Blockchain is one of the fastest evolving technologies. And there are various possibilities available from various renowned companies around the globe. As a consequence, the candidate has the chance to advance in the Blockchain career as a Certified Blockchain Expert. With the demand for Blockchain advancing every day and new jobs initiating up in the area, it is noteworthy to know how one can plan for Blockchain interviews to get their dream job as a Certified Blockchain Expert. So, here we have placed the most commonly asked interview questions on Blockchain Technology to assist you to ace the next interview.
Can you explain what a blockchain is and how it works?
A blockchain is a decentralized, digital ledger that records transactions across a network of computers. It uses cryptography to secure and verify transactions, as well as to control the creation of new units of a particular cryptocurrency. Each block in a blockchain contains a number of transactions, and once a block is added to the blockchain it cannot be altered or deleted. This creates a permanent and tamper-proof record of all transactions on the network. The decentralized nature of a blockchain network means that it is not controlled by a single entity, making it more secure and transparent than traditional ledger systems. In order to add a block to the blockchain, the network must reach consensus on the validity of the transactions contained within it. This is typically achieved through a consensus algorithm, such as Proof of Work or Proof of Stake.
What are the key differences between public and private blockchain networks?
Public blockchain networks are open to anyone and can be freely joined by anyone. They are decentralized, meaning there is no single entity in control, and transactions are verified through a consensus mechanism. Examples of public blockchains include Bitcoin and Ethereum.
Private blockchain networks, on the other hand, are typically restricted to a set of participants, who are granted permission to join the network. They are typically centralized, meaning they are managed and controlled by a single entity. They are used by businesses and organizations to improve efficiency and security in their operations, and transactions on private blockchain networks are usually validated by a trusted group of participants.
One key difference between public and private blockchains is the level of transparency. Public blockchains are more transparent, as all transactions are publicly accessible. Private blockchains, on the other hand, have more control over the visibility of transactions, as access is restricted to a select group of participants.
Another key difference is the level of security. Public blockchains are generally considered more secure due to the decentralized nature of their consensus mechanism, while private blockchains can be vulnerable to tampering or hacking attempts by malicious actors with access to the network.
Finally, the performance of public and private blockchains can also differ significantly, with public blockchains often having slower transaction times and higher fees, while private blockchains can offer faster transaction times and lower fees.
How have you used blockchain technology to enhance security and trust in applications and systems?
Blockchain technology has the potential to enhance security and trust in applications and systems by providing a secure, transparent, and decentralized ledger of transactions. The use of cryptography and consensus algorithms such as Proof of Work (PoW) or Proof of Stake (PoS) ensure the integrity and immutability of the data stored on the blockchain. By leveraging blockchain, applications can eliminate the need for intermediaries and reduce the risk of data tampering, hacking, and fraud.
In addition, blockchain enables the creation of smart contracts, which are self-executing contracts with the terms of the agreement directly written into code. Smart contracts can automate the process of executing contracts and can enforce the terms of the agreement, further enhancing security and trust in applications and systems.
Overall, the use of blockchain technology has the potential to provide enhanced security, trust, and transparency in various applications and systems, including finance, healthcare, supply chain management, and many others.
Can you describe your experience with popular blockchain platforms such as Ethereum, Hyperledger, and Bitcoin?
Ethereum is a decentralized, open-source platform that enables the creation and deployment of smart contracts and decentralized applications (dapps). It supports a Turing-complete programming language and provides a high level of security, privacy, and transparency.
Hyperledger is a collection of open-source blockchain and distributed ledger technologies. It provides a modular and scalable platform for developing, deploying, and running blockchain-based applications in a variety of industries, such as supply chain, finance, and healthcare.
Bitcoin is a decentralized cryptocurrency and the first blockchain-based digital asset. It uses a consensus algorithm known as Proof of Work (PoW) to secure transactions and maintain the integrity of the network. Bitcoin is widely used as a means of payment and as a store of value.
Each platform has its own strengths and weaknesses, and the choice of which platform to use depends on the specific needs and requirements of the application being developed.
How have you used smart contracts in blockchain applications, and what are the key benefits of using smart contracts in blockchain?
Smart contracts in blockchain are self-executing computer programs that enforce the rules and regulations specified in the contract, and automatically trigger certain actions based on the predefined conditions. The use of smart contracts in blockchain allows for secure and transparent execution of transactions without the need for intermediaries.
