WGU D830 INTRODUCTION TO
CRYPTOGRAPHY OA PRACTICE
QUESTIONS AND ANSWERS |
LATEST MOCK PRACTICE SET
140 Questions with Answers and Detailed Rationales
100 PERCENT GUARANTEED PASS
INSTANT DOWNLOAD ANSWERS INCLUDED
IMPORTANCE OF THIS DOCUMENT
This comprehensive examination preparation guide has been meticulously developed to help you succeed in the
WGU D830 INTRODUCTION TO CRYPTOGRAPHY OA PRACTICE QUESTIONS AND ANSWERS |
COMPLETE EXAM PREP 2026 | 100% CORRECT. It contains 140 carefully selected questions that reflect the
most current exam content and testing strategies. Each question is accompanied by a correct answer and a
detailed rationale that explains the underlying pathophysiology, pharmacology, or clinical reasoning.
Self-Assessment – Test your knowledge and Exam Preparation – Familiarize yourself with the
identify areas requiring further question format and content
study areas
Concept Reinforcement – Deepen your Confidence Building – Develop test-taking
understanding through strategies and reduce
evidence-based exam anxiety
rationales
Time Management – Practice answering
questions under simulated
exam conditions
Review Summary 140 Questions
Foundations - Application - WGU D830 Introduction TO Cryptography OA AND Complete PREP 2026 100
Correct Cryptography Undergraduate YEAR 3 / Graduate
All answers with rationales
,Table of Contents
Content Area Questions Key Topics
Foundations OF 1-24 Security, Primary, Cipher, Signature, Attacker
Cryptography
Symmetric Cryptography 25-48 Security, Attacker, Property, Primary, System
Asymmetric Cryptography 49-72 Attacker, Curve, Elliptic, Problem, Cipher
HASH Functions AND Digital 73-96 Attack, Context, Security, Primary, Curve
Signatures
KEY Management AND 97-120 Attack, Block, Cipher, Security, Signature
Distribution
Cryptographic Protocols 121-140 Attacker, Function, Public, Exponent, Modulus
AND Applications
TOTAL 140 All questions include answers and detailed rationales
,Section A - Foundations OF Cryptography
Q1.
In a Feistel cipher, the round function F is applied to one half of the block, and the result
is XORed with the other half. If F is cryptographically weak (e.g., linear), which property of
the overall cipher is most directly compromised?
A. Key schedule strength B. Confusion and diffusion
C. Block size D. Number of rounds
Correct: B - Confusion and diffusion
Rationale:The round function F is responsible for providing confusion and diffusion. If F is
linear, the cipher becomes vulnerable to linear cryptanalysis, compromising these essential
properties. Key schedule, block size, and number of rounds are separate design aspects,
though they may interact.
Q2.
An elliptic curve group over a finite field has order n. For a point G of prime order q, what
is the relationship between the cofactor h and the security of the discrete logarithm
problem?
A. Larger h reduces security by making the B. Smaller h increases the likelihood of a
group easier to embed into a finite field. Pohlig-Hellman attack.
C. The cofactor h must be 1 to ensure the D. The cofactor h affects the efficiency of
group is cyclic and secure. point multiplication but not security.
Correct: A - Larger h reduces security by making the group easier to embed into a finite
field.
Rationale:A large cofactor h means the group order has a large composite factor, which may
allow embedding attacks (MOV attack) or reduce the effective security level. The cofactor
should be small (typically 1, 2, or 4) to avoid these issues. Pohlig-Hellman is mitigated by
having a large prime factor, not by small h. Efficiency is not the primary security concern.
Q3.
In RSA, given p=61, q=53, and e=17, what is the private exponent d?
A. 413 B. 2753
C. 3120 D. 17
Correct: B - 2753
Page 3
, Section A - Foundations OF Cryptography
Rationale: n = p*q = 61*53 = 3233. Æ(n) = (p-1)(q-1) = 60*52 = 3120. d is the modular inverse
of e mod (n): 17*d 1 mod 3120. The inverse is 2753, since 17*2753 = 46801 = 15*3120 + 1.
Q4.
Which of the following best describes the security goal of a cryptographic hash function's
preimage resistance?
A. Given a hash value, it is computationally B. Given an input, it is computationally
infeasible to find any input that hashes to infeasible to find a different input with the
that value. same hash.
C. It is computationally infeasible to find two D. The hash function produces a fixed-size
different inputs with the same hash. output regardless of input size.
Correct: A - Given a hash value, it is computationally infeasible to find any input that
hashes to that value.
Rationale:Preimage resistance means that for a given output y, it is hard to find any input x
such that H(x)=y. Option B describes second preimage resistance, C describes collision
resistance, and D is a property of hash functions but not a security goal.
Q5.
In a digital signature scheme based on elliptic curves (ECDSA), the nonce k must be
unique and unpredictable per signature. If an attacker obtains two signatures that used
the same k, what can they recover?
A. The message hashes of both signatures B. The private key
C. The public key D. The curve parameters
Correct: B - The private key
Rationale:If the same k is used for two different messages, the private key can be recovered
algebraically. Given two signatures (r,s1) and (r,s2) with same r, the attacker can compute k =
(z1 - z2)/(s1 - s2) mod n, then derive the private key d = (s1*k - z1)/r mod n. This is a known
vulnerability.
Q6.
Which of the following is a primary advantage of using authenticated encryption (e.g.,
AES-GCM) over separate encryption and MAC operations?
A. It provides confidentiality only, which is B. It is always faster than any other mode.
sufficient for most applications.
C. It simplifies key management by using a D. It prevents chosen-ciphertext attacks by
single key. ensuring ciphertext integrity.
Page 4
CRYPTOGRAPHY OA PRACTICE
QUESTIONS AND ANSWERS |
LATEST MOCK PRACTICE SET
140 Questions with Answers and Detailed Rationales
100 PERCENT GUARANTEED PASS
INSTANT DOWNLOAD ANSWERS INCLUDED
IMPORTANCE OF THIS DOCUMENT
This comprehensive examination preparation guide has been meticulously developed to help you succeed in the
WGU D830 INTRODUCTION TO CRYPTOGRAPHY OA PRACTICE QUESTIONS AND ANSWERS |
COMPLETE EXAM PREP 2026 | 100% CORRECT. It contains 140 carefully selected questions that reflect the
most current exam content and testing strategies. Each question is accompanied by a correct answer and a
detailed rationale that explains the underlying pathophysiology, pharmacology, or clinical reasoning.
Self-Assessment – Test your knowledge and Exam Preparation – Familiarize yourself with the
identify areas requiring further question format and content
study areas
Concept Reinforcement – Deepen your Confidence Building – Develop test-taking
understanding through strategies and reduce
evidence-based exam anxiety
rationales
Time Management – Practice answering
questions under simulated
exam conditions
Review Summary 140 Questions
Foundations - Application - WGU D830 Introduction TO Cryptography OA AND Complete PREP 2026 100
Correct Cryptography Undergraduate YEAR 3 / Graduate
All answers with rationales
,Table of Contents
Content Area Questions Key Topics
Foundations OF 1-24 Security, Primary, Cipher, Signature, Attacker
Cryptography
Symmetric Cryptography 25-48 Security, Attacker, Property, Primary, System
Asymmetric Cryptography 49-72 Attacker, Curve, Elliptic, Problem, Cipher
HASH Functions AND Digital 73-96 Attack, Context, Security, Primary, Curve
Signatures
KEY Management AND 97-120 Attack, Block, Cipher, Security, Signature
Distribution
Cryptographic Protocols 121-140 Attacker, Function, Public, Exponent, Modulus
AND Applications
TOTAL 140 All questions include answers and detailed rationales
,Section A - Foundations OF Cryptography
Q1.
In a Feistel cipher, the round function F is applied to one half of the block, and the result
is XORed with the other half. If F is cryptographically weak (e.g., linear), which property of
the overall cipher is most directly compromised?
A. Key schedule strength B. Confusion and diffusion
C. Block size D. Number of rounds
Correct: B - Confusion and diffusion
Rationale:The round function F is responsible for providing confusion and diffusion. If F is
linear, the cipher becomes vulnerable to linear cryptanalysis, compromising these essential
properties. Key schedule, block size, and number of rounds are separate design aspects,
though they may interact.
Q2.
An elliptic curve group over a finite field has order n. For a point G of prime order q, what
is the relationship between the cofactor h and the security of the discrete logarithm
problem?
A. Larger h reduces security by making the B. Smaller h increases the likelihood of a
group easier to embed into a finite field. Pohlig-Hellman attack.
C. The cofactor h must be 1 to ensure the D. The cofactor h affects the efficiency of
group is cyclic and secure. point multiplication but not security.
Correct: A - Larger h reduces security by making the group easier to embed into a finite
field.
Rationale:A large cofactor h means the group order has a large composite factor, which may
allow embedding attacks (MOV attack) or reduce the effective security level. The cofactor
should be small (typically 1, 2, or 4) to avoid these issues. Pohlig-Hellman is mitigated by
having a large prime factor, not by small h. Efficiency is not the primary security concern.
Q3.
In RSA, given p=61, q=53, and e=17, what is the private exponent d?
A. 413 B. 2753
C. 3120 D. 17
Correct: B - 2753
Page 3
, Section A - Foundations OF Cryptography
Rationale: n = p*q = 61*53 = 3233. Æ(n) = (p-1)(q-1) = 60*52 = 3120. d is the modular inverse
of e mod (n): 17*d 1 mod 3120. The inverse is 2753, since 17*2753 = 46801 = 15*3120 + 1.
Q4.
Which of the following best describes the security goal of a cryptographic hash function's
preimage resistance?
A. Given a hash value, it is computationally B. Given an input, it is computationally
infeasible to find any input that hashes to infeasible to find a different input with the
that value. same hash.
C. It is computationally infeasible to find two D. The hash function produces a fixed-size
different inputs with the same hash. output regardless of input size.
Correct: A - Given a hash value, it is computationally infeasible to find any input that
hashes to that value.
Rationale:Preimage resistance means that for a given output y, it is hard to find any input x
such that H(x)=y. Option B describes second preimage resistance, C describes collision
resistance, and D is a property of hash functions but not a security goal.
Q5.
In a digital signature scheme based on elliptic curves (ECDSA), the nonce k must be
unique and unpredictable per signature. If an attacker obtains two signatures that used
the same k, what can they recover?
A. The message hashes of both signatures B. The private key
C. The public key D. The curve parameters
Correct: B - The private key
Rationale:If the same k is used for two different messages, the private key can be recovered
algebraically. Given two signatures (r,s1) and (r,s2) with same r, the attacker can compute k =
(z1 - z2)/(s1 - s2) mod n, then derive the private key d = (s1*k - z1)/r mod n. This is a known
vulnerability.
Q6.
Which of the following is a primary advantage of using authenticated encryption (e.g.,
AES-GCM) over separate encryption and MAC operations?
A. It provides confidentiality only, which is B. It is always faster than any other mode.
sufficient for most applications.
C. It simplifies key management by using a D. It prevents chosen-ciphertext attacks by
single key. ensuring ciphertext integrity.
Page 4
