C839 Practice with 100- correct answers

C839 Practice with
100% correct answers
Which block cipher modes can be used to turn a block cipher into a
stream cipher? Select two.
a) Electronic Code Book (ECB) mode
b) Propagating Cipher Block Chaining (PCBC) mode
c) Counter (CTR) mode
d) Output Feedback (OFB) mode - answer c) Counter (CTR) mode
d) Output Feedback (OFB) mode


What are reasons certificates should have an expiration date? Select
all that apply
a) Decreases attacker work factor
b) Decreases risk of compromise
c) To facilitate recovery from compromise
d) Creates forced opportunity for users to update certificate
information - answer b) Decreases risk of compromise
c) To facilitate recovery from compromise
d) Creates forced opportunity for users to update certificate
information


What are reasons certificates should have an expiration date? Select
all that apply
a) Decreases attacker work factor
b) Decreases risk of compromise
c) To facilitate recovery from compromise

,d) Creates forced opportunity for users to update certificate
information - answer b) Decreases risk of compromise
c) To facilitate recovery from compromise
d) Creates forced opportunity for users to update certificate
information


What phase of the certificate lifecycle does certificate expiration
and certificate renewal reside in?
a) Setup and Initialization Phase
b) Administrative Phase
c) Cancelation and History Phase
d) Update and Patch Vulnerabilities Phase - answer c) Cancelation
and History Phase


The basic premise of the birthday paradox involves knowing the
number of people you would need in room to have _____ of two
people being born on the same month and day.
a) a guarantee
b) weak probability
c) strong likelihood
d) least chances - answer c) strong likelihood


The birthday paradox concept is employed in the birthday attack on
hashes in effort to identify _____ of a given hash.
a) the number of bits
b) the number of bytes
c) a collision
d) a coefficient - answer c) a collision

,In applying the birthday paradox, with a room containing 23 people,
what is the likelihood two of those 23 people were born on the same
month and day?
a) Guaranteed (100% likelihood)
b) Not likely (0% likelihood)
c) Fifty-fifty (50% likelihood)
d) Equal to the number of people (23% likelihood) - answer c) Fifty-
fifty (50% likelihood)


What is the basic path for certificate requests from a user?
a) User Registration Authority Certificate Authority
b) User Certificate Authority Registration Authority
c) User Certificate Authority
d) User Subordinate Registration Authority - answer a) User
Registration Authority Certificate Authority


Which National Security Agency (NSA) type is Skipjack classified as?
a) Type 1
b) Type 2
c) Type 3
d) Type 4 - answer b) Type 2


Which German Federal Office for Information Security (BSI) criteria
for random number generators states it should be impossible for
any attacker to calculate, or otherwise guess, from any given
subsequence, any previous or future values in the sequence?
a) K4
b) K3
c) K2
d) K1 - answer b) K3

, A _________ adds a key to a hash to improve integrity.
a) Compliment
b) Hash Message Authentication Code (HMAC)
c) Crypto sync
d) Hash Managed Algorithm (HMA) - answer b) Hash Message
Authentication Code (HMAC)


Of the choices below, which entails an attacker discovering a
functionally equivalent algorithm for encryption and decryption, but
without learning the key in cryptanalysis?
a) Total break
b) Total Deduction
c) Global Deduction
d) Global break - answer c) Global Deduction


Of the choices below, select the ones that are prime numbers.
Select Two
a) 71
b) 72
c) 73
d) 74 - answer a) 71
c) 73


Of the choices below, select the ones that are included in an X.509
certificate.
a) Version
b) Certificate holder key pair
c) Serial number
d) Digital Signature of issuer - answer a) Version