Blockchain Interview Questions with Answers | Blockchain Works

Blockchain jobs are amongst the most lucrative career opportunities in today’s job market. Almost every forward-looking company in all sorts of industries is implementing blockchain processes in their business modules. They are either doing this through in-house talent or in conjunction with specialist blockchain companies who provide tech consultancy and solutions. This has created a demand for highly skilled professionals who can work on complex blockchain solutions and have a multi-disciplinary skill-set.

Such requirements create a talent gap in the industry. The skills and knowledge possessed by professionals may not live up to the industry standards. To make sure that the right candidate gets the opportunity, recruiters adhere to an interview process that tests an individual’s knowledge around blockchain skills and ideology.

If you are a software developer, marketing professional, or someone who is preparing to get a job at a blockchain company then you must get ready to answer some frequently asked questions for those job interviews.

While questions like what is blockchain? And what are its features? Are the obvious conversation starters, other equally important questions consistently rank as top interview questions. To know the correct way to answer these questions, follow along;

1. Why do you think Blockchain networks are trustworthy? How would you explain it to a layman?

The trustworthiness of blockchain networks is quite ironic because blockchain works in a way that adheres to a trustless process. The need to trust in a process or mechanism is based on the absence of absolute transparency and the presence of an intermediary. Blockchain as a technology eradicates the need for an intermediary through a decentralized network that verifies changes on the ‘Block’ with a consensus algorithm. In such a scenario, there is utmost transparency which makes things work on a blockchain network in a safe and trustless manner. The fact that blockchain networks and databases are not prone to corruption and fraud, makes them highly trustworthy.

2. What are the different types of blockchain networks? Where are they used?

There are mainly three types of blockchain networks, i.e, public, private, and consortium blockchains.

• Public blockchains are accessible to anyone on the internet. Any user can verify transactions and add blocks to these networks. Cryptocurrencies, healthcare records, and government use public blockchain networks.
• Private blockchains are visible to people but can only be verified by those are specified by the owners of that blockchain. Organizations and companies use these blockchain ledgers and they even decide who can read the ledger, and only some of those audience are authorized to verify the changes in it.
• Consortium blockchain ledgers are distributed between a network of organizations and only they can access the ledger. Only pre-selected nodes (or companies/representatives) are allowed to take part in the consensus process who decide on the behalf of the whole network. Unlike private blockchain ledgers, no single organization has the ownership status of the network.

3. What are the various cryptographic algorithms used in the industry?

There are around five most used algorithms in the blockchain industry. The most widely used is the SHA-256. Others are

• Triple DES
• Ethhash
• RSA
• Blowfish

4. What is a smart contract?

A smart contract is a program based on the Ethereum platform that executes automatically when a set of predefined terms, between the peers, are met.

Smart contracts are used in transportation, insurance, copyright, employment contract, etc.

5. What is the difference between Bitcoin and Ethereum?

The main difference between both is that Bitcoin is just a cryptocurrency, whereas Ethereum is a platform that allows other businesses to develop their applications. The Ethereum network has an in-built currency that is called Ether.

As a cryptocurrency, Ethereum is certainly faster than Bitcoin because it settles transactions within seconds.

6. What is Solidity and what is the first thing that is specified in a Solidity file?

Solidity is an object-oriented programming language that is used to write smart contracts. One must specify the Solidity version number and code version number at the beginning. It eliminates compatibility errors while compiling the code with another version.

7. What is the difference between proof of stake and proof of work?

Proof of Work (PoW) is the method of verifying a transaction by solving a mathematical puzzle. This process is also called mining and is an intense computational process that takes up a lot of power.

Proof of stake (PoS) is an alternative where the blockchain goes for distributed consensus. The probability of mining depends upon the miner’s stake in the network. Whereas in PoW, the probability depends upon the computational work. PoS eliminates the heavy electrical power used up to mine blocks.

8. What are the attack risks in a blockchain network?

51% attack is the most evident form of network attack where an individual or a group owns the majority mining power. This allows them to prevent transactions from being confirmed. Mostly, small cryptocurrencies are vulnerable to such attacks, and Proof of Stake is a robust solution to prevent such them.

Conclusion

The above questions are just a glimpse of what recruiters might ask you to test your knowledge around the concerned technology. Some questions will also deal with pure technical aspects that will measure your skills as a developer. It is highly advised that you completely understand the role and its requirements before applying and prepare accordingly.

Looking for a job in the blockchain space? Take a look at our blockchain developer jobs.