BTA Blockchain Solution Architect Questions + Answers

Post by **answerhappygod** » Tue Apr 05, 2022 8:31 am

Question 1 ( Topic 1 )
SHA-1 is the most commonly used SHA algorithm, and produces a ______-byte hash value(size).
A. 256
B. 128
C. 32
D. 20

Answer : D

Explanation:
SHA-1 is the most commonly used SHA algorithm, and produces a 20-byte hash value.
Reference:
https://www.securityinnovationeurope.co ... encrypting
Question 2 ( Topic 1 )
What type of attack would be considered a very large flaw in public blockchains such as Bitcoin"™s Blockchain where the majority of hashpower could possibly be controlled thru an attack?
What is the specific attack Bitcoin could be exposed to?
A. 51% Attacks
B. Tether Token Hack
C. DDoS Attack
D. BIP attack
E. Parity Wallet Attack

Answer : A

Reference:
https://blockgeeks.com/guides/hypotheti ... urrencies/
Question 3 ( Topic 1 )
How many satoshis are in 1 bitcoin and how many wei in an Ether? (Select two.)
A. 1,000,000,000,000,000,000
B. 1,000,000,000,000,000
C. 1,000,000,000
D. 10,000
E. 1,000,000,000,000

Answer : AB

Reference:
http://www.btcsatoshi.com/
Question 4 ( Topic 1 )
In the Proof of Stake(POS) algorithm the miners are really known as ___________?
A. Notary
B. Oracle
C. Forgers
D. Minters

Answer : C

Explanation:
Proof of Stake has the same goal as proof of work""to validate transactions and achieve consensus in the chain""and it uses an algorithm but with a different process. With proof of stake, the creator of a new block "is chosen in a deterministic way, depending on its wealth, also defined as a stake." Since in a proof of stake system, there is no block reward, but the miners, known as forgers, get the transaction fees. Proponents of this shift, including Ethereum co-founder Buterin, like proof of stake for the energy and cost savings realized to get to a distributed form of consensus.
Reference:
http://www.hl.co.uk/news/2018/2/16/a-br ... hould-read
Question 5 ( Topic 1 )
A Byzantine failure is the loss of a system service due to a Byzantine fault in systems that requires________.
What is required?
A. Consensus
B. Crypthography
C. Bandwidth
D. Availability

Answer : A

Explanation:
A Byzantine failure is the loss of a system service due to a Byzantine fault in systems that require consensus.
Reference:
https://en.wikipedia.org/wiki/Byzantine_fault_tolerance

Question 6 ( Topic 1 )
A ____________cipher basically means it is using a fixed key which replaces the message with a pseudorandom string of characters. It is basically the encryption of each letter one at a time.
What is the cipher type?
A. Stream
B. Block
C. Parallel
D. RSA

Answer : A

Explanation:
Stream cipher basically means using a fixed key which replaces the message with a pseudorandom string of characters. It is basically the encryption of each letter one at a time.
Reference:
https://blockgeeks.com/guides/cryptocur ... ptography/
Question 7 ( Topic 1 )
You currently using the Metamask Chrome plugin and you see a selection for Etherescan in the plugin.
What is Etherscan used for?
A. A search engine that allows users to easily lookup, confirm and validate transaction that have taken place on the Ethereum Blockchain
B. A search engine that allows users to easily lookup, confirm and validate transaction that have taken place on the Bitcoin Blockchain
C. A search engine that allows users to easily lookup, confirm and validate transaction that have taken place on the Ethereum and Tokens Blockchain
D. A search engine that allows users to easily lookup, confirm and validate transaction that have taken place on any Blockchain

Answer : A

Explanation:
A search engine that allows users to easily lookup, confirm and validate transactions that have taken place on the Ethereum Blockchain
Reference:
https://etherscancom.freshdesk.com/supp ... etherscan-
Question 8 ( Topic 1 )
What are two challenges with using a Proof of Work algorithm? (Select two.)
A. Mining pools not allowed
B. Difficulty rate goes done every year.
C. Expensive
D. Power Intensive

Answer : CD

Reference:
http://www.hl.co.uk/news/2018/2/16/a-br ... hould-read
Question 9 ( Topic 1 )
Your customer is an enterprise that is focused on financial sectors.
What type of blockchain would this customer likely want specified for their enterprise?
A. Permissionless
B. Decentralized
C. Hybrid
D. Permissioned

