The ____________of the tree is the topmost node and hence this tree is represented upside down. The bottommost nodes are called as ________nodes. Each node is simply a cryptographic hash of a transaction.
Answer : B
Explanation:
The root of the tree is the topmost node and hence this tree is represented upside down. The bottommost nodes are called as leaf nodes. Each node is simply a cryptographic hash of a transaction. In the above diagram, Transaction A,B,C,C form the leaves of the tree.
Reference:
https://medium.com/all-things-ledger/bitcoins-implementation-of-blockchain-2be713f662c2
Which of the following blockchain is NOT a permissioned blockchain?
Answer : B
What blockchain is considered Blockchain 1.0, the first blockchain?
Answer : D
Explanation:
Blockchain 1.0, Grandpa Bitcoin -
Reference:
https://hackernoon.com/a-brief-history-in-the-evolution-of-blockchain-technology-platforms-1bb2bad8960a
In the EVM every account has a persistent key-value store mapping 256-bit words to 256-bit words called ________
Answer : C
Explanation:
Every account has a persistent key-value store mapping 256-bit words to 256-bit words called storage.
Reference:
https://solidity.readthedocs.io/en/latest/introduction-to-smart-contracts.html#the-ethereum-virtual-machine
______ is the official Ethereum IDE that allows developers to build and deploy contracts and decentralized applications on top of the Ethereum blockchain.
Answer : B
Explanation:
Mix is the official Ethereum IDE that allows developers to build and deploy contracts and decentralized applications on top of the Ethereum blockchain
What is the language that Solidity is using to build on the Ethereum Virtual Machines(EVM)?
Answer : B
Explanation:
Javascript is the language that Solidity is using to build on the Ethereum Virtual Machine
Reference:
https://www.quora.com/What-is-the-best-programming-language-to-learn-if-you-want-to-work-on-the-blockchain
Regarding Ethereum contracts, the contracts can call (perform) two specific message calls. The message calls are either _____________ or __________?
(Select two.)
Answer : BD
Explanation:
Contracts can call other contracts or send Ether to non-contract accounts by the means of message calls. Message calls are similar to transactions, in that they have a source, a target, data payload, Ether, gas and return data. In fact, every transaction consists of a top-level message call which in turn can create further message calls.
Which of the following hashing algos is considered to be the strongest?
Answer : B
Explanation:
SHA-2 consists of a set of 6 hashing algorithms, and is considered the strongest. SHA-256 or above is recommended for situations are security is vital. SHA-256 produces 32-byte hash values.
Reference:
https://www.securityinnovationeurope.com/blog/page/whats-the-difference-between-hashing-and-encrypting
When you considering cryptography for a blockchain what would be types of symmetric cryptography you could consider? (Select two.)
Answer : AC
Reference:
https://blockgeeks.com/guides/cryptocurrencies-cryptography/
The___________________ is the runtime environment for smart contracts in Ethereum?
Answer : D
Explanation:
EVM The Ethereum Virtual Machine (EVM) is the runtime environment for smart contracts in Ethereum. It is not only sandboxed, but actually completely isolated, which means that code running inside the EVM has no access to network, filesystem, or other processes. Smart contracts even have limited access to other smart contracts.
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?
Answer : D
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
What are some likely repercussions that could occur as a result of a 51% attack to the Bitcoin network? (Select three.)
Answer : ABC
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/
__________ is a real-time gross settlement system (RTGS), currency exchange and remittance network by __________
Answer : A
Explanation:
Ripple is a real-time gross settlement system (RTGS), currency exchange and remittance network by Ripple.
Reference:
https://ripple.com/
A centralized system is one that that is governed by a hierarchical authority.
Which of the following Blockchains would be correctly stated as centralized?
Answer : D
Reference:
https://medium.com/@dustindreifuerst/permissioned-vs-permissionless-blockchains-acb8661ee095
Message Calls in the Ethereum EVM is limited to a depth of ______?
Answer : C
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
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