File Info
| Exam | BTA Certified Blockchain Developer - Ethereum |
| Number | CBDE |
| File Name | Blockchain.CBDE.TestKing.2019-10-26.49q.vcex |
| Size | 24 KB |
| Posted | Oct 26, 2019 |
| Download | Blockchain.CBDE.TestKing.2019-10-26.49q.vcex |
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Demo Questions
Question 1
A Hashing Algorithm is deterministic. What does it mean?
- it always produces the same output given the same input.
- it uses equally distributed data to produce the output given a long input.
- it shouldn't be possible to re-generate the input given the output.
Correct answer: A
Question 2
What's the correct scientific notation?
- 1 Ether = 10^18 wei, 10^9 Gwei, 10^3 Finney
- 1 Ether = 10^19 wei, 10^13 Gwei, 10^3 Finney
- 1 Ether = 10^16 wei, 10^13 Gwei, 10^3 Finney
- 1 Ether = 10^18 wei, 10^6 Gwei, 10^6 Finney
Correct answer: A
Question 3
What are Private Keys used for?
- To Protect the Public Keys by being cryptographically significant.
- To Sign Transactions And To Derive an Address From.
- To Generate An Address which can sign transactions.
Correct answer: B
Question 4
Public Keys vs. Private Keys. Which statement is true?
- The Public Key is for Signing Transactions, the Private Key must be given out to verify the signature.
- The Private Key signs transactions, the Public Key can verify the signature.
- The Private Key is to generate a Public Key. The Public Key can sign transactions, the address is here to verify the transactions.
Correct answer: B
Question 5
Proof of Work (PoW) vs. Proof of Stake.
- PoW is computationally intensive which requires lots of energy. On the other hand, miners earn straightforward a reward for mining a block and incorporating transactions.
- PoW is better than PoS, because with PoS we increase the amount of energy spent on the network.
- PoS is mining with specialized new hardware that has to be purchased with a stack of Ether in the network. Hence the Name: Proof of Stake, which derives from Stack.
Correct answer: A
Explanation:
Question 6
Externally Owned Accounts:
- can be destroyed using the selfdestruct keyword. This way all remaining ether will be sent to the receiver address, regardless if they have a fallback function or not.
- are bound to a private key which is necessary to sign transactions outgoing from that account.
- are logical opcodes running on the ethereum blockchain very similar to smart contracts.
Correct answer: B
Question 7
Smart Contracts:
- are always living on the same address, because the blockchain is deterministic. So, one account can always have one smart contract.
- are having the same address as the EOA.
- are sitting on their own address. The Address is created from the nonce and the EOA address and could be known in advance before deploying the smart contract.
- the address of the smart contract is a random address which gets generated by the miner who mines the contract-creation transaction.
Correct answer: C
Question 8
Transactions containing the same data to create the same smart contract are:
- always having the same signature.
- having a different signature because of the nonce which changes upon every transaction.
Correct answer: B
Question 9
Sending one Ether is actually internally translated:
- to Wei, so it will send the equivalent of 10^18 Wei.
- to Finney, so it will send the equivalent of 10^3 Finney.
- to Szabo, so it will send the equivalent of 10^6 Szabo.
Correct answer: A
Question 10
Hashing Mining uses:
- Keccack256 while internally to hash values it's easy to use the Dagger-Hashimoto to create a meaningful hash.
- the Dagger-Hashimoto hashing while internally the EVM uses SHA256 which is an alias for Keccack256.
- the Dagger-Hashimoto hashing while internally the EVM uses Keccack256 which is almost similar to SHA256, but has a different padding so produces different hashes.
Correct answer: C
