WGU D830 Introduction to
Cryptography Comprehensive OA
Practice Exam Questions with
Detailed Rationales & Expert
Explanations Complete 2026 Exam
Preparation Guide
QUESTION 1
A security administrator needs to verify that a software update has not
been altered during download. Which cryptographic method should
be used?
A) Asymmetric encryption
B) Digital signature
C) Cryptographic hash function
D) Symmetric encryption
Answer: C
Rationale: By comparing the hash of the downloaded file with the original
hash provided by the vendor, the administrator can verify file integrity.
Hash functions produce a fixed-length output that changes dramatically if
even one bit of the original file changes, making them ideal for integrity
verification .
QUESTION 2
,Which component of a Public Key Infrastructure (PKI) is responsible
for issuing digital certificates?
A) Registration Authority (RA)
B) Certificate Authority (CA)
C) Certificate Revocation List (CRL)
D) Online Certificate Status Protocol (OCSP)
Answer: B
Rationale: The Certificate Authority (CA) is the trusted entity that issues
and validates digital certificates. The RA verifies identities before certificates
are issued, CRLs list revoked certificates, and OCSP provides real-time
revocation status checking .
QUESTION 3
What is the effective security strength of 3DES when using three 56-bit
keys?
A) 56 bits
B) 168 bits
C) 112 bits
D) 256 bits
Answer: C
Rationale: While 3DES uses three 56-bit keys (totaling 168 bits), the
effective security is only 112 bits due to meet-in-the-middle attacks that
reduce the computational complexity required to break the encryption .
QUESTION 4
,Which algorithm is typically used to generate the thumbprint of a
certificate?
A) RSA
B) 3DES
C) AES
D) SHA-1
Answer: D
Rationale: The thumbprint of a certificate is a hash value used for unique
identification. It is typically generated using a one-way hashing algorithm,
commonly SHA-1, though newer systems are moving to stronger hashes.
SHA-1 produces a 160-bit message digest .
QUESTION 5
Which block cipher mode encrypts each group with the same key,
leaving each group independent of the others?
A) ECB
B) CBC
C) CFB
D) OFB
Answer: A
Rationale: Electronic Codebook (ECB) mode encrypts each block
independently using the same key. Identical plaintext blocks produce
identical ciphertext, revealing patterns and making it insecure for most
applications where data has repeating patterns .
QUESTION 6
, What is the output length of an MD5 hash?
A) 32 bits
B) 64 bits
C) 128 bits
D) 256 bits
Answer: C
Rationale: MD5 (Message Digest 5) always produces a 128-bit hash value,
typically displayed as a 32-character hexadecimal string, regardless of the
input size .
QUESTION 7
What is the output length of a SHA-1 hash?
A) 128 bits
B) 160 bits
C) 256 bits
D) 512 bits
Answer: B
Rationale: SHA-1 produces a fixed 160-bit message digest. It has been
officially retired from secure use due to practical collision demonstration
exploits .
QUESTION 8
Which vulnerability is the basic Diffie-Hellman key exchange
susceptible to?
Cryptography Comprehensive OA
Practice Exam Questions with
Detailed Rationales & Expert
Explanations Complete 2026 Exam
Preparation Guide
QUESTION 1
A security administrator needs to verify that a software update has not
been altered during download. Which cryptographic method should
be used?
A) Asymmetric encryption
B) Digital signature
C) Cryptographic hash function
D) Symmetric encryption
Answer: C
Rationale: By comparing the hash of the downloaded file with the original
hash provided by the vendor, the administrator can verify file integrity.
Hash functions produce a fixed-length output that changes dramatically if
even one bit of the original file changes, making them ideal for integrity
verification .
QUESTION 2
,Which component of a Public Key Infrastructure (PKI) is responsible
for issuing digital certificates?
A) Registration Authority (RA)
B) Certificate Authority (CA)
C) Certificate Revocation List (CRL)
D) Online Certificate Status Protocol (OCSP)
Answer: B
Rationale: The Certificate Authority (CA) is the trusted entity that issues
and validates digital certificates. The RA verifies identities before certificates
are issued, CRLs list revoked certificates, and OCSP provides real-time
revocation status checking .
QUESTION 3
What is the effective security strength of 3DES when using three 56-bit
keys?
A) 56 bits
B) 168 bits
C) 112 bits
D) 256 bits
Answer: C
Rationale: While 3DES uses three 56-bit keys (totaling 168 bits), the
effective security is only 112 bits due to meet-in-the-middle attacks that
reduce the computational complexity required to break the encryption .
QUESTION 4
,Which algorithm is typically used to generate the thumbprint of a
certificate?
A) RSA
B) 3DES
C) AES
D) SHA-1
Answer: D
Rationale: The thumbprint of a certificate is a hash value used for unique
identification. It is typically generated using a one-way hashing algorithm,
commonly SHA-1, though newer systems are moving to stronger hashes.
SHA-1 produces a 160-bit message digest .
QUESTION 5
Which block cipher mode encrypts each group with the same key,
leaving each group independent of the others?
A) ECB
B) CBC
C) CFB
D) OFB
Answer: A
Rationale: Electronic Codebook (ECB) mode encrypts each block
independently using the same key. Identical plaintext blocks produce
identical ciphertext, revealing patterns and making it insecure for most
applications where data has repeating patterns .
QUESTION 6
, What is the output length of an MD5 hash?
A) 32 bits
B) 64 bits
C) 128 bits
D) 256 bits
Answer: C
Rationale: MD5 (Message Digest 5) always produces a 128-bit hash value,
typically displayed as a 32-character hexadecimal string, regardless of the
input size .
QUESTION 7
What is the output length of a SHA-1 hash?
A) 128 bits
B) 160 bits
C) 256 bits
D) 512 bits
Answer: B
Rationale: SHA-1 produces a fixed 160-bit message digest. It has been
officially retired from secure use due to practical collision demonstration
exploits .
QUESTION 8
Which vulnerability is the basic Diffie-Hellman key exchange
susceptible to?