Answer : D

Explanation:
Sometimes referred to as "private" blockchains, you are required to have some sort of permission to access any or parts of that blockchain. There are a multitude of variants and hybrid permissioned/permissionless blockchains that exist.
Reference:

Question 10 ( Topic 1 )
Which is the following is the metaphor that describes a logical dilemma that plagues many computer networks?
A. Neo Generals"™ problem
B. Byzantine Generals"™ problem
C. Byzantine Admirals"™ problem
D. Renaissance Generals"™ problem

Answer : B

Explanation:
BFT is so-named because it represents a solution to the "Byzantine generals' problem," a logical dilemma that researchers Leslie Lamport, Robert Shostak and
Marshall Pease described in an academic paper published in 1982
Reference:
https://www.nasdaq.com/article/byzantin ... s-cm810058

Question 11 ( Topic 1 )
The key difference between encryption and hashing is that encrypted strings can be reversed back into their original decrypted form if you have the right key?
A. TRUE
B. FALSE

Answer : A

Reference:
https://www.securityinnovationeurope.co ... encrypting
Question 12 ( Topic 1 )
What is a logic gate in electronics and computer science?
A. A logic gate usually takes in 2 inputs and gives out 1 output. The inputs and outputs are binary values, meaning they can be both 1 and 0.
B. A logic gate usually takes in 3 inputs and gives out 2 output. The inputs and outputs are binary values, meaning they can be 1 or 0.
C. A logic gate usually takes in 2 inputs and gives out 6 output. The inputs and outputs are binary values, meaning they can be both 1 and 0.
D. A logic gate usually takes in 2 inputs and gives out 1 output. The inputs and outputs are binary values, meaning they can be 1 or 0.

Answer : D

Explanation:
A logic gate usually takes in 2 inputs and gives out 1 output. The inputs and outputs are binary values, meaning they can be 1 or 0. A XOR logic gate takes in 2 binary inputs and gives out a high output ONLY when the inputs are different. Meaning, if A and B are inputted to a XOR gate then the out C will be 1 ONLY when
A is not equal to B.
Reference:
https://blockgeeks.com/guides/cryptocur ... ptography/
Question 13 ( Topic 1 )
Ethereum is considered to be a ______________type of blockchain.
A. Permissionless
B. Permission Based
C. Hybrid
D. Private

Answer : A

Explanation:
Permissionless - anyone can join Anyone can run a node, run mining software/hardware, access a wallet and write data onto and transact within the blockchain
(as long as they follow the rules of the bitcoin blockchain). There is no way to censor anyone, ever, on the permissionless bitcoin blockchain.
Reference:

Question 14 ( Topic 1 )
Your company working for is now considering the blockchain. They would like to perform a POC with R3 Corda. The CIO was reading about different blockchain consensus algos and would like to understand what type of consensus algos is used with Corda.
What is the best answer?
A. R3 Corda is a pluggable blockchain and allows the enterprise flexibility
B. R3 Corda is a byzantine fault tolerant blokchain
C. R3 Corda is a proof of stake based blockchain
D. R3 Corda is a proof of work based blockchain

Answer : A

Explanation:
Corda does not share the same requirements as Bitcoin: we require absolute certainty over transaction finality and we need to know who our counterparts are. So we had the freedom "" and took this opportunity "" to solve the consensus problem in a different way. In particular, Corda solves the privacy issue in a number of manners, primarily by allowing for separation of consensus into a service which we call the Notary Cluster. Corda was designed for business from the start. It has no cryptocurrency built into the platform and does not require mining-style consensus, which imposes great cost with little business benefit.
Question 15 ( Topic 1 )
Secure Hash Algorithm (SHA-256) output is always 256 bits or 32 bytes in length regardless of the length of the input (even if input is millions of bytes). Select best answer.
A. NSA is spying on us so what"™s it matters.
B. Depends on input
C. False
D. True

Answer : D

Explanation:
SHA stands for Secure Hash Algorithm. This is used to prove data integrity. The same input(s) will always produce the exact same output. This output is always
256 bits or 32 bytes in length regardless of the length of the input (even if input is millions of bytes).
Reference:

Question 16 ( Topic 1 )
In the Ethereum EVM there are two types of memory areas. (Select two.)
A. Storage
B. Database
C. Memory
D. Persistent
E. Ephemeral

Answer : AC

Reference:
https://solidity.readthedocs.io/en/late ... al-machine
Question 17 ( Topic 1 )
What are some advantages of Proof of Stake(POS) mining over Proof of Work(POW) mining? (Select three.)
A. Energy efficient in regards to that it could consume for electricity as compared to PoW
B. Faster Hashing algorithms
C. No need for expensive compared to POW
D. Faster validations compared to POW
E. Better blockchain security compared to POW

Answer : ACD

Explanation:
This eliminates the below challenges from PoW and believed to have an advantage.
No need of expensive hardware (a normal laptop or computer running the respective coin"™s Validator client will do as long as your laptop or computer is online)
Energy efficient as it won"™t consume high electricity as PoW does More loyal Validators As higher the stake the Validators have for a long time, more chances for the Validator to be picked up for "forging" and earn the transaction fee Faster validations
Reference:
https://medium.com/@karthik.seshu/crypt ... eee1420b10
Question 18 ( Topic 1 )
Application Specific Integrated Circuit (ASIC) are used always in enterprise blockchains.
A. TRUE
B. FALSE

Answer : B

Explanation:
ASICS are generally used in blockchains such as BTC that have a Proof of Work consensus due to competition
Reference:
https://www.trymining.com/pages/asic-vs-gpu
Question 19 ( Topic 1 )
What type of encryption is shown below and is commonly used in blockchain cryptography?

A. Diffie-Hellman
B. Asymmetric Encryption
C. Synchronous
D. Asynchronous
E. Symmetric Encryption

Answer : B

Explanation:
Asymmetric cryptography utilizes two different keys, a public key and a private to encrypt and decrypt a particular data. The use of one key cancels out the use of the other.
Reference:
https://blockgeeks.com/guides/cryptocur ... ptography/
Question 20 ( Topic 1 )
An encryption algorithm transforms plain text into cipher text using a key?
A. TRUE
B. FALSE

Answer : A

Question 21 ( Topic 1 )
The gas price is a value set by the creator of the blockchain transaction? (Select best answer.)
A. FALSE
B. Its Negotiable
C. TRUE

Answer : C

Explanation:
The gas price is a value set by the creator of the transaction, who has to pay gas_price * gas up front from the sending account. If some gas is left after the execution, it is refunded in the same way. If the gas is used up at any point (i.e. it is negative), an out-of-gas exception is triggered, which reverts all modifications made to the state in the current call frame.
Reference:
https://solidity.readthedocs.io/en/late ... al-machine
Question 22 ( Topic 1 )
R3 Corda does not organize time into blocks. What does Corda actually perform and use?

A. Ripple is implemented as the blockchain and XRP for cryptocurrency.
B. Notary services and timesmapping
C. R3 Corda is a blockchain and does use blocks
D. Notary services and timestamping

Answer : D

Explanation:

Review Technical Whitepaper -
https://www.corda.net/
Corda network has one or more notary services which provide transaction ordering and timestamping services, thus abstracting the role miners play in other systems into a pluggable component.
Question 23 ( Topic 1 )
Contracts live on the blockchain in an Ethereum-specific binary format called _____________?
A. EOS
B. EVM Code
C. Ether
D. Gas
E. EVM Bytecode

Answer : E

Explanation:
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.
Question 24 ( Topic 1 )
Bitcoin uses what proof of work consensus system?
A. Cubehash512
B. Scrypt-Jane
C. Whirlpool
D. Scrypt-n
E. Hashcash

Answer : E

Explanation:
Bitcoin uses the Hashcash proof of work system.
Reference:
https://en.bitcoin.it/wiki/Hashcash
Question 25 ( Topic 1 )
An _____________ is a well-known service that signs transactions if they state a fact and that fact is considered to be true. They may optionally also provide the facts.
A. notary
B. oracle
C. node
D. endpoint

Answer : B

Explanation:
An oracle is a well known service that signs transactions if they state a fact and that fact is considered to be true. They may also optionally provide the facts r 3
Corda Technical Whitepaper.