I have used smart contracts in several blockchain projects to automate various business processes, such as supply chain management, asset management, and voting systems. One of the key benefits of using smart contracts in these projects is the ability to enforce and execute the terms of the contract without any human intervention, reducing the risk of fraud or manipulation. Additionally, smart contracts provide a tamper-proof record of all transactions and ensure that data is secure and transparent, providing greater accountability and trust.
Best practices for using smart contracts in blockchain include:
- Clearly defining the requirements and conditions of the contract
- Carefully testing the smart contract code to prevent errors and security vulnerabilities
- Monitoring the performance and security of the contract after deployment
- Regularly updating the contract to address any bugs or security vulnerabilities.
Can you explain how consensus algorithms such as Proof of Work (PoW) and Proof of Stake (PoS) work in a blockchain network?
Consensus algorithms are used in blockchain networks to validate transactions and maintain network security. There are several consensus algorithms, including Proof of Work (PoW) and Proof of Stake (PoS).
Proof of Work (PoW): In a PoW algorithm, network participants, called nodes or miners, compete to solve complex mathematical puzzles. The first miner to solve the puzzle is awarded the right to add a block of transactions to the blockchain and receive a reward. The solution to the puzzle, called a hash, is then distributed to other nodes for verification. Once a majority of nodes have verified the hash, the block is added to the blockchain. PoW algorithms are used in blockchains such as Bitcoin.
Proof of Stake (PoS): In a PoS algorithm, network participants are chosen to validate transactions and add blocks to the blockchain based on the amount of cryptocurrency they hold and are willing to “stake”. This creates an incentivized mechanism for participants to validate transactions and maintain the security of the network. Unlike PoW, PoS algorithms do not require intensive computational power, making them more energy-efficient. PoS algorithms are used in blockchains such as Ethereum and Cardano.
Both PoW and PoS algorithms play a crucial role in maintaining the security and reliability of a blockchain network by preventing malicious actors from controlling the network or tampering with the data stored on the blockchain.
How have you integrated blockchain with other technologies, such as IoT, AI, and cloud computing?
Integrating blockchain with other technologies such as IoT, AI, and cloud computing can enhance the capabilities of the blockchain-based applications and provide new opportunities.
For instance, integrating blockchain with IoT devices enables secure and transparent tracking of the data generated by IoT devices. Blockchain provides secure and tamper-proof storage of the data, while IoT devices provide real-time data collection.
Similarly, integrating blockchain with AI allows for creating decentralized AI applications that are transparent, secure, and trustworthy. This integration enables secure sharing and exchange of data for AI training and model development.
Additionally, integrating blockchain with cloud computing provides benefits such as enhanced security, scalability, and cost savings. Cloud computing can be used to host and scale the blockchain infrastructure, while blockchain provides secure and decentralized data storage.
Overall, the integration of blockchain with other technologies expands the capabilities of blockchain-based applications and provides new opportunities for creating secure, transparent, and decentralized applications.
Can you describe the process of developing and deploying a blockchain-based application, including the use of tools and platforms for development and testing?
The process of developing and deploying a blockchain-based application typically involves the following steps:
- Ideation and Requirements Gathering: The first step is to determine the problem statement and identify the requirements for the blockchain-based application.
- Architecture Design: Next, the architecture for the blockchain-based application is designed, taking into consideration the technical requirements, security, and scalability needs.
- Choosing a Blockchain Platform: Based on the requirements, the appropriate blockchain platform is selected. The most commonly used platforms are Ethereum, Hyperledger, and EOS.
- Development: The next step is to develop the smart contract, which is a self-executing contract that is stored on the blockchain and contains the rules and conditions for the transactions.
- Testing: The developed smart contract and the application are then tested to ensure that they are secure and free of bugs.
- Deployment: Once the testing is complete, the smart contract is deployed on the blockchain network.
- Maintenance and Upgrades: After deployment, the blockchain-based application must be maintained and upgraded as needed to ensure its continued performance and security.
Best practices for development and testing include using automated testing tools, conducting security audits, and using tools for version control and collaboration. Additionally, it is important to consider the network’s consensus mechanism, network security, and data privacy when developing and deploying blockchain-based applications.
How have you used blockchain to support data management, privacy, and compliance with regulatory requirements?
Blockchain can be used to support data management, privacy, and compliance with regulatory requirements in the following ways:
- Data Management: Blockchain provides an immutable and decentralized ledger, making it an ideal technology for securely storing and managing sensitive data. The data can be encrypted and stored on the blockchain, making it resistant to tampering or manipulation.
