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WGU C839 OBJECTIVE ASSESSMENT FINAL/WGU C839
INTRODUCTION TO CRYPTOGRAPHY NEWEST 2026 ACTUAL EXAM
WITH COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS
(100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR
VERIFIED||
Don't ever trust a ____________ or ________________.
(Kerckhoffs's Principle) - ANSWER-secret block cipher; secret
algorithm
A protocol for online shopping with a credit card. One of its
features is that it encrypts the credit card number so that an
eavesdropper cannot copy it. - ANSWER-SET
_______________ is the worst enemy of security, and it almost
always comes in the form of features or options. - ANSWER-
Complexity
______________ is a measure of how many things interact at any
one point. If the effect of an option is limited to a small part of the
program, then it cannot interact with an option whose effect is
limited to another part of the program. - ANSWER-Complexity
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The original message, m is called the ______________. -
ANSWER-plaintext
The public-key algorithms are used to establish _________,
which in turn is used to encrypt the actual data. This combines the
flexibility of public-key cryptography with the efficiency of
symmetric-key cryptography. - ANSWER-a secret key
Digital signatures are the public-key equivalent of
______________________. - ANSWER-message authentication
codes
For practical reasons, a PKI is often set up with multiple levels of
CAs. There is a top-level CA, called the ________, which issues
certificates on the keys of lower-level CAs, which in turn certify
the user keys. - ANSWER-root
A ____________________ is what most people mean when
talking about breaking an encryption system. This is the situation
in which Alice and Bob are encrypting their data, and all you as
the attacker get to see is the ciphertext. Trying to decrypt a
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message if you only know the ciphertext is called a ciphertext-only
attack. This is the most difficult type of attack, because you have
the least amount of information. - ANSWER-ciphertext-only attack
A ________________ is one in which you know both the plaintext
and the ciphertext. The most obvious goal is to find the decryption
key. - ANSWER-known-plaintext attack
A known-plaintext attack is more powerful than a ciphertext-only
attack.
A True
B False - ANSWER-A
A __________________ is any nontrivial method that detects a
difference between the ideal encryption scheme and the actual
one. This covers all the attacks we have discussed so far, as well
as any yet-to-be-discovered attacks. - ANSWER-distinguishing
attack
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A ____________________is an attack that depends on the fact
that duplicate values, also called collisions, appear much faster
than you would expect. - ANSWER-Birthday attack
An __________________ attack is one that tries all possible
values for some target object, like the key. If an attack requires
2^235 steps of work, then this corresponds to an exhaustive
search for a 235-bit value. - ANSWER-exhaustive search
First introduced by Eli Biham in 1993, a ___________ attack
assumes that the attacker has access to several encryption
functions. These functions all have an unknown key, but their
keys have a relationship that the attacker knows. - ANSWER-
related-key
A _____________ cipher is one for which no attack exists. -
ANSWER-secure block
An attack on a block cipher is a non-generic method of
distinguishing the block cipher from an ______________ cipher. -
ANSWER-ideal block
WGU C839 OBJECTIVE ASSESSMENT FINAL/WGU C839
INTRODUCTION TO CRYPTOGRAPHY NEWEST 2026 ACTUAL EXAM
WITH COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS
(100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR
VERIFIED||
Don't ever trust a ____________ or ________________.
(Kerckhoffs's Principle) - ANSWER-secret block cipher; secret
algorithm
A protocol for online shopping with a credit card. One of its
features is that it encrypts the credit card number so that an
eavesdropper cannot copy it. - ANSWER-SET
_______________ is the worst enemy of security, and it almost
always comes in the form of features or options. - ANSWER-
Complexity
______________ is a measure of how many things interact at any
one point. If the effect of an option is limited to a small part of the
program, then it cannot interact with an option whose effect is
limited to another part of the program. - ANSWER-Complexity
,2|Page
The original message, m is called the ______________. -
ANSWER-plaintext
The public-key algorithms are used to establish _________,
which in turn is used to encrypt the actual data. This combines the
flexibility of public-key cryptography with the efficiency of
symmetric-key cryptography. - ANSWER-a secret key
Digital signatures are the public-key equivalent of
______________________. - ANSWER-message authentication
codes
For practical reasons, a PKI is often set up with multiple levels of
CAs. There is a top-level CA, called the ________, which issues
certificates on the keys of lower-level CAs, which in turn certify
the user keys. - ANSWER-root
A ____________________ is what most people mean when
talking about breaking an encryption system. This is the situation
in which Alice and Bob are encrypting their data, and all you as
the attacker get to see is the ciphertext. Trying to decrypt a
,3|Page
message if you only know the ciphertext is called a ciphertext-only
attack. This is the most difficult type of attack, because you have
the least amount of information. - ANSWER-ciphertext-only attack
A ________________ is one in which you know both the plaintext
and the ciphertext. The most obvious goal is to find the decryption
key. - ANSWER-known-plaintext attack
A known-plaintext attack is more powerful than a ciphertext-only
attack.
A True
B False - ANSWER-A
A __________________ is any nontrivial method that detects a
difference between the ideal encryption scheme and the actual
one. This covers all the attacks we have discussed so far, as well
as any yet-to-be-discovered attacks. - ANSWER-distinguishing
attack
, 4|Page
A ____________________is an attack that depends on the fact
that duplicate values, also called collisions, appear much faster
than you would expect. - ANSWER-Birthday attack
An __________________ attack is one that tries all possible
values for some target object, like the key. If an attack requires
2^235 steps of work, then this corresponds to an exhaustive
search for a 235-bit value. - ANSWER-exhaustive search
First introduced by Eli Biham in 1993, a ___________ attack
assumes that the attacker has access to several encryption
functions. These functions all have an unknown key, but their
keys have a relationship that the attacker knows. - ANSWER-
related-key
A _____________ cipher is one for which no attack exists. -
ANSWER-secure block
An attack on a block cipher is a non-generic method of
distinguishing the block cipher from an ______________ cipher. -
ANSWER-ideal block
