Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Linux > 6452 Quiz > Flashcards

6452 Quiz Flashcards

1
Q

What is a ledger?

A

append-only list of blocks of transactions (TXs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Ledger structure is….

A

One list, but operators are in a peer-to-peer network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Distributed systems share ______

A

ledgers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the types of DLT systems?

A

Permissionless - no auth required
Permissioned - auth required
Public - accessible to the public
Private - accesible to limited people

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which DLT system is easiest to regulate?

A

Permissioned + Private

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are some examples of permissionless public DLT systems?

A

Bitcoin, Ethereum, Algorand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some examples of Permissioned public DLT systems?

A

Hedera
Ripple
Avalanche

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some examples of permissioned private DLT systems

A

R3 Corda
Quorum
VMware Concord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the difference between a replicated and distributed ledgder

A

Replicated = updated independently by participants
Distributed = updated automatically within minutes, or even instantly such that all users have the same ledger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the possible issues that can arise as a result of growing participants?

A

Inconsistent edgers due to concurrent transactions

Potential for inconsistency with no of ledger copies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why might waiting for an ack message from all participants in a DL system before updating accounts be problematic?

A

It will limit concurrency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How reliable is the use of sender’s time to order transactions?

A

Unreliable as subject to drift and skew and possible change by sender

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why aren’t clocks accurate fro DLT

A

Drift and skew

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is used in place of time in DLT

A

global ordering of transactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does CAP Theorem say?

A

Impossible for web service to provide 3 guarantees at the same time:

Consistency, Availability, Partition tolerance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is partitioning in networks?

A

Where nodes lose connectivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

In order to achieve reliable consensus, what must a DLT have?

A

Partition tolearance
Fault tolerance
Misbehaving nodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does a Transaction (TX) contain?

A

Monetary value (Crypto)
Code
Parameters/results of function calls

To, from, Value/data, Sender’s signature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What forms a block’s body?

A

Collection of ordered TXs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What forms a block’s header

A

Summary of TXs & hash of previous block

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What do nodes agree on?

A

contents of blocks
order of blocks
who has the right to build a block

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does each node do to ensure high availability and efficient read access?

A

Each node hosts a replica of the ledger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

List some beneficial non-functional properties of blockchains

A

Integrity
Availability
latency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

List some downside non-functional properties of blockchain

A

confidentiality
Modifiability
Scalability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

List the 4 different roles that blockchain can play in an architecture

A

Storage
Communication
Computational
Asset management and control

26
Q

can DLT be a standalone system

A

No, requires UI, IoT integration, Key management, databases etc

27
Q

By nature of DLT, is it easy to detect TX failures

A

No, hard to detect errors

28
Q

What are 3 blockchain adoption paradoxes

A

Public blockchains are too transparent for many commercial applications

Who pays? Who chooses Policy?

Future of blockchain is ‘off-chain’

29
Q

Blockchains can store a large volume of data (t/f)

A

False. Need to store off chain as is very expensive

30
Q

Data can be read faster, but writing is slow (t/f)

A

true. recording data is slow as it needs validation

31
Q

Data on blockchain is secure (t/f)

A

false

32
Q

It’s impossible to correct errors in data (t/f)

A

false

33
Q

How else might a replicated and distributed ledger be referred to?

A

Linked list with hash pointers

34
Q

What does a hash do?

A

It takes large volume of data and converts into a small, fixed data size

35
Q

What are some hash algorithms?

A

MD5, SHA, SHA-3, KECCAK

36
Q

list some key properties of hash functions

A

Deterministic = same message results in same hash
Small change to a message -> big difference in hash
Quick to compute
One-way function, cannot invert

37
Q

What is the Merkle Tree?

A

Binary tree built using hashes which allow efficient and secure verification of contents of large data structure

38
Q

What is the pseudo-anonymous feature of an account on a DLT?

A

the public key i.e. ishfbbasfbsdfhuhadqwd338 represents an account

39
Q

What is the base currency of a platform called?

A

Native currency

40
Q

what generation of cryptocurrency is bitcoin built on?

A

1st generation
Miners compete to build the next block

41
Q

What is the averge time between blocks called, and how long is it approximately?

A

inter-block time, approx 10 mins

42
Q

how many nodes are approx in the BTC network?

A

16,896

43
Q

An account is associated with a _______

A

Cryptographic key pair

44
Q

Public key is used to…

A

create the address of an account

45
Q

Private key is used to

A

sign TXs sent from the account

46
Q

How can the state of the blockchain be described?

A

Account balances of all users
Result from the genesis block & set of TXs includeed since
All of the UTXOs in the system

47
Q

What happens, regarding state when a new block is added?

A

the entire system moves from one discrete state to another

48
Q

How is it decided who receives the TX fee?

A

If sum of output < sum of inputs, then fee to miner

49
Q

What does ‘Linked TXs’ mean?

A

Outputs of TXs become inputs of new TX

50
Q

In the transaction format, what is the balance of an address?

A

It is the sum of values of all of UNSPENT TRANSACTION OUTPUTS associated with the address

51
Q

What is referred to as a container of TXs?

A

Blocks

52
Q

What are blocks identified by?

A

block hash

53
Q

What is used to capture ordered list of TXs?

A

Merkle tress

54
Q

What is the max block size, and max TX size

A

block = 4MB, TX = 100k bytes

55
Q

Explain how mining works

A
  1. Recieve a new block
  2. Aggregation - aggregate subset of remaining valid TXs
  3. Header construction - Construct merkle tree to summarise all included TXs
  4. Solve puzzle - find solution to Proof-of-work algorithm (hashcash)
  5. Propogate - immediately propogate new block to other nodes
56
Q

Hashcash is a Proof-of-work that is ….

A

Difficult to compute, easy to validate

57
Q

If multiple miners find and announce next block at the same time

A

longest history of blocks is treated as the main chain (also known as Nakamoto consensus)

58
Q

What are TX fees

A

Miners collect fees
Higher TX feee -> higher chance of TX getting inc. in a block

59
Q

As soon as a Bitcoin TX is included in a block, it is safe to assume the TX is final (T/f)

A

False, as we need to wait for it to go through the mining process to be included in a block

60
Q

How many merkle trees does Ethereum use?

A

3.
one for integrity for:
World state
TXs
TX receipts

Linux (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions