basics of blockchain

Any distributed system must make sure that all peers are seeing and working on the same consistent data. This is called...

• Proof of work

• Consensus

• Mining

• Trusted third party

Write the name of a cryptocurrency other than Bitcoin and Ethereum.

Who adds a block to the chain?_

• Miner

• Node

• Block Validator

• None

Double spending is reusing digital assets intentionally or inadvertently. True or False?

• TRUE

• FALSE

What is the purpose of mining in blockchain technology?

• To validate transactions and add new blocks to the blockchain

• To create new cryptocurrency

• To secure cryptocurrency transactions

• To control the supply of cryptocurrencies

What is one of the requirements of secure hashing function?

• It is log function

• It is a one way function

• It is designed to be hard to calculate

• It is a secret function

Answer explanation

It is not designed to be hard to calculate, its inverse is the function that is hard to calculate (even impossible since it is one-way... remember, many inputs give the same output)

Which of the following is NOT a requirement for cryptographic hash functions?

• Pre-image resistance

• 2nd pre-image resistance

• Collusion resistance

• Output must start with a few zeros

What is the use of digital signatures in a blockchain?

• Authenticating transactions

• Mining

• Proof of work

• Hiding transactions

On average, how long does it take for a Bitcoin block to be added to the blockchain?

• 1 minute

• 6 minutes

• 10 minutes

• 1 hour

To have a useful blockchain use-case, which one DON'T we need? (We need three of them, which is the other?)

• More than one entity need to contribute data

• Data records must never be deleted after being written

• We need to hide our confidential data that is written to the blockchain

• Entities contributing data must have a conflict of interest