrier to entry to become a Node, encouraging a larger amount of centralisation in the Network, with bigger players able to take more control.

Q 4. Why is Blockchain a trusted approach?

Blockchain can be trusted due to so many reasons. Its compatibility with other business applications due to its open-source nature. Its security. As it was meant for online transactions, the developers have paid special attention to keeping up the pace when it comes to its security. It really doesn’t matter what type of business one owns, Blockchain can easily be considered.

Q 5. Name the two types of records that are present in the blockchain database?

These records are block records and transactional records. Both these records can easily be accessed, and the best thing is, it is possible to integrate them with each other without following the complex algorithms.

Q 6. Blockchain is a distributed database. How does it differ from traditional databases?

Properties

Q 7. What are the properties of Blockchain?

There are four key features of blockchain:

  • Decentralized Systems
  • Distributed ledger
  • Safer & Secure Ecosystem
  • Minting

Q 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.

Q 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.

Q 10. How a block does 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.

Q 11. Is it possible to modify the data once it is written in a block?

No, it’s not possible to do so. In case any modification is required, the organization simply has to erase the information from all other blocks too. It is because of no other reason than this, data must be given the extreme care of while using this approach.

Q 12. What are Block Identifiers?

In Blockchain, blocks can be identified by the block header hash and the block height.

Q 13. Is it possible in Blockchain to remove one or more block from the networks?

Yes, it can be done. There are times when only a specific portion of this online ledger is to be considered. With the help of default options and filters, this can easily be done without making a lot of efforts.

Q 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. Therefore, it offers an excellent level of security. Thus, one needs not to worry about the safety as well as the security of data that is present in a block.

Q 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.

Q 16. What is a ledger? Is Blockchain an incorruptible ledger?

Blockchain is considered incorruptible. Any ill-intentioned individual acting alone is powerless. “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.

Q 17. Name the common type of ledgers that can be considered by users in Blockchain?

These are:

  • Records of medical transactions
  • Identity management
  • Transaction processing
  • Business transactions,
  • Management activities
  • Documentation

Q 22. State difference between proof-of-work & proof-of-stake?

Q 23. Name some popular platforms for developing blockchain applications

After the development of bitcoin, various blockchain platforms started coming up. Ethereum came right after the evolution of Bitcoins, and is one of the popular public platforms for building Blockchain based applications.

Q 24. What is Double Spending? Is it possible to double spend in a Blockchain system?

It’s a condition when one digital token is spent multiple times because the token generally consists of a digital file that can easily be cloned. It simply leads to inflation and organizations must bear a huge loss. One of the primary aims of Blockchain technology is to eliminate this approach up to the possible extent.

Q 25. What are the benefits of Blockchain that you know?

Advanced Blockchain Interview Questions

Q 1. Can you tell me some of the widely used cryptographic algorithms?

Q 2. Tell me more about RSA algorithm? How secure is this algorithm?

  • Brute force: It involves all possible secret keys
  • Mathematical attacks: In mathematical attack, we are using different techniques, which is similar in effort to factor the product of two primes

Q 3. Explain the significance of blind signature and how it is useful?

It is a form of digital signature in which the content of a message is disguised (blinded) before it is signed. The resulting blind signature can be publicly verified against the original, unblinded message in the manner of a regular digital signature.

Q 4. What is Secret Sharing? Does it have any benefit in Blockchain technology?

It is a well-known fact that security matters a lot in digital transactions. Secret sharing is an approach meant for same. In Blockchain technology it is an approach that divides secret or personal information into different units and sent them to the users on the network.

Q 5. Can you explain what off-chain transactions are?

An off-chain transaction is the movement of value outside of the blockchain. While an on-chain transaction — usually referred to as simply ‘a transaction’ — modifies the blockchain and depends on the blockchain to determine its validity an off-chain transaction relies on other methods to record and validate the transaction.

Q 6. What exactly do you know about executive accounting? Does Blockchain support the same?