Question 26 ( Topic 1 )
Select the two kinds of accounts in Ethereum which share the same address space. (Select two.)
A. Gas Account
B. Contract Accounts
C. External Accounts
D. Internal Accounts
E. dApp Accounts

Answer : BC

Question 27 ( Topic 1 )
The most popular Ethereum development framework is currently Truffle.
What are three features of Truffle? (Select three.)
A. Scriptable deployment & migrations framework.
B. Automated contract testing with Mocha and Chai.
C. Takes Dapp transactions via Ws-rpc, json-rpc, ipc-rpc.
D. Built-in smart contract compilation, linking, deployment and binary management.
E. Automated contract testing with Mocha only

Answer : ABD

Explanation:
Truffle is a development environment, testing framework and asset pipeline for Ethereum, aiming to make life as an Ethereum developer easier.
Reference:
https://github.com/trufflesuite/truffle
Question 28 ( Topic 1 )
You are considering writing smart contracts and there are a few different languages you can consider. (Select two.)
A. Truffle
B. Serpent
C. Solidity
D. Embark

Answer : BC

Explanation:
To write smart contracts there are a few different languages: Solidity, which is like JavaScript and has .sol as a file extension, Serpent, Python-like with extension
.se, and a 3rd, LLL, based on Lisp. Serpent was popular a while back but Solidity is the most popular right now and more robust, so just use Solidity. You prefer
Python? Use Solidity.
Reference:

Question 29 ( Topic 1 )
Satoshi Nakamoto invented a way to achieve Decentralized Consensus?
A. TRUE
B. FALSE

Answer : A

Reference:
https://www.interlogica.it/en/insight-e ... consensus/
Question 30 ( Topic 1 )
Which of the following would NOT be true about what a smart contract gives your organization?
A. Accuracy
B. Savings
C. Autonomy
D. Trust
E. Legal Assurance

Answer : E

Explanation:
Smart contracts generally are not legal contracts. However, its possible that a smart contract could be accepted as a legal contract but not normally. Read more about Smart contracts here
Reference:
https://blockgeeks.com/guides/smart-contracts/

Question 31 ( Topic 1 )
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.

In the above diagram, Transaction A,B, C,C from the leaves of the tree. Select one.
A. Root, Hash
B. Root, Leaf Nodes
C. Has, Root nodes
D. Leaf nodes, Root
E. Leaf Nodes, Root

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:

Question 32 ( Topic 1 )
Which of the following blockchain is NOT a permissioned blockchain?
A. Quantum
B. Ethereum
C. R3 Corda
D. Ripple
E. Hyperledger

Answer : B

Question 33 ( Topic 1 )
What blockchain is considered Blockchain 1.0, the first blockchain?
A. Bitcoin Cash
B. Ethereum
C. Litecoin
D. Bitcoin
E. NEO

Answer : D

Explanation:

Blockchain 1.0, Grandpa Bitcoin -
Reference:
https://hackernoon.com/a-brief-history- ... b2bad8960a
Question 34 ( Topic 1 )
In the EVM every account has a persistent key-value store mapping 256-bit words to 256-bit words called ________
A. Gas
B. Space
C. Storage
D. Datastore
E. Database

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/late ... al-machine
Question 35 ( Topic 1 )
______ is the official Ethereum IDE that allows developers to build and deploy contracts and decentralized applications on top of the Ethereum blockchain.
A. Mist
B. Mix
C. Truffle
D. Metamask
E. Embark

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

Question 36 ( Topic 1 )
What is the language that Solidity is using to build on the Ethereum Virtual Machines(EVM)?
A. .Net
B. Javascript
C. C++
D. Node.js
E. PHP

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- ... blockchain
Question 37 ( Topic 1 )
Regarding Ethereum contracts, the contracts can call (perform) two specific message calls. The message calls are either _____________ or __________?
(Select two.)
A. Bitcoin nodes
B. Send Ether to non-contract
C. DApps
D. Other contracts
E. Ether Nodes

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.
Question 38 ( Topic 1 )
Which of the following hashing algos is considered to be the strongest?
A. RSA
B. SHA-2
C. AES
D. MD-5
E. SHA

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.co ... encrypting
Question 39 ( Topic 1 )
When you considering cryptography for a blockchain what would be types of symmetric cryptography you could consider? (Select two.)
A. Block Ciphers
B. Rivest-Shamir-Adleman algorithm aka the RSA.
C. Stream Ciphers
D. Elliptical Curve Cryptography

Answer : AC

Reference:
https://blockgeeks.com/guides/cryptocur ... ptography/
Question 40 ( Topic 1 )
The___________________ is the runtime environment for smart contracts in Ethereum?
A. Metamask
B. Ether
C. Mist
D. EVM

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.

