Blockchain Interview Questions And Answers Pdf

1. What is Blockchain Technology?
The blockchain is an incorruptible digital ledger of economic transactions that can be programmed to record not just financial transactions but virtually everything of value.

2. Why is Blockchain a trustworthy approach?
Blockchain can be trustworthy thanks to such a large amount of reasons.

Its compatibility with different business applications thanks to its open-source nature.

Blockchain security. Because it was meant for online transactions, the developers have paid special attention to maintaining the pace once it involves its security. It extremely doesn’t matter what style of business one owns, Blockchain will simply be thought of.

3. What is encryption? What is its role in Blockchain?
Data security always matters. Encryption is an approach that helps organizations to keep their data secure.cryptography-top blockchain interview questions-edurekaThe 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.

4. 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

5. What type of records can be kept in Blockchain? Is there any restriction on the same?
There is no restriction of keeping records of any type in the Blockchain approach. Presently, a lot of organizations all over the world are using this approach and the fact is records of medical transactions, events related to organizations, management activities, transaction processing, identity management, as well as documentation are the common type of records that can be kept on them. It must be noted that the record-keeping is not just limited to these applications only. 

6. What are the various approaches employed in attacking the RSA algorithm?

There square measure different approaches employed in assaultive the RSA algorithm:

Brute force: It involves all potential secret keys

Mathematical attacks: In mathematical attack, we tend to square measure mistreatment different techniques, that is analogous in the effort to issue the merchandise of 2 primes

7. Name the common sort of ledgers which will be thought of by users in Blockchain?

These are:

  • Centralized Distribution
  • Decentralized distribution
  • Distributed network
  • Follow the link to know more about Ledger

8. What are smart contracts in Blockchain?
Blockchain is used for storing smart contracts because of the permanent record-holding capacity and the security it offers to the network users. In Smart contract data, it is impossible to lose the information stored in the blocks and they are encrypted on a shared ledger. Smart contracts allow the performance of credible transactions without third parties. 

9. How does a block is recognized in the Blockchain approach?
Every block in this online ledger consists of a hash pointer that acts as a link to the block which is before it, transaction data and a stamp of time.

10. What do you understand by Blockchain?
The blockchain is a redistributed distributed database of immutable records. The technology was discovered with the invention of Bitcoins (the 1st cryptocurrency). It’s a trusty approach and there are heaps of firms within the present situation that are using it. As everything is secure, and since it’s Associate in Nursing open supply approach, it will simply be sure in the long run.

11. Name the 2 kinds of records that are present within the Blockchain Database?
These records are block records and transactional records. Each of these records will simply be accessed, and also the neatest thing is, it’s doable to integrate them while not following the complicated algorithms.

12. Are there any network-specific conditions for using Blockchain technology in an organization?
There is no specific condition on 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. 

13. Name some widespread platforms for developing blockchain applications?
After the event of bitcoin, numerous blockchain platforms started arising. Ethereum came right once the evolution of Bitcoins and is one in all the favored public platforms for building Blockchain primarily based applications.

Then there’s a Hyperledger community for building enterprise-based solutions. Also, Qtum, IOTA, EOS are a number of the widely used platforms for building Blockchain.

Blockchain Decentralized Applications (DAPPS): Ethereum

14. What type of records is kept in a Blockchain? Is there any restriction on the same?
There is no restriction on keeping records of any sort within the Blockchain approach. Industries are using Blockchain for securing all kinds of records.

The common kinds of records (to name a few) which will be unbroken on the Blockchains are:

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

15. What are the blockchain requirements?
Blockchain is a truly disruptive technology that can transform business networks. We also believe that this innovation has to happen in the open, collaborating with other technology companies and industries. To this end, IBM continues to contribute code to the Hyperledger Project.

From IBM’s perspective, industrial-grade blockchain technologies have the following characteristics:

A shared, permissioned ledger is the append-only system of record (SOR) and a single source of truth. It is visible to all participating members of the business network.
A consensus protocol agreed to by all participating members of the business network ensures that the ledger is updated only with network-verified transactions.
Cryptography ensures tamper-proof security, authentication, and integrity of transactions.
Smart contracts encapsulate participant terms of agreements for the business that takes place on the network; they are stored on the validating nodes in the blockchain and triggered by transactions. 
In addition to these attributes, enterprise blockchain technology needs to meet key industry requirements such as performance, verified identifies, and private and confidential transactions. Hyperledger Fabric has been architected to meet these needs. It is also designed with a pluggable consensus model, allowing businesses to select an optimal algorithm for their networks.

16. How is a block recognized within the Blockchain approach?
Every block during this online ledger essentially consists of a hash pointer that acts as a link to the block that is before it, transaction knowledge and a stamp of time

17. State difference between proof of stake and proof of work?

Proof of Work

  • The possibility of Mining a Block depends upon the amount of work a miner does
  • Takes more energy than a proof of stake

Proof of Stake

  • Stakeholder Validate new block by but utilizing their share of coin on the network
  • The first example of proof of stake is Peercoin

18. What exactly does one comprehend the security of a block?
Well, a block or the complete blockchain is protected by a powerful cryptographic hash algorithm. Every block includes a distinctive hash pointer. Any modification within the block constituents will lead to the modification within the hash identifier of the block. Therefore, it offers a wonderful level of security. Thus, one needs to not worry regarding the protection additionally because of the security of knowing that’s a gift in an exceedingly block.

19. How is a blockchain ledger different from a standard one?
The first and of course the prime distinction is Blockchain is a digital ledger that will be decentralized simply. The probabilities of error during this approach are way under that in a standard ledger. An ordinary ledger is what that’s ready by hands or by human efforts whereas the Blockchain performs all its tasks mechanically. You simply have to be compelled to assemble it in an exceedingly correct manner and by following all the rules.

20. What is Secret Sharing in Blockchain technology?
Secret sharing offers security advantage in Blockchain technology, it is a method that is used to divide your personal or secret information into different units & sends them to the users of your network. The original information can only be shared when the member to whom a share of the secret is allocated approves to combine them with other network users.

21. Explain the importance of blind signature and the way it’s useful?
It is a type of digital signature within which the content of a message is disguised (blinded) before it’s signed. The ensuing blind signature may be publically verified against the first, unblinded message within the manner of a daily digital signature.

Blind signatures are generally used in privacy-related protocols where the signer and message author are different parties. Examples include cryptographic election systems and digital money schemes.

22. How is a blockchain ledger different from an ordinary one?
The first and the prime difference is Blockchain is a digital ledger that can be decentralized very easily. The chances of error in this approach are far less than that in an ordinary ledger. An ordinary ledger is what is prepared by hands or by human efforts while the Blockchain performs all its tasks automatically. You just need to configure it in a proper manner and by following all the guidelines.

23. What type of records can be kept in a Blockchain? Is there any restriction on the 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

24. Why Blockchain is a trusted model of the transaction?
Blockchain is an open source but due to its high security and encryption, it is considered as a trusted mode of transaction. The developers paid special attention in keeping up the pace when it comes to its security, once a data is made an entry, it cannot be deleted in the blockchain.

25. Why Blockchain is a trusted approach?
Blockchain can be trusted due to so many reasons. The very first one is its compatibility with other business applications due to its open-source nature. Second is 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 doesn’t matter what type of business one owns, Blockchain can easily be considered.

26. Can you make a case for what square measure off-chain transactions?
Off-chain dealing is that the movement of value outside of the blockchain. while associate on-chain dealings – usually observed as merely ‘a transaction’ – modifies the blockchain associated depends on the blockchain to see its validity an off-chain transaction depends on alternative ways to record and validate the transaction. 

27. What challenges information leak can impose on an organization?
Information leaks can cut down the reputation of an organization up to an excellent extent. In addition to this, it can be the reason for an organization bearing huge losses. Many organizations that 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.

28. What are the advantages of Blockchain that you simply know?

There are plenty of benefits for Blockchain:

  • Settlement in real-time
  • Cost-saving
  • Immutability
  • Security
  • User Pseudonymity

29. What are the Merkle trees? How vital are Merkle trees in Blockchains?
Merkle Tree additionally called ‘hash tree’ is a data structure in cryptography during which every leaf node could be a hash of a block of knowledge, and every non-leaf node could be a hash of its kid nodes.

if somebody has to verify the existence of selected dealing in an exceedingly block, then he doesn’t need to transfer the complete block. Downloading a collection of a branch of this tree that contains these dealings is enough. We tend to check the hashes we are simply rising the branch (relevant to my transaction). If these hashes consider sensible, then we all know that these specific dealings exist during this block.

30. What is a 51% attack and how to prevent it?
51% Attack occurs when a group of miners who has > 50% of the Network Hash Rate could manipulate the network with the New transactions or able to reverse the already take placed confirmed transactions that and kind of doing Double spend. The probability of the occurrence of such an attack is very less. Running mining pools can prevent 51 attacks.

31. 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.

32. How you will handle the risk management when it comes to securing the transactions records?
It is a process of finding the threats and all the vulnerabilities to the financial records of an organization. The best thing that can be done against this approach is to take the right counter measures against them immediately. Another approach is to pay attention to a back-up plan. Based on the value of information, more approaches such as buying new risk management software can simply be considered. The prime risk of information is from black-hat hackers.

33. What do you mean by blocks within the Blockchain Technology?
Blockchain consists of a list of records. Such records are kept in blocks. These blocks are successively linked with different blocks and therefore represent a sequence known as Blockchain.

34. What do you know about Merkle trees in Blockchain?
Merkle Tree is also called a ‘hash tree’. It is like a data structure in cryptography where each leaf node is like a hash of a block of data, and each non-leaf node is like a hash of its child nodes. It is a “light client” which can only download the chain of block headers for verifying transactions.

35. What are the key principles in Blockchain that help eliminate the security threats that need to be followed?

Yes, there are a few principles that need to be followed concerning time. They are:

2.Securing applications
3. Securing testing and similar approaches
4. Database security
5. Continuity planning
6. Digital workforce training

36. What is Consensus in Blockchain?
The consensus provides the technical infrastructure layer for blockchains. This makes it one of the most critical components when assessing real-world use cases. The consensus is key, because, without a central authority, the participants have to agree on the rules and how to apply them

37. 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.

Furthermore, the blockchain, because of its open-source nature, is more versatile and programmable than central banking ledgers. If programmers need new functionality on the blockchain, they can simply innovate on top of already existing software through consensus. This is difficult for central banks because of all of their regulations and central points of failure.

38. 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.

Blockchain prevents double-spending by confirming a transaction by multiple parties before the actual transaction is written to the ledger. It’s no exaggeration to say that the entirety of bitcoin’s system of Blockchain, mining, proof of work, difficulty etc, exists to produce this history of transactions that is computationally impractical to modify.

39. 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.

40. What is Secret Sharing? Will it have any benefit in Blockchain technology?
It is a widely known indisputable fact that security matters tons in digital transactions. Secret sharing is an associate approach meant for the same. In Blockchain technology it’s an associate approach that divides secret or personal data into totally different units and sent them to the users on the network. 

The original data will solely be mixd once a participant to whom a share of the key is allotted conform to combine them at the side of others. Their square measure many security-related edges it offers in Blockchain technology.

41. How are transactions and blocks encrypted in the Bitcoin implementation?
Bitcoin blocks are public and they are not encrypted in any way. Block hash only prevents modifications and it also guarantees the data integrity in the Block content. The block content in Bitcoin is processed using a special hash function called “SHA256” and the resulting value is stored in Blockchain.

42. 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 (channel is a link between the sender and a receiver). The work done to convert the information at both the sender and receiver end is generally regarded as information processing. The biggest challenge to information processing is securing it during that time. Another challenge is processing bulk information that can impose a limit on performance.

43. Name organizations that can use Blockchain technology?
There is no strict upper limit on the category of business that 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.

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