Certified Blockchain Developer Ethereum Flashcards

1
Q

What is a sandbox?

A

A test environment that isolates untested code changes and experimentation from the production environment.

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2
Q

Name 4 characteristics of the EVM

A

1) Sandboxed VM
2) Runs on every node
3) Turing complete
4) Transaction based state machine

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3
Q

The blockchain is ………………. which means: The same input will always produce the same output.

A

Deterministic

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4
Q

What does hashing do with regards to hash size?

A

Map data of an arbitrary size to data of a fixed size.

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5
Q

Which hash function does Ethereum use?

A

Keccak-256 (which is like SHA256, but the two are NOT interchangeable)

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6
Q

List in order from lowest to highest the Ether denominations (up to one Ether)

A
Wei
Kwai (Ada, Femtoether)
Mwei (Babbage, picoether)
Gwei (Shannon, nanoether, nano)
Szabo (microether, micro)
Finney (milliether, milli)
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7
Q

Kwei is also known as ………………. and ………………..

A

Ada

Femtoether

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8
Q

Mwei is also known as ……………… and ………………..

A

Babbage

Picoether

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9
Q

Gwei is also known as ………………. and ……………….

A

Shannon
Nanoether
Nano

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10
Q

What do you call 1000 ETH?

A

Kether
Grand
Einstein

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11
Q

What do you call 1 million ETH

A

Mether

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12
Q

What do you call a billion ETH?

A

Gether

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13
Q

What do you call a trillion ETH?

A

Tether

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14
Q

An ethereum address is bound to a ………………….

A

Private key

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15
Q

Describe an Ethereum address

A

64 character
32 bit hex value.

It is bound to the private key.

  • The public key is derived from the private key
  • The address is derived from the public key
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16
Q

What are the defining characteristics of POW?

A

mathematical riddle.
resource intensive
The input parameters for a hashed value has to be found
brute force, continuously hashing until the solution is found
Anyone can be a miner

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17
Q

What are the characteristics of POS?

A

There is no mining
Uses few resources
Stakeholders lock-in some money and are picked in a semi-random way to forge a new block
Anyone can be a forger

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18
Q

What is “stake” in the crypto world?

A

The cryptocurrency a user owns and pledges in order to partake in validation  (POS)

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19
Q

How do Proof-of-Stake algorithms achieve consensus?

A

By requiring users to stake an amount of their tokens so as to have a chance of being selected to validate blocks of transactions, and get rewarded for doing so.

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20
Q

What is the incentive for good behaviour in a POS?

A

Payout in the form of transaction fees (as opposed to freshly created currency in PoW systems)

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21
Q

Name two types of account in the Ethereum network.

A

1) Externally owned accounts (EOS’s)

2) Smart contracts

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22
Q

An EOA is controlled by a ………………..

A

Private key (owned by an individual)

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23
Q

A Smart Contract has an …………….. of its own

A

Address

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24
Q

To send a transaction, which fields have to be set?

A
Nonce
Gasprice
Startprice 
To
Value
Data
v,r,s
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25
Q

What is a replay attack?

A

A form of network attack in which a valid data transmission is maliciously or fraudulently repeated or delayed.

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26
Q

What is a nonce?

A

Nonce is a randomly-generated, cryptographic token that is used to prevent replay attacks.

In Ethereum, every transaction has a nonce. It is the number of transactions sent from a given address.

In cryptography is a one-time code selected in a random or pseudo-random manner that is used to securely transmit the main password, preventing a replay attack

Each time you send a transaction, the nonce increases by 1.

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27
Q

What is the notation for wei?

A

10^18

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28
Q

What is the notation for kwei?

A

10^15

29
Q

What is the notation for mwei?

A

10^12

30
Q

What is the notation for gwei?

A

10^9

31
Q

What is the notation for szabo?

A

10^6

32
Q

What is the notation for finney?

A

10^3

33
Q

What is the notation for kether?

A

10^-3

34
Q

What is the notation for mether?

A

10^-6

35
Q

What is the notation for gether?

A

10^-9

36
Q

What is the notation for tether?

A

10^-12

37
Q

What are private keys for?

A

To sign transactions.

To derive the public key from (and also the address)

38
Q

Geth is an Ethereum …………….

