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Total 229 questions
You are using Geth and you would like to list the accounts controlled by the node.
What is the command?
- A. geth list accounts
- B. geth account node list
- C. geth account node
- D. geth account list
Answer : D
Reference:
https://datawookie.netlify.com/blog/2018/01/ethereum-running-a-node/
___________________ensures that the shared ledgers are exact copies, and lowers the risk of fraudulent transactions, because tampering would have to occur across many places at exactly the same time.
- A. Encryption
- B. Consensus
- C. Validation
- D. Replication
Answer : B
Explanation:
Consensus ensures that the shared ledgers are exact copies, and lowers the risk of fraudulent transactions, because tampering would have to occur across many places at exactly the same time
Reference:
https://www.ibm.com/developerworks/cloud/library/cl-blockchain-basics-intro-bluemix-trs/index.html
Ethereum tries to keep the mining time difference between ____ and _____seconds.
- A. 10, 18
- B. 10, 20
- C. 10, 29
- D. 10, 19
Answer : D
Reference:
https://dltlabs.com/how-difficulty-adjustment-algorithm-works-in-ethereum/
Which of the following cryptocurrencies use an alternate consensus method called "Scrypt" to BTC's Proof of Work (POW) SHA-256 algorithm?
- A. Ripple
- B. Peercoin
- C. Litecoin
- D. Steemit
Answer : C
Explanation:
The Scrypt hash function was initially implemented by the Litecoin development team to avoid what are known, ASICs, from being able mine its cryptocurrency.
When mining for cryptocurrencies, users typically have an option between: a CPU, GPU or ASIC miner.
Reference:
https://www.mycryptopedia.com/litecoin-scrypt-algorithm-explained/
What is chaincode?
- A. Smart contract
- B. DApps
- C. Node programs
- D. Virtual machines
Answer : A
Reference:
http://hyperledger-fabric.readthedocs.io/en/release-1.1/chaincode.html
Addresses on a blockchain are derived by a process of hashing _________.
- A. Wallet Addresses
- B. Private Keys
- C. IP Addresses
- D. Mac addresses
- E. Public Keys
Answer : E
Reference:
https://medium.com/@ConsenSys/blockchain-underpinnings-hashing-7f4746cbd66 b
When considering a new ERC20 token its best to consider using ____________________.
- A. Use a template from AWS
- B. Audited Implementation
- C. Start a new one
- D. Copy from existing token
Answer : A
Reference:
https://medium.com/@merunasgrincalaitis/gain-ethereum-ico-trust-credibility-e9e53145c331
Smart Contracts are generally written in specific programming languages.
Which one is NOT a language for smart contracts?
- A. .Net
- B. Viper
- C. LLL
- D. Solidity
Answer : A
What is diagram referencing below?
- A. AND Gate
- B. XOR Gate
- C. OXR Gate
- D. NAND Gate
Answer : B
Explanation:
XOR or "Exclusive OR" is a logic gate.
Reference:
https://blockgeeks.com/guides/cryptocurrencies-cryptography/
Which of the following is considered the most popular public key encryption algorithm?
- A. RSA
- B. AES
- C. MD5
- D. PGP
Answer : D
Reference:
https://medium.com/@ConsenSys/blockchain-underpinnings-hashing-7f4746cbd66b
Geth uses what port to expose the Ethereum RPC Service?
- A. 2096
- B. 8545
- C. 4096
- D. 2545
Answer : B
Reference:
https://datawookie.netlify.com/blog/2018/01/ethereum-running-a-node/
In Ethereum the difficulty adjustment algorithm is coded in the ___________ file.
- A. calcDifficultyFrontier
- B. block_validator.go
- C. calcDifficultyHomestead
- D. calcDifficultyvalidator.go
Answer : B
Reference:
https://dltlabs.com/how-difficulty-adjustment-algorithm-works-in-ethereum/
What are two advantages of using a DPOS algo in a blockchain? (Select two.)
- A. Scalable
- B. Governance Model
- C. Efficiency
- D. Fast transactions
- E. Centralized
Answer : AD
Explanation:
The advantages of DPoS are that it is scalable and provides fast transaction verification, but the disadvantage is that it partially centralized and the governance model has not been proven effective in a large project. DPoS is employed by Steemit, EOS, and BitShares.
Reference:
https://hackernoon.com/an-overview-of-cryptocurrency-consensus-algorithms-9d744289378f
When writing and considering push and pull in a smart contract that involves "user" funds would it be better to ____________________?
- A. Withdraw funds rather than pull funds to them automatically
- B. Withdraw funds rather than push funds to them automatically
- C. Pull funds rather than push funds to them automatically
- D. Push funds rather than pull funds to them automatically
Answer : B
Explanation:
Withdraw funds rather than push funds to them automatically Favor pull over push for external calls as we've seen, external calls can fail for a number of reasons, including external errors. To minimize the damage caused by such failures, it is often better to isolate each external call into its own transaction that can be initiated by the recipient of the call. This is especially relevant for payments, where it is better to let users withdraw funds rather than push funds to them automatically. (This also reduces the chance of problems with the gas limit.)
Reference:
https://github.com/ethereum/wiki/wiki/Safety#favor-pull-over-push-for-external-calls
When considering tokens on the Ethereum Blockchain what is the main difference between ERC20 and ERC721 tokens?
- A. No difference on Ethereum all tokens are fungible
- B. ERC20 is not fungible while ERC721 tokens are fungible
- C. ERC721 is not fungible while ERC20 tokens are fungible
- D. No difference on Ethernet all tokens are not fungible
Answer : C
Explanation:
Non-fungible means unique. ERC is acronym of Ethereum Request for Comments. A standard allows for the implementation of a standard API for creating non- fungible tokens. To whom not familiar, ethereum, when launched during ICO, is using ERC-20 which ethereum coin can be broken down into smaller portion such as 0.000001. As you know, in coin, we don"™t differentiate it by serial number. Government only uses "serial number" to track the note and not on coin. Hence, there is no way to distinguish or trace your coin and my coin. This behavior is same in Ethereum coin. Startup has found a way to use ERC-721 to create a unique and traceable coin in ethereum blockchain technology. This is a break through in blockchain technology.
Reference:
https://medium.com/@PatrickGohBS/ethereum-erc-721-vs-erc-20-4bff8c147fdf
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