20+ Blockchain Interview Questions and Answers in 2024

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Imagine you have your Blockchain Interview today. It is your first interview. Maybe you have given it already but are not satisfied with your performance. The question is, are you organized? Would you be able to answer the questions put forth to you? Are you equipped to answer any question and explain the concepts of Blockchain Technology? This blog will give you an idea of the what and how of the Interview questions and answers. Let us look at the top 20 Blockchain Interview questions and answers. These are the 30 most frequently asked questions and hence rank as the top 30 interview questions.

Let us understand first what is Blockchain Course Technology. It is a system of recording information. The information is recorded in such a way that makes it difficult to change once recorded. It is then impossible to hack or cheat into the system.

For our basic understanding, a blockchain is a digital ledger of transactions. The ledger is distributed across the entire network of computer systems on the Blockchain. Each block in the chain has several transactions. A record of every new transaction gets added to every participant ledger.

This decentralized database is managed by a platform with its cryptocurrency called Ether or Ethereum. This decentralized database that is managed by multiple participants is known as Distributed Ledger Technology or DLT.

Here are the 30 top interview questions asked in every Blockchain interview. These questions and the answers will build confidence and help you crack that interview.

Q1. What is Blockchain as per your knowledge?

Ans: Blockchain technology was invented with the invention of Bitcoin. It is a trusted approach that a lot of companies use in the present scenario. As everything is secure, and because it is an open-source approach, it can be easily trusted in the long run.

Q2. Are you aware of Distributed Ledger Technology?

Ans: The decentralized database that is managed by multiple participants is known as Distributed Ledger Technology or the DLT. A record of every new transaction gets added to every participant’s ledger.

Q3. What is Bitcoin?

Ans: Bitcoin is a cryptocurrency. Blockchain technology was invented with Bitcoin. Cryptocurrency is a medium of monetary exchange. It uses encryption techniques. This verifies the transfer of funds.

Q4. Can you explain the types of Blockchain?

Ans: There are four types of Blockchains.

Public: This is the type where anywhere can join and participate
Private: In this type, the organization governs and decides who is allowed to participate
Consortium: Different organizations can use and share the responsibilities to maintain the information, but these are pre-selected
Permissioned: In this type, the companies need to obtain invitations and permission to join and participate in the network

Q5. Are you aware of Ethereum?

Ans: Ethereum is a platform with its cryptocurrency called Ether or Ethereum. Solidity is their programming language. Ethereum is a decentralized public ledger that is used for verifying and recording transactions. The network users create, publish, monetize, and use applications on the platform. They use Ether cryptocurrency as payment.

Q6. What according to you, is the difference between Bitcoin and Ethereum?

Ans: Bitcoin is based on Digital Currency whereas, Ethereum is based on Smart Contracts. The founder of Bitcoin Blockchain is Satoshi Nakamoto, on the other hand, the founder of Ethereum is Vitalik Buterin. The release method is different. One is Genesis Block Mined and the other is Presale. The Cryptocurrency used is different. Bitcoin Blockchain uses Bitcoin and the other uses Ether. Bitcoin uses SHA-256 as its Algorithm, whereas, Ethereum uses Ethash. Furthermore, Bitcoin has a Block time of 10 minutes, and Ethereum has a maximum of 14 seconds.

Q7. Do you think Blockchain is a trusted approach?

Ans: Yes, I think that Blockchain is a trusted approach.

First, it is compatible with other business applications.

Second, it is secured. It is meant for online transactions, and due to this, the developers have paid special attention to its security.

Third, it can be easily considered, no matter what type of business.

Q8. What are the main elements of a Blockchain?

Ans: The key elements of Blockchain are

Distributed Ledger Technology: All participants have access to the distributed ledger and its record of transactions
Immutable records: Once recorded to the shared ledger, the participants cannot change a transaction
Smart Contracts: A set of rules called a smart contract is stored on the Blockchain to speed the transaction, and the transactions are executed automatically.

Q9. What do you think are the key features of Blockchain?

Ans: The main key features of Blockchain are

Decentralized Systems
It has enhanced security
Distributed ledgers
Quick
Safe and secure
It cannot be corrupted

Q10. What do you understand by blocks in Blockchain technology?

Ans: Blockchain consists of a list of records that get stored in blocks. These blocks are then linked with other blocks, and they create a chain called Blockchain.

Q11. What are Block Identifiers?

Ans: Blocks are identified by the block header and the block height. These are differentiated into the head of the block, which is the block header and block body.

Q12. In a Blockchain, can you remove one or more blocks from the networks?

Ans: Yes, With the help of default options and filters, this can easily be done without taking a lot of effort.

Q13. What is a ledger in a Blockchain?

Ans: A ledger is a database of the accounts maintained in a summarized and classified form. This helps organizations to generate their financial information and statements.

Q14. What are the common types of ledgers that can be considered by the users?

Ans: There are three types of ledgers that can be considered

Centralized Network
Decentralized Network
Distributed Network

Q15. Can You explain the three types of ledgers?

