Blockchain CBSA Practice Test - Questions Answers, Page 5

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/

Ripple is a real-time gross settlement system (RTGS), currency exchange and remittance network by Ripple. Reference: https://ripple.com/

Reference: https://medium.com/@dustindreifuerst/permissioned-vs-permissionless-blockchains-acb8661ee095

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

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

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/

Reference: https://www.trymining.com/pages/asic-vs-gpu

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