Question 41 ( Topic 1 )
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?
A. Proof of Stake
B. Byzantine Fault Tolerance
C. Proof of Burn
D. Proof of Work
E. Dynamic Proof of Stake

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:

Question 42 ( Topic 1 )
What are some likely repercussions that could occur as a result of a 51% attack to the Bitcoin network? (Select three.)
A. Unplanned Fork
B. Double Spending
C. Cancelling Transactions
D. Planned Fork
E. Selfless Mining

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/hypotheti ... urrencies/
Question 43 ( Topic 1 )
__________ is a real-time gross settlement system (RTGS), currency exchange and remittance network by __________
A. Ripple, Ripple
B. Ripple, JP Morgan
C. XRP, Ripple
D. Ripple, XRP

Answer : A

Explanation:
Ripple is a real-time gross settlement system (RTGS), currency exchange and remittance network by Ripple.
Reference:
https://ripple.com/
Question 44 ( Topic 1 )
A centralized system is one that that is governed by a hierarchical authority.
Which of the following Blockchains would be correctly stated as centralized?
A. Monero
B. Ethereum
C. Bitcoin Cash
D. Ripple

Answer : D

Reference:

Question 45 ( Topic 1 )
Message Calls in the Ethereum EVM is limited to a depth of ______?
A. 128
B. 256
C. 1024
D. 2048

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/late ... al-machine

Question 46 ( Topic 1 )
In the Bitcoin blockchain the "block creation time" is set to 10 minutes and this can never change.
A. FALSE
B. TRUE

Answer : B

Explanation:
Remember, that the block creation time is set to 10 minutes and this can never change. So after a fixed time of approximately 2 weeks or exactly 2016 blocks the difficulty is re-adjusted. Increase in difficulty means target decreases.
Reference:

Question 47 ( Topic 1 )
What is another name for blockchains that run adjacent to the blockchains and also offer more scope for processing contracts?
A. Adchains
B. Funnelchains
C. Multichains
D. Sidechains

Answer : D

Explanation:
Sidechain is another name for blockchains that run adjacent to Bitcoin and offer more scope for processing contracts.
Reference:
https://gendal.me/2014/10/26/a-simple-e ... idechains/
Question 48 ( Topic 1 )
What are two cryptocurrencies that you would expect to see mining equipment with ASICS? (Select two.)
A. Bitcoin
B. Ethereum
C. Neo
D. Litecoin
E. Monero

Answer : AD

Reference:
https://www.trymining.com/pages/asic-vs-gpu
Question 49 ( Topic 1 )
Vitalik Buterin referred to this concept of trust beyond just currency as "˜smart contracts"™ or even blockchain-based "decentralized autonomous organizations" (DAOs).
Ethereum is considered Blockchain version?
A. 2.0
B. 4.0
C. 3.0
D. 1.0

Answer : A

Explanation:
2.0 Ethereum came after Bitcoin. Vitalik Buterin, one of the writers for Bitcoin Magazine that tried to popularize the technology in the early 2012. He witnessed first-hand the problems in the Bitcoin implementation like wasteful mining hardware, centralized mining community, and lack of network scalability. In 2013, the then 19 year old Vitalik described his vision for Ethereum by extending the concept of Bitcoin beyond just currency. He proposed a platform where developer community and entrepreneurs to build distributed application (Dapps) for the Blockchain network. He referred to this concept of trust beyond just currency as "˜smart contracts"™ or even blockchain-based "decentralized autonomous organizations" (DAOs).
Reference:
https://hackernoon.com/a-brief-history- ... b2bad8960a
Question 50 ( Topic 1 )
Ethereum is a programmable blockchain. What is one of the following reasons is NOT correct regarding Ethereum programmability?
A. Allows users to create their own operations on any complexity
B. It serves as a platform for many different types of decentralized blockchain applications
C. Does not allow users to create their own operations of any complexity
D. Ethereum also includes a peer-to-peer network protocol

Answer : C