Ans: In a centralized Network the all the data is sent and received by a central Node. Any changes can only be made by this Node. Node is any computer that is connected to the Network and helps to run the Blockchain.

Distributed Ledger is a database where there are multiple users and multiple Nodes to control the database.
A decentralized Ledger is similar to Distributed Ledger. They have distributed Networks of Centralized ledgers.

Q16. Are you aware of the security of a block?

Ans: 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 will result in a change in the hash identifier of the block. It is a very secure network.

Q17. What are Merkle trees?

Ans: Merkle Tree is a data structure in cryptography. Each leaf node is a hash of a block of data, and each non-leaf node is a hash of its child nodes. It is also known as a hash tree.

Q18. What is the Importance of Merkle trees in Blockchains?

Ans: The benefit of using the Merkle tree in the blockchain is that we do not need to download every transaction and every block. If someone needs to verify a specific transaction, just downloading a part that contains this transaction is significant. We check the hashes which are going up the branch relevant to my transaction.

Q19. Can you explain the type of records that can be kept in a Blockchain?

Ans: The types of records that are kept on the Blockchains are:

Medical transactions
Identity management
Business transactions
Management activities
Transaction processing

Q20. In the distributed digital ledger, What does the system rely on when it is used for recording transactions?

Ans: When it is used for recording transactions, the system relies on the network servicing protocol and the nodes of the network.

Q21. Can you explain Blockchain Ecosystem

Ans: Blockchain is very effective when used to automate cross-enterprise workflows. This enables business processes and the sharing of data across enterprise boundaries. Doing this effectively requires an ecosystem with an agreed-upon structure defining the roles and behaviors of participants.

Q22. Can you name some popular platforms for developing Blockchain applications?

Ans: After Bitcoin, various platforms were initiated. Ethereum came right after the evolution of Bitcoins and is one of the popular platforms for building Blockchain-based applications. There is a Hyperledger community for enterprise-based solutions. There are other widely used platforms like Qtum, IOTA, and EOS.

Q23. What are the benefits of Blockchain?

Ans: The benefits of Blockchain are

It is extremely efficient
Is cost-saving
A very secure system
Immutability
Has better transparency

Q24. Are you aware of Double Spending?

Ans: Double Spending is a condition when one digital token is spent multiple times. This leads to inflation and the organizations have to bear huge losses. It simply means spending the money twice. Generally, this doesn’t happen in physical money. Once you pay the physical money, you cannot spend it again. This may happen in online transactions.

Q25. Can the Blockchain system avoid Double Spending?

Ans: Yes. The system helps to prevent double-spending. Before the actual transaction is written to the ledger it is confirmed by multiple parties. . The system helps to avoid double-spending by timestamping groups of transactions and broadcasting them to all the nodes in the network. As transactions are time-stamped on the blockchain, they are irreversible.

Q26. Can you explain, what type of records can be kept in a Blockchain?

Ans: Any record can be kept in Blockchain. There is no restriction. Keeping records of any type in the Blockchain is allowed. Due to high-level security, industries are using Blockchain for securing all types of records.

Q27. Please explain, how is a blockchain ledger different from an ordinary ledger?

Ans: The Blockchain is a digital ledger that can be decentralized easily. The chances of error in this approach are less than that of an ordinary ledger. An ordinary ledger is updated manually while the Blockchain performs all its tasks automatically.

Q28. Tell me, is it possible to remove one or more blocks from the networks?

Ans: Yes, there are times when a only specific portion of this online ledger is to be used. This can easily be done without making a lot of effort with the help of default options and filters.

Q29. Are you aware of some of the widely used cryptographic algorithms?

Ans: There are 5 widely used cryptographic algorithms, namely

Triple DES: Triple-DES uses three individual keys with 56 bits each. The total length adds up to 168 bits
RSA Security: RSA Security is a public-key encryption algorithm. It is the standard for encrypting data sent over the internet.
Blowfish: Blowfish is designed to replace DES. This symmetric cipher splits messages into blocks of 64 bits and encrypts them. Blowfish is known for its tremendous speed and effectiveness.
Twofish: Twofish is the fastest and is ideal for use in hardware and software environments. It is freely available to anyone who wants to use it.
AES: The Advanced Encryption Standard is the algorithm trusted by numerous organizations. AES is highly efficient in 128-bit form, AES also uses keys of 192 and 256 bits for heavy-duty encryption purposes.

Q30. What challenges does information leak impose on an organization?

Ans: An information leak can harm the reputation of an organization. It can be the reason for an organization to bear huge losses. Many organizations fail to implement security protocols, and as a result, lose the trust of their customers. The profits of any organization can rapidly reduce if no attention is paid to online transaction security.

Want to Get Trained?

These are the top 30 Blockchain Interview questions and answers. Knowing these questions, and being prepared with the answers to such questions will always be helpful in your next interview. Need to know about the best Blockchain course for your preparation. Want to get trained? Looking for the best institute for your training? Let us see the best Blockchain course offered. The course is offered by Henry Harvin Education.

