WGU C839 OA EXAM 100+ REAL EXAM QUESTIONS
AND CORRECT VERIFIED ANSWERS)|AGRADE 2025
Which encryption standard uses the same key to encrypt and decrypt messages? - ANSWER-
Symmetric
Which algorithm is designated as a Type 2 product by the National Security Agency (NSA)? - ANSWER-
Skipjack
What is the most commonly used format for certificates? - ANSWER-X.509 v3
What is referenced to determine if a certificate has been revoked? - ANSWER-Certificate revocation
list (CRL)
What needs to be installed on end users' computers to allow them to trust applications that have
been digitally signed by the developer? - ANSWER-Sender's public key
Which type of certificate must be certified by an authority to verify it with other participants? -
ANSWER-Public Certificate
What is an attribute of the Rivest Cipher 4 (RC4) algorithm? - ANSWER-It requires a unique nonce.
Which mode generates the key stream with a nonce and incrementing value? - ANSWER-Counter (CTR)
Which mode is a stream algorithm that concatenates an incrementing value with a nonce? - ANSWER-
Counter (CTR)
Which key would an administrator use to encrypt data so only the CEO can decrypt it? - ANSWER-
CEO's public key
What is the result of a hash function? - ANSWER-Digest
What is used to efficiently encrypt large files? - ANSWER-Symmetric encryption
An administrator needs to encrypt the following word with the Atbash cipher: security What is the
correct ciphertext? - ANSWER-hvxfirgb
Which cryptographic algorithm has a 128-bit hash size? - ANSWER-Message Digest Algorithm 5 (MD5)
Which characteristic makes a hashing function suitable for use in signature schemes? - ANSWER-
Collision resistance
Which attribute of a hashing function makes a birthday attack possible? - ANSWER-Partial-message
collision
Which hash algorithm produces a 160-bit output value? - ANSWER-SHA-1
What does cipher block chaining (CBC) use with the key to encrypt subsequent blocks of plaintext? -
ANSWER-Previous generated ciphertext
Which mode produces the same ciphertext from two identical plaintext blocks? - ANSWER-Electronic
codebook (ECB)
, Which encryption mode is least secure? - ANSWER-Electronic codebook (ECB)
What is the mathematical formula used for symmetric decryption? - ANSWER-P = E (K,C)
Which algorithm relies on factoring the product of large prime numbers? - ANSWER-Rivest-Shamir-
Adleman
Which encryption technology is a serial combination of hashing, data compression, symmetric-key
cryptography, and public key infrastructure (PKI) and can be used for encrypting texts, emails, files,
and directories or for full disk encryption? - ANSWER-Pretty Good Privacy (PGP)
Which concept stipulates that algorithms should be openly shared and scrutinized, but keys must be
absolutely secured? - ANSWER-Kerckhoffs's principle
Which encryption process minimizes known plaintext attacks against Advanced Encryption Standard
(AES)? - ANSWER-Randomizing the initialization vector
What prevents a rainbow table attack during the encryption process? - ANSWER-Salting
Which factor increases the required number of attempts in a brute-force attack? - ANSWER-Larger
key size
What is a vulnerability of the Data Encryption Standard (DES)? - ANSWER-Key length is too short.
Which block size does the Advanced Encryption Standard (AES) use? - ANSWER-128
Which block algorithm includes a provision for the decryption key kept in a key escrow? - ANSWER-
Skipjack
What is the result of A|B and B|C? - ANSWER-A|C
How is X mod N if N = PQ represented in number theory? - ANSWER-( X mod P, X mod Q)
What is the outcome when using the binary AND function on 11011 and 10100? - ANSWER-10000
Which mode does the Fortuna algorithm use to generate random numbers? - ANSWER-Counter (CTR)
What is a potential weakness of a pseudo-random number generator (PRNG)? - ANSWER-Same state
used more than once
Which key combination is used to decrypt and verify a digital signature? - ANSWER-Recipient's private
key to decrypt and sender's public key to verify the signature
Which key is used to sign a message or a message digest? - ANSWER-Sender's private key
Which key does the certificate authority (CA) use to digitally sign keys that it issues? - ANSWER-
Server's private key
What does an end user need to verify a Rivest-Shamir -Adleman (RSA) digitally signed message? -
ANSWER-Sender's public key
What is used when creating a digital signature, using public key infrastructure (PKI)? - ANSWER-The
private key of the person creating the message
Which feature in Wired Equivalent Privacy (WEP) provides integrity control when sending packets
over a wireless network? - ANSWER-Cyclic redundancy check
AND CORRECT VERIFIED ANSWERS)|AGRADE 2025
Which encryption standard uses the same key to encrypt and decrypt messages? - ANSWER-
Symmetric
Which algorithm is designated as a Type 2 product by the National Security Agency (NSA)? - ANSWER-
Skipjack
What is the most commonly used format for certificates? - ANSWER-X.509 v3
What is referenced to determine if a certificate has been revoked? - ANSWER-Certificate revocation
list (CRL)
What needs to be installed on end users' computers to allow them to trust applications that have
been digitally signed by the developer? - ANSWER-Sender's public key
Which type of certificate must be certified by an authority to verify it with other participants? -
ANSWER-Public Certificate
What is an attribute of the Rivest Cipher 4 (RC4) algorithm? - ANSWER-It requires a unique nonce.
