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Blockchain CBSA Practice Test - Questions Answers, Page 5
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Question 41
Blockchains are decentralized ledgers which, by definition, are not controlled by a central authority. Due to the value stored in these ledgers, bad actors have huge economic incentives to try and cause faults.
What algo was the original solution to the potential problem as specified by Satoshi?
Explanation:
The big breakthrough when Bitcoin was invented, was the use of Proof-of-Work as a probabilistic solution to the Byzantine Generals Problem as described in depth by Satoshi Nakamoto.
Reference: https://medium.com/loom-network/understanding-blockchain-fundamentals-part-1-byzantine-fault-tolerance-245f46fe8419
Question 42
What are some likely repercussions that could occur as a result of a 51% attack to the Bitcoin network? (Select three.)
Explanation:
The 4 main attacks that can happen directly as a result of the 51% attack are: Selfish mining. Cancelling transactions. Double Spending. Random forks.
Reference: https://blockgeeks.com/guides/hypothetical-attacks-on-cryptocurrencies/
Question 43
__________ is a real-time gross settlement system (RTGS), currency exchange and remittance network by __________
Explanation:
Ripple is a real-time gross settlement system (RTGS), currency exchange and remittance network by Ripple. Reference: https://ripple.com/
Question 44
A centralized system is one that that is governed by a hierarchical authority. Which of the following Blockchains would be correctly stated as centralized?
Explanation:
Reference: https://medium.com/@dustindreifuerst/permissioned-vs-permissionless-blockchains-acb8661ee095
Question 45
Message Calls in the Ethereum EVM is limited to a depth of ______?
Explanation:
Calls are limited to a depth of 1024, which means that for more complex operations, loops should be preferred over recursive calls.
Reference: https://solidity.readthedocs.io/en/latest/introduction-to-smart-contracts.html#the-ethereum-virtual-machine
Question 46
In the Bitcoin blockchain the "block creation time" is set to 10 minutes and this can never change.
Explanation:
Remember, that the block creation time is set to 10 minutes and this can never change. So after a fixed time of approximately 2 weeks or exactly 2016 blocks the difficulty is re-adjusted. Increase in difficulty means target decreases.
Reference: https://medium.com/all-things-ledger/decoding-the-enigma-of-bitcoin-mining-f8b2697bc4e2
Question 47
What is another name for blockchains that run adjacent to the blockchains and also offer more scope for processing contracts?
Explanation:
Sidechain is another name for blockchains that run adjacent to Bitcoin and offer more scope for processing contracts.
Reference: https://gendal.me/2014/10/26/a-simple-explanation-of-bitcoin-sidechains/
Question 48
What are two cryptocurrencies that you would expect to see mining equipment with ASICS? (Select two.)
Explanation:
Reference: https://www.trymining.com/pages/asic-vs-gpu
Question 49
Vitalik Buterin referred to this concept of trust beyond just currency as 'smart contracts' or even blockchain-based "decentralized autonomous organizations" (DAOs).
Ethereum is considered Blockchain version?
Explanation:
2.0 Ethereum came after Bitcoin. Vitalik Buterin, one of the writers for Bitcoin Magazine that tried to popularize the technology in the early 2012. He witnessed first-hand the problems in the Bitcoin implementation like wasteful mining hardware, centralized mining community, and lack of network scalability. In 2013, the then 19 year old Vitalik described his vision for Ethereum by extending the concept of Bitcoin beyond just currency. He proposed a platform where developer community and entrepreneurs to build distributed application (Dapps) for the Blockchain network. He referred to this concept of trust beyond just currency as 'smart contracts' or even blockchain-based "decentralized autonomous organizations" (DAOs).
Reference: https://hackernoon.com/a-brief-history-in-the-evolution-of-blockchain-technology-platforms-1bb2bad8960a
Question 50
Ethereum is a programmable blockchain. What is one of the following reasons is NOT correct regarding Ethereum programmability?
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