WGU D334 PA INTRO TO CRYPTOGRAPHY
QUESTIONS AND CORRECT ANSWERS PLUS
RATIONALE LATEST 2026-2027 UPDATE
50 QUESTIONS
TABLE OF CONTENTS
# TOPIC
1 Analyze and differentiate symmetric and asymmetric cryptographic algorithms based on security
properties and use cases
2 Evaluate the security of cryptographic systems by identifying vulnerabilities, attack vectors, and
appropriate countermeasures
3 Apply cryptographic primitives such as hash functions, digital signatures, and key exchange protocols to
design secure communication solutions
4 WGU D334 PA Intro to Cryptography Questions and Correct Answers Plus Rationale Latest 2026
5 2027 Update
6 Foundations of Cryptography and Information Security
7 Applied Cryptography and Information Security
8 Advanced Cryptography and Information Security
9 Cryptography and Information Security Review
ABSTRACT
This study document brings together 50 carefully worded exam questions drawn from WGU D334
PA Intro to Cryptography Questions and Correct Answers Plus Rationale Latest 2026-2027
Update, with the strongest emphasis placed on Analyze and differentiate symmetric and
asymmetric cryptographic algorithms based on security properties and use cases, Evaluate the
security of cryptographic systems by identifying vulnerabilities, attack vectors, and appropriate
countermeasures, Apply cryptographic primitives such as hash functions, digital signatures and
and key exchange protocols to design secure communication solutions. Every item follows the
wording style and level of reasoning you meet in the real paper, and each one is paired with a clear
rationale so the correct choice is never a guess. Work through the set at your own pace, mark the
questions that slow you down, then come back to them until the reasoning feels automatic.
Learners who revise this way walk into the exam room recognising the pattern behind the
questions instead of meeting them for the first time. Keep going - steady, honest practice is what
turns a difficult paper into a comfortable pass.
Page 1
,Q1 ANALYZE AND DIFFERENTIATE SYMMETRIC AND ASYMMETRIC CRYPTOGRAPHIC
ALGORITHMS BASED ON SECURITY PROPERTIES AND USE CASES
A security architect must choose between AES-256 in Galois/Counter Mode (GCM)
and AES-256 in Cipher Block Chaining (CBC) mode for encrypting a high-volume,
low-latency network stream. Which property of GCM makes it the superior choice
in this scenario?
A. GCM provides authenticated encryption, ensuring both confidentiality and integrity without a
separate MAC. CORRECT
B. GCM uses a 256-bit block size, whereas CBC uses 128-bit blocks, offering stronger diffusion.
C. GCM is resistant to side-channel attacks due to its use of table-based S-boxes.
D. GCM requires no initialization vector (IV), simplifying key management.
RATIONALE: GCM is an authenticated encryption mode that combines CTR mode encryption
with GHASH for authentication, providing confidentiality and integrity in one pass. CBC requires a
separate MAC for integrity and is vulnerable to padding oracle attacks if not implemented
carefully. Options B, C, and D are factually incorrect: AES has a fixed 128-bit block size, GCM
may be vulnerable to cache-timing attacks, and GCM requires a unique IV.
Q2 ANALYZE AND DIFFERENTIATE SYMMETRIC AND ASYMMETRIC CRYPTOGRAPHIC
ALGORITHMS BASED ON SECURITY PROPERTIES AND USE CASES
In the context of public-key infrastructure (PKI), what is the primary security
concern if a Certificate Authority (CA) issues a certificate without properly
verifying the applicant's identity?
A. It enables an attacker to impersonate the legitimate entity, undermining trust in all certificates
issued by that CA. CORRECT
B. It allows the attacker to decrypt all past communications encrypted with the CA's public key.
C. It causes the CA's private key to be exposed, leading to a complete collapse of the PKI.
D. It forces the use of weaker cryptographic algorithms in the certificate to maintain compatibility.
RATIONALE: Improper identity verification allows an attacker to obtain a certificate for a domain
they do not control, enabling impersonation and man-in-the-middle attacks. This erodes trust in
the CA and can lead to revocation or distrust by browsers. Options B, C, and D are incorrect
because certificate issuance does not expose the CA's private key, does not affect past session
keys, and does not dictate algorithm strength.