Which mode generates the key stream with a nonce and incrementing value? - ANSWER-Counter (CTR)
Which mode is a stream algorithm that concatenates an incrementing value with a nonce? - ANSWER-
Counter (CTR)
Which key would an administrator use to encrypt data so only the CEO can decrypt it? - ANSWER-
CEO's public key
What is the result of a hash function? - ANSWER-Digest
What is used to efficiently encrypt large files? - ANSWER-Symmetric encryption
An administrator needs to encrypt the following word with the Atbash cipher: security What is the
correct ciphertext? - ANSWER-hvxfirgb
Which cryptographic algorithm has a 128-bit hash size? - ANSWER-Message Digest Algorithm 5 (MD5)
Which characteristic makes a hashing function suitable for use in signature schemes? - ANSWER-
Collision resistance
Which attribute of a hashing function makes a birthday attack possible? - ANSWER-Partial-message
collision
Which hash algorithm produces a 160-bit output value? - ANSWER-SHA-1
What does cipher block chaining (CBC) use with the key to encrypt subsequent blocks of plaintext? -
ANSWER-Previous generated ciphertext
Which mode produces the same ciphertext from two identical plaintext blocks? - ANSWER-Electronic
codebook (ECB)
, Which encryption mode is least secure? - ANSWER-Electronic codebook (ECB)
What is the mathematical formula used for symmetric decryption? - ANSWER-P = E (K,C)
Which algorithm relies on factoring the product of large prime numbers? - ANSWER-Rivest-Shamir-
Adleman
Which encryption technology is a serial combination of hashing, data compression, symmetric-key
cryptography, and public key infrastructure (PKI) and can be used for encrypting texts, emails, files,
and directories or for full disk encryption? - ANSWER-Pretty Good Privacy (PGP)
Which concept stipulates that algorithms should be openly shared and scrutinized, but keys must be
absolutely secured? - ANSWER-Kerckhoffs's principle
Which encryption process minimizes known plaintext attacks against Advanced Encryption Standard
(AES)? - ANSWER-Randomizing the initialization vector
What prevents a rainbow table attack during the encryption process? - ANSWER-Salting
Which factor increases the required number of attempts in a brute-force attack? - ANSWER-Larger
key size
What is a vulnerability of the Data Encryption Standard (DES)? - ANSWER-Key length is too short.
Which block size does the Advanced Encryption Standard (AES) use? - ANSWER-128
Which block algorithm includes a provision for the decryption key kept in a key escrow? - ANSWER-
Skipjack
What is the result of A|B and B|C? - ANSWER-A|C
How is X mod N if N = PQ represented in number theory? - ANSWER-( X mod P, X mod Q)
What is the outcome when using the binary AND function on 11011 and 10100? - ANSWER-10000
Which mode does the Fortuna algorithm use to generate random numbers? - ANSWER-Counter (CTR)
What is a potential weakness of a pseudo-random number generator (PRNG)? - ANSWER-Same state
used more than once
Which key combination is used to decrypt and verify a digital signature? - ANSWER-Recipient's private
key to decrypt and sender's public key to verify the signature
Which key is used to sign a message or a message digest? - ANSWER-Sender's private key
Which key does the certificate authority (CA) use to digitally sign keys that it issues? - ANSWER-
Server's private key
What does an end user need to verify a Rivest-Shamir -Adleman (RSA) digitally signed message? -
ANSWER-Sender's public key
What is used when creating a digital signature, using public key infrastructure (PKI)? - ANSWER-The
private key of the person creating the message
Which feature in Wired Equivalent Privacy (WEP) provides integrity control when sending packets
over a wireless network? - ANSWER-Cyclic redundancy check