Executive accounting is nothing but a special type of accounting which is designed exclusively for a business that offers services to the people. There is no strict upper limit on services and a business can manage any through the executive accounting. Blockchain has algorithms that are specially meant to handle executive accounting. In fact, it cut down many problems that are associated with the same.

Q 7. What are the threats to the information you are familiar with?

There are lots of threats to information in the present scenario. Due to increase in online transactions over the internet, many hackers have become active and are adopting new approaches to hack information and servers that contain financial information.

Q 8. How will you handle the risk management when it comes to securing the transactions records?

It is basically a process of finding the threats and all the vulnerabilities to the financial records of an organization. The best thing that can be done with this approach is to take the right countermeasures against them immediately.

Q 9. What is 51% attack?

51% Attack refers to a situation where a group of miners who hold more than 50% of the Network Hash Rate could manipulate with the New transactions (Stopping the transactions to proceed or gaining conformations) or able to reverse the transactions that were recently confirmed and kind of doing Double spend. It is Highly unlikely to be able to do that today but it is possible.

Q 10. What challenges information leak can impose on an organization?

An information leak can cut down the reputation of an organization up to an excellent extent. In addition to this, it can be the reason for organization bearing huge losses. Many organizations who fail to implement security protocols to keep their data secure have already lost the trust of their customers and are struggling very hard to get the same reputation again. The overall profits of any organization can reduce up to 80% if no attention is paid to the online transaction security.

Q 11. What is information processing according to you? What are the key challenges that are associated with it?

The information is often shared on a network. Before actually transmitting it over a network, it needs to be changed into formats that can fit the standards of the channels (the channel is a link between the sender and a receiver).

Q 12. Name organizations that can use Blockchain technology?

There is no strict upper limit on the category of business who can consider this approach. The fact is almost all the businesses are engaged in online or financial transactions that they need to make to run the processes smoothly. Large-scale corporations, financial institutions, private businesses, government departments and even defense organizations can trust this technology very easily.

Q 13. What are the core requirements for a Business Blockchain?

A business blockchain requires a shared ledger, smart contract functionality, privacy and trust.

Q 15. What is a security policy?

A security policy defines what exactly needs to be secured on a system. It bounds a network user under some core protocols that they all must agree and follow to enhance the overall security. When it comes to information or financial records of an organization, multiple security policies are implemented than just one.

Q 16. Is the Blockchain Different from Banking Ledgers?

Banks and accounting systems use ledgers to track and timestamp transactions. The difference is that the blockchain is completely decentralized and an open source. This means that people do not have to rely on or trust the central bank to keep track of the transactions. The peer-to-peer blockchain technology can keep track of all the transactions without the fear of having them erased or lost.

  • PBFT (Practical Byzantine Fault Tolerance)
  • Proof-of-work
  • Proof-of-stake
  • Delegated proof-of-stake
  • Proof-of-elapsed time
  • Different business needs
  • Different use cases
  • Also:
  • Cryptography/Strength of Algorithm
  • Regulation requirements
  • Implementation
  • Performance
  • Tokenization
  • Security
  • Privacy

Q 18. Is there any network specific conditions for using Blockchain technology in an organization?

There is no specific condition of using it. However, the network must be a peer-to-peer network under the concerned protocols. It validates the new block simply and helps organizations to keep up the pace in this matter without investing in third-party applications.

Q 19. Name the steps that are involved in the Blockchain project implementation?

Well, there are total six steps involved in this process and they are:

  1. Requirement identification
  2. Screen ideas consideration
  3. Project development for Blockchain
  4. Feasible study on the security
  5. Implementation
  6. Controlling and monitoring the project

Q 20. Explain a real-life use-case where Blockchain is being used?

Blockchain in Stock Market

  • Depositories and transfer agents are a single point of failure
  • Registration, transfer, distribution, scrutineering, courier fees
  • The more widely held, the higher the administration costs
  • Information asymmetry leads to market advantages
  • Forged securities still a concern
  • Counterparty risk is systemic

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