Page 2
, Q3 ANALYZE AND DIFFERENTIATE SYMMETRIC AND ASYMMETRIC CRYPTOGRAPHIC
ALGORITHMS BASED ON SECURITY PROPERTIES AND USE CASES
Which of the following best explains why hash functions like SHA-256 are
considered collision-resistant but not perfectly collision-free?
A. The pigeonhole principle guarantees that collisions exist because the input space is larger
than the output space. CORRECT
B. SHA-256 uses a Merkle-Damgård construction that is provably collision-free.
C. Collisions are only theoretical and cannot be found even with infinite computing power.
D. SHA-256's output length is 256 bits, which is too short to avoid collisions in practice.
RATIONALE: Because SHA-256 maps arbitrary-length inputs to a fixed 256-bit output, the
number of possible inputs exceeds the number of outputs, so collisions must exist by the
pigeonhole principle. However, finding them is computationally infeasible, which is the basis for
collision resistance. Options B, C, and D are incorrect: Merkle-Damgård does not guarantee
collision-freeness, collisions are not merely theoretical, and 256-bit outputs are considered
secure against brute-force collisions.
Q4 ANALYZE AND DIFFERENTIATE SYMMETRIC AND ASYMMETRIC CRYPTOGRAPHIC
ALGORITHMS BASED ON SECURITY PROPERTIES AND USE CASES
A developer implements RSA encryption with a 1024-bit modulus and PKCS#1 v1.5
padding. Which vulnerability is most likely to be exploitable in this configuration?
A. Bleichenbacher's attack, which exploits the padding oracle to decrypt ciphertexts.
CORRECT
B. Pollard's rho algorithm for factoring the modulus in polynomial time.
C. Shor's algorithm running on a classical computer to factor the modulus.
D. The birthday attack, which finds collisions in the RSA padding scheme.
RATIONALE: PKCS#1 v1.5 padding is susceptible to Bleichenbacher's adaptive
chosen-ciphertext attack, which leverages padding error messages to gradually decrypt
ciphertexts. A 1024-bit modulus is also considered weak but is not directly broken by Pollard's
rho in feasible time. Shor's algorithm requires a quantum computer, and birthday attacks target
hash functions, not RSA padding.
Page 3
QUESTIONS AND CORRECT ANSWERS PLUS
RATIONALE LATEST 2026-2027 UPDATE
50 QUESTIONS
TABLE OF CONTENTS
# TOPIC
1 Analyze and differentiate symmetric and asymmetric cryptographic algorithms based on security
properties and use cases
2 Evaluate the security of cryptographic systems by identifying vulnerabilities, attack vectors, and
appropriate countermeasures
3 Apply cryptographic primitives such as hash functions, digital signatures, and key exchange protocols to
design secure communication solutions
4 WGU D334 PA Intro to Cryptography Questions and Correct Answers Plus Rationale Latest 2026
5 2027 Update
6 Foundations of Cryptography and Information Security
7 Applied Cryptography and Information Security
8 Advanced Cryptography and Information Security
9 Cryptography and Information Security Review
ABSTRACT
This study document brings together 50 carefully worded exam questions drawn from WGU D334
PA Intro to Cryptography Questions and Correct Answers Plus Rationale Latest 2026-2027
Update, with the strongest emphasis placed on Analyze and differentiate symmetric and
asymmetric cryptographic algorithms based on security properties and use cases, Evaluate the
security of cryptographic systems by identifying vulnerabilities, attack vectors, and appropriate
countermeasures, Apply cryptographic primitives such as hash functions, digital signatures and
and key exchange protocols to design secure communication solutions. Every item follows the
wording style and level of reasoning you meet in the real paper, and each one is paired with a clear
rationale so the correct choice is never a guess. Work through the set at your own pace, mark the
questions that slow you down, then come back to them until the reasoning feels automatic.
Learners who revise this way walk into the exam room recognising the pattern behind the
questions instead of meeting them for the first time. Keep going - steady, honest practice is what
turns a difficult paper into a comfortable pass.
Page 1
,Q1 ANALYZE AND DIFFERENTIATE SYMMETRIC AND ASYMMETRIC CRYPTOGRAPHIC
ALGORITHMS BASED ON SECURITY PROPERTIES AND USE CASES
A security architect must choose between AES-256 in Galois/Counter Mode (GCM)
and AES-256 in Cipher Block Chaining (CBC) mode for encrypting a high-volume,
low-latency network stream. Which property of GCM makes it the superior choice
in this scenario?
