CSE 598 Blockchain Questions And Answers With
Latest Quiz
Question 1
How are the blocks in Bitcoin linked chronologically to one another? ANS Blocks are connected by every
subsequent block including the hash of the previous block header hash in its block header.
True or False? Changing a transaction in a block also changes the block header. ANS True
Miners adjust the value of the __________________ field, located in the block header, so that the hash of the
block header will be less than or equal to the difficulty target of the network. ANS nonce
Where, if at all, is the current state of the ledger stored on the blockchain in Bitcoin? ANS The current
state is derived from transactions on the blockchain but is not stored on the blockchain.
A blockchain protocol's _______________ algorithm defines the rules that allow its network of participants to
come to an agreement over a single blockchain history. ANS consensus
The ________________ property of blockchains is very beneficial for supply chain applications as it allows
network participants to track the movement of a specific item of interest throughout the supply chain. ANS
Traceability
Analogous to Bitcoin where the state is made up of UTXOs in a UTXO set, what objects make up the state of
Ethereum? ANS accounts
In Bitcoin, is the first transaction of a block a special transaction? ANS Yes, it starts a new coin owned by
the creator of the block
Xthin uses eight bytes of a hash to reference transactions, which is called a "cheap hash."
Technically, why does this eight-byte output not qualify as a hash function? ANS A collision can be found
by using a birthday attack.
What is an example of a successful collision attack on a hash function HASH()? ANS An attacker finds an
m_1m1 and an m_2m2 such that HASH(m_1) = HASH(m_2).
, The MD5 message digest algorithm has an output of 128 bits. If a computer could preform one trillion
(1*10^{12}1∗1012) hashes a second, how long would it take to preform 2^{128}2128 hashes?
It would take __________ years. ANS 1e19
What is it important to consider when choosing a hash function? ANS 1. The difficulty provided to a
normal user when performing the hash, as well as the difficulty an attacker will have at brute forcing a hash
function.
2. The most recent research that identifies vulnerabilities in hash functions.
3. If a salt should be required, and how to apply a salt securely.
True or False? When handling user passwords, the same salt can be used for every user because the salt will
prevent the computation of a rainbow table. ANS False
Which function would be most appropriate for an application to password handling? Such a function should
hinder a rainbow attack. ANS PBKDF2
True or false? Using hash functions to store passwords eliminates the need to broadcast passwords from client
to server and offers a way to render rainbow table attacks infeasible. ANS True
Which of the following hash functions is NOT used in bitcoin? ANS MD5
The security of an Elliptic Curve Digital Signature Algorithm is dependent on the assumption that a particular
discrete logarithm problem is sufficiently hard. The security is also dependent of the sufficiently random
choice of two numbers. What is an example of a compromise that is not an example of a side channel attack?
ANS A quantum computer is manufactured that can solve a discrete logarithm problem associated with an
ECDSA.
Question 2
True or False? Side Channel attacks always render cryptographic protocols insecure and unreliable. ANS
False
Question 1
Latest Quiz
Question 1
How are the blocks in Bitcoin linked chronologically to one another? ANS Blocks are connected by every
subsequent block including the hash of the previous block header hash in its block header.
True or False? Changing a transaction in a block also changes the block header. ANS True
Miners adjust the value of the __________________ field, located in the block header, so that the hash of the
block header will be less than or equal to the difficulty target of the network. ANS nonce
Where, if at all, is the current state of the ledger stored on the blockchain in Bitcoin? ANS The current
state is derived from transactions on the blockchain but is not stored on the blockchain.
A blockchain protocol's _______________ algorithm defines the rules that allow its network of participants to
come to an agreement over a single blockchain history. ANS consensus
The ________________ property of blockchains is very beneficial for supply chain applications as it allows
network participants to track the movement of a specific item of interest throughout the supply chain. ANS
Traceability
Analogous to Bitcoin where the state is made up of UTXOs in a UTXO set, what objects make up the state of
Ethereum? ANS accounts
In Bitcoin, is the first transaction of a block a special transaction? ANS Yes, it starts a new coin owned by
the creator of the block
Xthin uses eight bytes of a hash to reference transactions, which is called a "cheap hash."
Technically, why does this eight-byte output not qualify as a hash function? ANS A collision can be found
by using a birthday attack.
What is an example of a successful collision attack on a hash function HASH()? ANS An attacker finds an
m_1m1 and an m_2m2 such that HASH(m_1) = HASH(m_2).
, The MD5 message digest algorithm has an output of 128 bits. If a computer could preform one trillion
(1*10^{12}1∗1012) hashes a second, how long would it take to preform 2^{128}2128 hashes?
It would take __________ years. ANS 1e19
What is it important to consider when choosing a hash function? ANS 1. The difficulty provided to a
normal user when performing the hash, as well as the difficulty an attacker will have at brute forcing a hash
function.
2. The most recent research that identifies vulnerabilities in hash functions.
3. If a salt should be required, and how to apply a salt securely.
True or False? When handling user passwords, the same salt can be used for every user because the salt will
prevent the computation of a rainbow table. ANS False
Which function would be most appropriate for an application to password handling? Such a function should
hinder a rainbow attack. ANS PBKDF2
True or false? Using hash functions to store passwords eliminates the need to broadcast passwords from client
to server and offers a way to render rainbow table attacks infeasible. ANS True
Which of the following hash functions is NOT used in bitcoin? ANS MD5
The security of an Elliptic Curve Digital Signature Algorithm is dependent on the assumption that a particular
discrete logarithm problem is sufficiently hard. The security is also dependent of the sufficiently random
choice of two numbers. What is an example of a compromise that is not an example of a side channel attack?
ANS A quantum computer is manufactured that can solve a discrete logarithm problem associated with an
ECDSA.
Question 2
True or False? Side Channel attacks always render cryptographic protocols insecure and unreliable. ANS
False
Question 1