Henry Harvin Education: Blockchain Certification Training Course

Henry Harvin is one of the leading careers and competency development organizations. The Blockchain course by Henry Harvin gives an overview of Bitcoin, Ethereum, Hyperledger, and Multichain platforms. You will learn to utilize various tools like Truffle, Ganache, Geth, and Meta Mask to build Blockchain applications. In this certification training, you will learn how to set up a private blockchain network using Hyperledger Composer and deploy smart contracts on Ethereum.

The Blockchain course duration

32 hours of training by instructors
Certification program
24 hours of Bootcamps for the next 12 months
You can attend unlimited batches for the next 1 year from the date of enrollment

Trainers

Trainers at Henry Harvin are the most respected industry experts. They Have been invited for more than 100 keynote classes for Blockchain Course Certification Trainings. They are currently empaneled as domain experts with Henry Harvin Blockchain Course Academy.

Course Curriculum

The Course Curriculum includes

Introduction to Bitcoin
Cryptography in Blockchain
Cryptocurrency

Henry Harvin offers two Complimentary Modules

Soft Skills development
Resume Writing

Certification

A globally acclaimed testimonial certification after the training. Certified Blockchain Practitioner (CBP) revamps your achievements as an Expert. Use it as a symbol of expertise with your name.

Benefits of Learning the Blockchain Course with Henry Harvin

Become an expert in the verification of data
Learn to keep the data ledgers secure with the use of cryptography
Receive high salaries and understand the process of how all the transactions go through maximum verification
Learn how to recover data if lost and become a part of the Blockchain Hyperledger community
Understand how the transactions are put in chronological order and how they are absolutely transparent to the individuals who have the authorization
Learn how the ledger is distributed across all the nodes in the Blockchain.
The industry-designed Blockchain Certification Training course with Henry Harvin can help you master all these technologies

Gold Membership Benefits of Blockchain Academy

Henry Harvin offers Gold Membership which provides the below-mentioned facilities to its members.

E-Learning Access: Get access to all recorded videos, games, projects, and case studies
Monthly Bootcamp Sessions: Brush up your concepts with regular Bootcamp sessions held every month
Job Opportunities and Internship: CBP graduates get 100% placement assistance and internship opportunities with Henry Harvin or partner firms.
Guaranteed Interview Support: Get Support in facing and clearing the interview

Other related courses offered by Henry Harvin are

Basic details about Bitcoin and Blockchain

Let us know more about Bitcoin and Blockchain, to begin with. Bitcoin is a digital currency created in January 2009. Bitcoin offers a lower transaction fee than traditional online payment and is operated by a decentralized authority. Bitcoin is a type of cryptocurrency.

There is no physical bitcoin. There are only balances kept on a public ledger and everyone has transparent access. All the transactions are verified. Bitcoin is created, distributed, and stored with the use of a decentralized ledger system, known as a Blockchain. Bitcoin has inspired other cryptocurrencies.

A Blockchain is a collection of blocks. In each block, there is a collection of transactions. All the computers running the blockchain have the same list of blocks and transactions, they can transparently see these new blocks being filled with new bitcoin transactions, no one can cheat the system.

The difference between Bitcoin and Blockchain

We are making a mistake if we say Bitcoin and Blockchain are the same. Creating cryptocurrencies is one of the applications of Blockchain technology. There are numerous applications that are being developed on the basis of blockchain technology.

In simple words, Blockchain can be described as a data structure that holds transactional records. It ensures security, transparency, and decentralization. Hence, It can be thought of as a chain of records stored in the forms of blocks. They are not controlled by any single authority.

Finally, a Blockchain is a distributed ledger that is completely open to anyone and everyone on the network. Once a piece of information is stored on a blockchain, it is extremely difficult to change it.

Conclusion

To summarize, I hope this makes your concepts clear. Use the top 30 Blockchain interview questions and answers to your best. You may know all the concepts, however, the best thing to get through an interview is your first impression. In addition to all the above, a small tip, reach the interview venue on time, be confident and answer what is asked. So, All the Best!

FAQs

Ques 1. What is Blockchain?

Ans: A blockchain is a collection of blocks, and in each block, there is a collection of transactions.

Ques 2. What is Bitcoin?

Ans: Bitcoin is a digital currency that was created in January 2009.

Ques 3. Is Blockchain secure?

Ans: Blockchain is secure and as a result, used by many organizations.

Ques 4. Are Bitcoin and Blockchain the same?

Ans: To begin with, Bitcoin is a cryptocurrency, and creating cryptocurrencies is one of the applications of Blockchain technology.

Ques 5. What is Double Spending?

Ans: Double Spending is a condition when one digital token is spent multiple times. This does not happen with physical currency.

Ques 6. What are Merkle trees?

Ans: Merkle Tree is a data structure in cryptography.

Ques 7. What are the key features of Blockchain?

Ans: Key features, for instance, are decentralized systems, enhanced security, distributed ledgers, quick, safe and secure.

Ques 8. What is a ledger in a Blockchain?

Ans: A ledger is a database of all accounts maintained in a summarized and classified form.

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