A

client

39
Q

What are opcodes?

A

The low level human readable instructions of the program. All opcodes have their hexadecimal counterparts, eg “MSTORE” is “0x52”, SSTORE” is “0x55”

40
Q

What is Dagger Hashimoto and what superseded it?

A

It is an implementation and specification for the mining algorithm.

Ethash superseded it.

41
Q

Name the two popular Ethereum protocols

A

1) Go-Ethereum (aka Geth) - written in GO

2) Parity - written in Rust

42
Q

How do Ethereum nodes communicate with each other?

A

Using the Ethereum protocol

43
Q

How can you connect to an Ethereum node from the outside world?

A

Usually possible though:

  • HTTP (JSON-RPC)
  • IPC

Sometimes:
- Websockets

44
Q

Every Ethereum node must implement a …………… interface.

A

JSON-RPC

45
Q

What does dApp stand for?

A

Distributed application

46
Q

What can dApps do? (2)

A

From simple p2p value transfer

To complicated token structures and more

47
Q

Why to Smart Contracts make value transfer extremely easy? (2)

A

Because the economics and the logic are on the same layer.

Additionally, you can save hardware and configuration by deploying the logic directly on the blockchain.

48
Q

What is the nonce-field in a transaction?

A

To protect against replay attacks

49
Q

The EVM is sandboxed, what is the implication of this?

A

It can’t access hardware layers or anything outside a blockchain node.

50
Q

Name some advantages of dApps (4)

A
  • Cutout the middle man
  • Run on a trusted platform
  • Apply logic to the blockchain where already economic assets are running
  • Allow peer to peer trade.
51
Q

What does a Hashing Algorithm is deterministic mean?

A

Given the same input it always produces the same output

52
Q

What Are Private Keys for?

A

To Sign Transactions and to derive a public key from which an address is determined

53
Q

The………… Key signs transactions, the ………. key can verify the signature

A

Private

Public

54
Q

………. is computationally intensive which requires lots of energy. On the other hand, miners earn straightforward a reward for mining a block and incorporating transactions.

A

PoW

55
Q

What are Externally Owned Accounts?

A

Are bound to a private key which is necessary to sign transactions outgoing from that account

56
Q

Transactions containing the same data to create the ………… smart contract are having a different signature because of the ……….. which changes upon every transaction

A

same

nonce

57
Q

Sending one Ether is internally translated to ……..

A

Wei, so it will send the equivalent of 10^18 Wei

58
Q

Mining uses the …………… hashing while internally the EVM uses …………… which is similar to SHA256, but has different padding so it produces different hashes

A

Dagger-Hashimoto

Keccack256

59
Q

Externally Owned Accounts keep their ……………, but on the blockchain a ………. is increased every time they send a transaction to avoid replay attacks

A

address

nonce

60
Q

What is Ethereum?

A

A protocol defining how the communication should work.

It is neither a proprietary software, nor patent.
Instead it is open and there are several different implementations of the Ethereum protocol.

61
Q

Name two implementations of the Ethereum protocol.

A

Go-ethereum a.k.a GETH (written in GO)

Parity (written in Rust)

62
Q

In Ethereum everyone can start their own………… based on the Ethereum protocol. This means that the………… can be replicated in a way so that it works exactly the same way but doesn’t …………………….

A

blockchain
Main-Net
Cost any real money

63
Q

What are test networks usually used for?

A

To test distributed Applications (dApps)

To test new network functionalities, such as Proof of Stake.

64
Q

What is the Ethereum network ID 0 called, and what is it used for?

A

Olympic, Ethereum public pre-release testnet

65
Q

What is the Ethereum network ID 1 called, and what is it used for?

A

Frontier, Homestead, Metropolis, the Ethereum public main network

66
Q

What is the Ethereum network ID 1 (chain ID 61) called, and what is it used for?

A

Classic, the (un)forked public Ethereum Classic main network.

67
Q

What is the Ethereum network ID 1 (chain ID 2) called, and what is it used for?

A

Expanse, an alternative Ethereum implementation.

68
Q

What is the Ethereum network ID 2 called, and what is it used for?

A

Morden, the public Ethereum testnet, now Ethereum Classic testnet

69
Q

What is a TX pool?

A
  1. Where transactions go before they are added to the blockchain.