WGU D830 YCN1 Task 1 Symmetric & Asymmetric
Encryption Labs | Latest Update 2026/2027 | 200
Practice Questions & Detailed Answers | RSA, AES256,
OpenSSL & SCP | Complete Lab Report | A+ Graded
SECTION I: SYMMETRIC ENCRYPTION FUNDAMENTALS (Questions 1–30)
1. In symmetric encryption, how many distinct keys are required for a secure communication between
two parties?
A) One shared key
B) Two keys, one for each party
C) Four keys, one for each direction
D) A key pair consisting of a public and private key
Correct Answer: A) One shared key
Rationale: Symmetric encryption uses a single secret key that both parties must possess. The same key
performs both encryption and decryption. This is the defining characteristic of symmetric cryptography
and also its primary weakness—the key must be securely distributed to both parties.
2. A student encrypts a file with AES256 and then needs to share it with a colleague. What must be
securely transmitted along with the encrypted file?
A) The RSA public key
B) The AES symmetric key
C) The initialization vector only
,D) The hash digest
Correct Answer: B) The AES symmetric key
Rationale: The colleague cannot decrypt the file without the AES key used to encrypt it. The key must be
transmitted through a secure channel—in the lab, this is accomplished using SCP—because anyone who
obtains the key can decrypt the data.
3. What is the primary performance advantage of symmetric encryption over asymmetric encryption?
A) Symmetric encryption provides nonrepudiation
B) Symmetric encryption is significantly faster and more efficient for bulk data
C) Symmetric encryption requires no key management
D) Symmetric encryption uses longer keys by default
Correct Answer: B) Symmetric encryption is significantly faster and more efficient for bulk data
Rationale: Symmetric algorithms like AES are orders of magnitude faster than asymmetric algorithms
like RSA. RSA involves modular exponentiation with large integers, making it unsuitable for encrypting
large files. This is why hybrid systems use AES for data and RSA only for key exchange.
4. What is the main challenge that symmetric encryption faces in practice?
A) It cannot encrypt binary files
B) Secure distribution of the shared key to both parties
C) It requires a different key for every block
,D) It is vulnerable to quantum computing
Correct Answer: B) Secure distribution of the shared key to both parties
Rationale: Because both parties must possess the identical secret key, transmitting that key without
interception is the core challenge of symmetric cryptography. This is the "key distribution problem,"
which asymmetric encryption and protocols like SCP help solve.
5. AES256 uses a key of what size?
A) 128 bits
B) 192 bits
C) 256 bits
D) 512 bits
Correct Answer: C) 256 bits
Rationale: AES256 uses a 256bit key. AES supports three key sizes: 128, 192, and 256 bits. The key size
determines the number of encryption rounds, not the block size, which is always 128 bits for AES.
6. How many rounds of encryption does AES256 perform?
A) 10
B) 12
C) 14
D) 16
, Correct Answer: C) 14
Rationale: AES128 performs 10 rounds, AES192 performs 12 rounds, and AES256 performs 14 rounds.
The increased round count for larger keys provides a greater security margin against cryptanalytic
attacks.
7. AES encrypts data in blocks of what size?
A) 64 bits
B) 128 bits
C) 192 bits
D) 256 bits
Correct Answer: B) 128 bits
Rationale: AES is a block cipher with a fixed 128bit block size, regardless of whether the key is 128, 192,
or 256 bits. The key size affects the number of rounds, while the block size determines how much data is
processed at once.
8. In the YCN1 lab, what command is used to generate a random AES256 key?
A) `openssl genrsa out key.pem 256`
B) `openssl rand hex 32 > keyfile`
C) `openssl aes256cbc genkey`
D) `openssl enc aes256cbc keygen`
Encryption Labs | Latest Update 2026/2027 | 200
Practice Questions & Detailed Answers | RSA, AES256,
OpenSSL & SCP | Complete Lab Report | A+ Graded
SECTION I: SYMMETRIC ENCRYPTION FUNDAMENTALS (Questions 1–30)
1. In symmetric encryption, how many distinct keys are required for a secure communication between
two parties?
A) One shared key
B) Two keys, one for each party
C) Four keys, one for each direction
D) A key pair consisting of a public and private key
Correct Answer: A) One shared key
Rationale: Symmetric encryption uses a single secret key that both parties must possess. The same key
performs both encryption and decryption. This is the defining characteristic of symmetric cryptography
and also its primary weakness—the key must be securely distributed to both parties.
2. A student encrypts a file with AES256 and then needs to share it with a colleague. What must be
securely transmitted along with the encrypted file?
A) The RSA public key
B) The AES symmetric key
C) The initialization vector only
,D) The hash digest
Correct Answer: B) The AES symmetric key
Rationale: The colleague cannot decrypt the file without the AES key used to encrypt it. The key must be
transmitted through a secure channel—in the lab, this is accomplished using SCP—because anyone who
obtains the key can decrypt the data.
3. What is the primary performance advantage of symmetric encryption over asymmetric encryption?
A) Symmetric encryption provides nonrepudiation
B) Symmetric encryption is significantly faster and more efficient for bulk data
C) Symmetric encryption requires no key management
D) Symmetric encryption uses longer keys by default
Correct Answer: B) Symmetric encryption is significantly faster and more efficient for bulk data
Rationale: Symmetric algorithms like AES are orders of magnitude faster than asymmetric algorithms
like RSA. RSA involves modular exponentiation with large integers, making it unsuitable for encrypting
large files. This is why hybrid systems use AES for data and RSA only for key exchange.
4. What is the main challenge that symmetric encryption faces in practice?
A) It cannot encrypt binary files
B) Secure distribution of the shared key to both parties
C) It requires a different key for every block
,D) It is vulnerable to quantum computing
Correct Answer: B) Secure distribution of the shared key to both parties
Rationale: Because both parties must possess the identical secret key, transmitting that key without
interception is the core challenge of symmetric cryptography. This is the "key distribution problem,"
which asymmetric encryption and protocols like SCP help solve.
5. AES256 uses a key of what size?
A) 128 bits
B) 192 bits
C) 256 bits
D) 512 bits
Correct Answer: C) 256 bits
Rationale: AES256 uses a 256bit key. AES supports three key sizes: 128, 192, and 256 bits. The key size
determines the number of encryption rounds, not the block size, which is always 128 bits for AES.
6. How many rounds of encryption does AES256 perform?
A) 10
B) 12
C) 14
D) 16
, Correct Answer: C) 14
Rationale: AES128 performs 10 rounds, AES192 performs 12 rounds, and AES256 performs 14 rounds.
The increased round count for larger keys provides a greater security margin against cryptanalytic
attacks.
7. AES encrypts data in blocks of what size?
A) 64 bits
B) 128 bits
C) 192 bits
D) 256 bits
Correct Answer: B) 128 bits
Rationale: AES is a block cipher with a fixed 128bit block size, regardless of whether the key is 128, 192,
or 256 bits. The key size affects the number of rounds, while the block size determines how much data is
processed at once.
8. In the YCN1 lab, what command is used to generate a random AES256 key?
A) `openssl genrsa out key.pem 256`
B) `openssl rand hex 32 > keyfile`
C) `openssl aes256cbc genkey`
D) `openssl enc aes256cbc keygen`
