Essential Blockchain Interview Q and A 2025 | iCert Global

Since Blockchain is becoming more and more popular day by day and new and new employment opportunities are being created, it becomes necessary to prepare well for Blockchain interviews if you wish to secure your dream job. This article (and video) will assist you in learning important questions and answers that you must know. Let's proceed!

Blockchain Interview Questions – Easy Level

1. What makes Blockchain and Hyperledger different?
Blockchain is a technology that stores information in blocks.. They are encrypted and connected in a way that no individual can alter them easily. It is either public or private.

2. How would you describe Blockchain technology to someone with no knowledge of it?

Blockchain is like a public digital notebook that keeps track of blocks of information. Once a block is written, it can’t be changed because it has a special code called cryptography. Imagine your school uses Blockchain as a digital report card for each student. Every block is a student record indicating the date and time it was posted. The teacher and the student cannot modify the records after they are saved.

3. What is a Merkle Tree?

A Merkle Tree is a way of checking and organizing the data in a block It’s like a special kind of tree called a binary tree. At the bottom of the tree, there are small pieces of information called leaf nodes. These are cryptographic hashes, or codes for transaction data. Each node above them is a hash obtained by hashing the hashes below.

4. What is the meaning of blocks in Blockchain technology?

Blocks are like boxes in cyberspace that contain information about transactions. Think of Blockchain as a large public database comprised of numerous blocks.

5. What is the difference between a Blockchain ledger and a usual ledger?

A Blockchain distributed ledger would be similar to an electronic notebook which everyone in the network could read and modify. It is not similar to a shared ledger, something which would normally be maintained by one individual or a figure of authority.

6. How do you locate a block?

A block in Blockchain is similar to a unique digital box, and each has a unique ID. Blocks can be represented by four main things:

1. The previous block's hash is like a link to the block before it, connecting all blocks together like a chain.

2. Transaction data – The block holds a bunch of details about what happened (like who sent or received what).

3. Nonce – A random number to aid in solving puzzles to form the block.

4. There are 64 characters, which are a mix of letters and numbers.

7. What is cryptography and what is its role in Blockchain?

Cryptography means the process of making information secure with secret codes. In Blockchain, it makes individuals' identities secure and their transactions secure.

There are two principal keys employed:

• A public key (viewable by anyone)
• A private key (this is like a secret password that only you know)

8. What are the various types of Blockchain?

There are three primary forms of Blockchains:

• Public Blockchain – It is public and accessible to all. Anyone can add new blocks. Bitcoin and Ethereum are some examples.
• Private Blockchain – Fewer individuals (typically from the same company) can append blocks. The remaining individuals can view the blocks but cannot modify them. Example: Blockstack.
• Consortium Blockchain – It's governed by a limited group of trusted users. They are all allowed to see the data. Example: Ripple.

9. What if you attempt to deploy a file containing more than one contract?

If you upload more than one contract that are like instructions or even rules, only the last one that you've uploaded would be utilized. The rest would be disregarded.

10. What is a Genesis Block?

• Genesis Block is the initial block of a Blockchain. It is similar to the first page of a diary.

• It has no block before it.
• It dictates the rules to other blocks, such as how hard it is to make new blocks and how everybody comes to an agreement on updates.

11. How is the hash (block signature) created?

A hash is a type of digital fingerprint on each block. How to create one:

Using the block data, the computer applies a math formula called SHA-256.

Then, that output is secured with the private key of the user using another equation (e.g., ECDSA).

The end result is the digital signature. This is a mark indicating that the block is secure and owned by the original owner.

12. What are some common encryption methods?

These are special math rules that safeguard information:

• SHA-256 - to generate secure hashes.
• RSA – helps people share secrets safely.

• •Triple DES – secures passwords and other data.
• Ethash – utilized in mining Ethereum
• Blowfish protects files and messages from other people.
• 

13. What is a smart contract and how is it used?

Smart contract refers to an independent computer program that executes the instructions coded into it — similar to a robot contract.

Smart contracts are employed for:

• Shipping – monitor products from location to location.
• Copyright – protects music, paintings, or books from being reproduced.
• Insurance – check if a claim is genuine or not.

• Jobs pay individuals automatically when labor is completed.

14. What is Ethereum and what type of networks does it comprise of?

Ethereum is a Blockchain upon which individuals can create apps and smart contracts.

There are 3 types of Ethereum networks:

• Main network – the real network in which real money is spent.
• Test networks are testing grounds like where one can test their apps without spending actual money (e.g., Ropsten and Kovan).
• Private network – employed by firms to operate their own Ethereum network within their office.

15. Where do nodes run smart contract code?

Smart contract code runs on a platform called the Ethereum Virtual Machine (EVM). EVM is similar to an imaginary computer (virtual one) intended to execute only Ethereum programs. It allows you to safely test your smart contracts, without any impact on the live network. You can download the EVM and run your program at home. If it works fine, you can run it on the live Ethereum network where it would be executing.

How to obtain Blockchain certification? 

We are an Education Technology company providing certification training courses to accelerate careers of working professionals worldwide. We impart training through instructor-led classroom workshops, instructor-led live virtual training sessions, and self-paced e-learning courses.

We have successfully conducted training sessions in 108 countries across the globe and enabled thousands of working professionals to enhance the scope of their careers.

Our enterprise training portfolio includes in-demand and globally recognized certification training courses in Project Management, Quality Management, Business Analysis, IT Service Management, Agile and Scrum, Cyber Security, Data Science, and Emerging Technologies. Download our Enterprise Training Catalog from https://www.icertglobal.com/corporate-training-for-enterprises.php and https://www.icertglobal.com/index.php

Popular Courses include:

• Project Management: PMP, CAPM ,PMI RMP

• Quality Management: Six Sigma Black Belt ,Lean Six Sigma Green Belt, Lean Management, Minitab,CMMI

• Business Analysis: CBAP, CCBA, ECBA

• Agile Training: PMI-ACP , CSM , CSPO

• Scrum Training: CSM

• DevOps

• Program Management: PgMP

• Cloud Technology: Exin Cloud Computing

• Citrix Client Adminisration: Citrix Cloud Administration

The 10 top-paying certifications to target in 2025 are:

• Certified Information Systems Security Professional® (CISSP)

• AWS Certified Solutions Architect

• Google Certified Professional Cloud Architect 

• Big Data Certification

• Data Science Certification

• Certified In Risk And Information Systems Control (CRISC)

• Certified Information Security Manager(CISM)

• Project Management Professional (PMP)® Certification

• Certified Ethical Hacker (CEH)

• Certified Scrum Master (CSM)

Conclusion

As Blockchain technology goes far and wide, the demand for people who are aware of it also rises. Being prepared for interviews with proper knowledge—from elementary concepts such as blocks and cryptography to sophisticated concepts such as smart contracts and Ethereum—can place you ahead of the game. Utilize these valuable questions and answers to become more confident and secure your dream Blockchain job in 2025.

Contact Us For More Information:

Visit : www.icertglobal.com     Email : info@icertglobal.com