- Privacy: Blockchain enables the creation of private networks, where data is only visible to authorized participants. This makes it a useful tool for ensuring the privacy of sensitive data, such as personal health information or financial transactions.
- Compliance with Regulatory Requirements: Blockchain’s tamper-proof ledger can help organizations comply with regulations such as the General Data Protection Regulation (GDPR) by providing an auditable record of data access and usage. Additionally, blockchain smart contracts can be used to enforce compliance with regulatory requirements, such as those related to supply chain management or cross-border payments.
It is important to note that the use of blockchain in these industries is still in its early stages, and more work is needed to fully understand the potential impact and address any technical and regulatory challenges.
Can you explain the potential impact of blockchain on industries such as finance, healthcare, and supply chain management?
Blockchain has the potential to significantly disrupt and transform various industries, including finance, healthcare, and supply chain management.
In finance, blockchain can enable faster and more secure financial transactions, as well as reduce the costs associated with intermediaries.
Further, in healthcare, blockchain can improve data security and interoperability, enabling secure sharing of patient data across healthcare providers and reducing medical errors.
In supply chain management, blockchain can provide greater transparency and traceability of goods, enabling organizations to improve efficiency, reduce costs, and increase customer trust.
It is important to note that while the potential impact of blockchain on these industries is significant, it is still in the early stages of adoption and more work is needed to fully realize its benefits.
1. Define Public Blockchain.
A Public blockchain is a variety of blockchain that is “for the people, by the people, and of the people.” There is no in-charge it suggests anyone can understand, write, and review the blockchain. It is an open-source, shared, and decentralized public record so anyone can analyze anything on a public blockchain. They are deemed to be Permissionless blockchains.
2. Do you know Distributed Ledger Technology?
The decentralized database that is maintained by various participants is recognized as Distributed Ledger Technology or DLT. An account of all new transactions gets attached to each participant’s ledger.
3. Define Ethereum (ETH).
Ethereum is an open-source software program based on the Blockchain technology that allows developers to organize and expand decentralized purposes (i.e., applications that are not constrained by a separate entity). We may build a decentralized application in which the members are the ones who make the judgments.
4. Tell us some advantages of the Blockchain technology.
The principal perks of blockchain technology are:
- Immutability: There are various records generated and collected of a single block over the peer-to-peer interface so it is very hard to adjust something in the block.
- Security: The activities are very protected as it is based on cryptography.
- Transparency & Resiliency: As all the activities are collected over a distributed network so everyone can observe it, which makes blockchain translucent and resilient.
5. Describe a Blockchain Explore.
A blockchain explorer is a bit of software that extracts data from a blockchain utilizing an API and a blockchain node, then practices a database to create the data and grant it to the user in a searchable form.
6. Name some prominent applications of the blockchain in business.
Some Blockchain Applications are:
- Secure sharing of the medical data.
- NFT marketplaces.
- Cross-border payments.
- Music royalties tracking.
- Personal identity security.
- Supply chain and logistics monitoring.
- Real-time IoT operating systems.
7. Do you think Blockchain is a good approach?
Yes, I believe that Blockchain is a consigned approach.
- First, it is harmonious with other business applicability.
- Second, it is guaranteed. It is expected for online transactions, and due to this, the developers have contributed specific attention on its protection.
- Third, it can be commonly recognized, no matter what variety of the business.
8. Explain Merkel Tree.
Merkel Tree is a data construction that is practiced for establishing a block. It is in the application of a binary tree including cryptographic hashes of every block. It is structured likewise to a binary tree where every leaf node is a hash of a piece of transactional data and every non-leaf joint is a hash of its leaf node. The hash root or merkel root is the ultimate hash root of all the business hashes. It incorporates all the transactions that are holding all the non-leaf nodes.
9. Where do you think blockchain is stored?
The blockchain can be either saved as a flat record or as a database.
10. Define Hashing in Blockchain.
The means of making an data item of any portion designates an output item of a established length is attributed to as hashing in the blockchain. Take, for instance, the application of blockchain in cryptocurrencies, where activities of different lengths are managed through a provided hashing algorithm and all provide a fixed-length representation.
11. Name the principal elements of a block.
The major elements of a block are:
- A hash pointer to the ere block
- List of the transactions
12. Explain the Consensus and name the generally used consensus models.
Ans. A consensus is a comprehensive agreement which is practiced to confirm the transactions while accompanying a protocol. A consensus is essentially of 2 types –
- Proof of the work
- Proof of the stake
13. What do you think are Block Identifiers?
Ans. Blocks are recognized by the block height and the block header. These are distinguished into the head of the block, which is the block header and block body.