A. GCM provides authenticated encryption, ensuring both confidentiality and integrity without a
separate MAC. CORRECT
B. GCM uses a 256-bit block size, whereas CBC uses 128-bit blocks, offering stronger diffusion.
C. GCM is resistant to side-channel attacks due to its use of table-based S-boxes.
D. GCM requires no initialization vector (IV), simplifying key management.
RATIONALE: GCM is an authenticated encryption mode that combines CTR mode encryption
with GHASH for authentication, providing confidentiality and integrity in one pass. CBC requires a
separate MAC for integrity and is vulnerable to padding oracle attacks if not implemented
carefully. Options B, C, and D are factually incorrect: AES has a fixed 128-bit block size, GCM
may be vulnerable to cache-timing attacks, and GCM requires a unique IV.
Q2 ANALYZE AND DIFFERENTIATE SYMMETRIC AND ASYMMETRIC CRYPTOGRAPHIC
ALGORITHMS BASED ON SECURITY PROPERTIES AND USE CASES
In the context of public-key infrastructure (PKI), what is the primary security
concern if a Certificate Authority (CA) issues a certificate without properly
verifying the applicant's identity?
A. It enables an attacker to impersonate the legitimate entity, undermining trust in all certificates
issued by that CA. CORRECT
B. It allows the attacker to decrypt all past communications encrypted with the CA's public key.
C. It causes the CA's private key to be exposed, leading to a complete collapse of the PKI.
D. It forces the use of weaker cryptographic algorithms in the certificate to maintain compatibility.
RATIONALE: Improper identity verification allows an attacker to obtain a certificate for a domain
they do not control, enabling impersonation and man-in-the-middle attacks. This erodes trust in
the CA and can lead to revocation or distrust by browsers. Options B, C, and D are incorrect
because certificate issuance does not expose the CA's private key, does not affect past session
keys, and does not dictate algorithm strength.
Page 2
, Q3 ANALYZE AND DIFFERENTIATE SYMMETRIC AND ASYMMETRIC CRYPTOGRAPHIC
ALGORITHMS BASED ON SECURITY PROPERTIES AND USE CASES
Which of the following best explains why hash functions like SHA-256 are
considered collision-resistant but not perfectly collision-free?
A. The pigeonhole principle guarantees that collisions exist because the input space is larger
than the output space. CORRECT
B. SHA-256 uses a Merkle-Damgård construction that is provably collision-free.
C. Collisions are only theoretical and cannot be found even with infinite computing power.
D. SHA-256's output length is 256 bits, which is too short to avoid collisions in practice.
RATIONALE: Because SHA-256 maps arbitrary-length inputs to a fixed 256-bit output, the
number of possible inputs exceeds the number of outputs, so collisions must exist by the
pigeonhole principle. However, finding them is computationally infeasible, which is the basis for
collision resistance. Options B, C, and D are incorrect: Merkle-Damgård does not guarantee
collision-freeness, collisions are not merely theoretical, and 256-bit outputs are considered
secure against brute-force collisions.
Q4 ANALYZE AND DIFFERENTIATE SYMMETRIC AND ASYMMETRIC CRYPTOGRAPHIC
ALGORITHMS BASED ON SECURITY PROPERTIES AND USE CASES
A developer implements RSA encryption with a 1024-bit modulus and PKCS#1 v1.5
padding. Which vulnerability is most likely to be exploitable in this configuration?
A. Bleichenbacher's attack, which exploits the padding oracle to decrypt ciphertexts.
CORRECT
B. Pollard's rho algorithm for factoring the modulus in polynomial time.
C. Shor's algorithm running on a classical computer to factor the modulus.
D. The birthday attack, which finds collisions in the RSA padding scheme.
RATIONALE: PKCS#1 v1.5 padding is susceptible to Bleichenbacher's adaptive
chosen-ciphertext attack, which leverages padding error messages to gradually decrypt
ciphertexts. A 1024-bit modulus is also considered weak but is not directly broken by Pollard's
rho in feasible time. Shor's algorithm requires a quantum computer, and birthday attacks target
hash functions, not RSA padding.
Page 3
