9 Job Interview Questions to Ask a Blockchain Developer

9 Job Interview Questions to Ask a Blockchain Developer

One of the toughest parts of the hiring process, regardless of the role, is asking precisely the right questions to validate a candidate’s level of expertise. This can be even more challenging when hiring blockchain developers – especially if you are still learning the ins and outs of this complex new technology yourself. Before you even reach the interview stage, of course, you should ensure they’ve been vetted as an excellent software engineer. Leveraging our years of experience hiring blockchain pros, Ubik Group has compiled nine high-level interview questions to ask developers in order to gauge their knowledge. We also included the answers you should expect to hear from the most proficient candidates.

What are the main benefits to blockchain technology? Answers may include transparency, accuracy, efficiency, speed and/or security. Blockchain’s distributed ledger technology represents a decentralized “trustless” system – in technical terms, a database of immutable records managed by a cluster of computers versus a single entity. 

Provide some examples of industries that are being reshaped by blockchain technology, and how. In retail, blockchain has enabled visibility along the food supply chain, increasing trust and brand loyalty among customers and reducing cases of food contamination. In healthcare, blockchain has improved electronic medical records and is even starting to facilitate faster development of new drugs. Other industries seeing big changes are law, finance, and agriculture.

What are the four components of a blockchain ecosystem? The four components of any blockchain ecosystem are as follows: 1) a node application, 2) a shared ledger, 3) a consensus algorithm, and 4) a virtual machine.

What is the role of encryption in blockchain technology? Blockchain heavily relies on encryption in order to secure data. Blocks are secured and authenticated by using encryption – the process by which data is scrambled and encoded when it is being sent across a network. Encryption in blockchain is rooted in asymmetric cryptography (also known as public-key cryptography), which is a more advanced version of symmetric cryptography.

Can you modify the data in a block? No, you cannot. Once the information has been saved, you would need to delete all information that rests on other associated blocks in order to make any modifications.

How many types of blockchain exist, and what are the differences between them? There are three types of blockchain: Public, Private, and Consortium. In a Public blockchain, anyone with an internet connection and a computer can set up as a node and sync with the full blockchain history. In a Private blockchain, access can be restricted by one party who has control; this means that information is no longer decentralized and therefore not as secure as in a Public or Consortium blockchain. In a Consortium blockchain, power is not held by only one party, but by a trusted ‘council’ who determine access.

Name some of the popular blockchain platforms on the market. Answers may include Ethereum, Ripple, R3 Corda, Quorum, Hyperledger Fabric, Multichain, Hydrachain, BigChainDB, Openchain, or IOTA.

What is a trapdoor function and why is it needed? A trapdoor function is a function that is simple to compute in one direction, but difficult to compute in the reverse direction without special information. Public key encryption relies on trapdoor functions in order to secure data.

How many types of records are present in the blockchain database? The two types of records present in any given blockchain database are Transactional Records and Block Records.


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