14. Is it possible to eliminate 1 or more blocks from the networks in the blockchain?
Yes, it is permissiblez. Sometimes, only a appropriate part of this online ledger requires to be recognized. By utilizing default filters and opportunities, we can eliminate the blocks.
15. What happens when we try to deploy a file with various contracts?
In Blockchain, extending a file with various contracts is not feasible. The compiler only expands the latest contract from the uploaded file and the outstanding contracts are ignored.
16. Name few popular platforms for creating the blockchain applications.
Some popular platforms for developing the blockchain are:
- Hyperledger Sawtooth
- R3 Corda
17. What are the general types of ledgers that are acknowledged by users in blockchain?
The general types of ledgers acknowledged by the users in the Blockchain are:
18. In what position blocks are linked in the blockchain?
All the blocks in blockchain are connected in backward order or every block links with its preceding block.
19. Can we change the data in a block?
No, it’s not permissible to change the data in a block. In situation any adjustment is required, we would have to delete the data from all other connected blocks too.
20. Are you acknowledged about the security of a block?
A block or the whole blockchain is guarded by a secure cryptographic hash algorithm. Every block has a different hash pointer. Any change in the block will occur in a difference in the hash identifier of the block. It is a very reliable network.
21. Is Blockchain an incorruptible ledger?
Yes, Blockchain is an honorable ledger. According to the inventor, the blockchain database cannot be tampered with.
22. Which cryptographic algorithm is practiced in the Blockchain?
Blockchain practices the SHA-256 Hashing Algorithm. The (NSA) National Security Agency in the USA originate the SHA-256 Hashing Algorithm.
23. Explain a Genesis Block.
The genesis block is the initial block in the Blockchain which is also called block 0. In Blockchain, it is the only block that doesn’t commit to its unfounded block. It describes the parameters of Blockchain.
24. Explain the DeFi technology.
Decentralized Finance can be designated as financial services applying smart contracts that don’t require any primary authority and use decentralized, distributed ledger technology, Blockchain. Most of the DeFi protocols are based on the Ethereum Blockchain network.
25. How can you define an off-chain transaction?
A transaction that takes position outside of the blockchain is called an off-chain performance. An on-chain transaction – often relegated to as simply “a transaction” – transforms the blockchain and relies on the blockchain to verify its legitimacy, while off-chain transaction documents and verifies the transaction utilizing other means.
26. Define the Merkle trees.
The Merkle tree is a primary element of blockchain technology. It’s a measurable data structure composed up of hashes of multiple data blocks that perform as a representation of all the businesses in a block.
27. What do you think is the Coinbase transaction?
A Coinbase transaction is the initial transaction in a block. It is a different type of bitcoin transaction that can be performed by a miner. The miners practice it to accumulate the block reward for their business and any other transaction charges accumulated by the miner are also conducted in this transaction.
28. Explain the kinds of consensus algorithms.
The most traditional consensus algorithms possible are recorded below:
- Proof-of-Capacity (PoC)
- Proof-of-Activity (PoA)
- Byzantine Fault Tolerance
- Proof-of-Capacity (PoC)
- Proof-of-Activity (PoA)
- Delegated Proof-of-Stake(DPoS)
- Delegated Proof-of-Stake(DPoS)
- Proof-of-Elapsed Time
- Unique Node Lists
- Unique Node Lists
- Proof-of-Elapsed Time
- Byzantine Fault Tolerance
29. Describe a real-life use-case where Blockchain is being practiced.
In supply chain management, smart contracts give continual transparency and validation of transactions shared by multiple supply chain partners.
30. What is Mining known to as in Bitcoin Blockchain?
Ans. Mining is a method by which all the activities performed in blockchain are primarily verified and then continued to the block. For blockchain mining, specific nodes are committed called miners which practice cryptographic algorithms for the validation and computing the transactions to the block.
To Wrap up!
Blockchain Council is a universally celebrated organization with an absolute group of subject specialists and practitioners who are preaching Blockchain research and improvement, use cases and outcomes and knowledge for a healthier world. Getting approved will help the candidate gain an in-depth perception of the Blockchain & its implementation and demonstrate the Blockchain skills & knowledge. We hope that this articlehelped you in getting a closer look at the interview questions for a perfect job! All the best!