WGU D488 Pre - Assessment (Latest Update 2025 / 2026) Cybersecurity Architecture and Engineering | Test Guide Questions and Answers | Grade A | 100% Correct (Verified Solutions)
Question:
Mode of Operation:
Answer:
used with symmetric block ciphers to enable them to work on large sets of data. Modes of operation affect the level of security provided by the underlying block cipher.
Question:
Cipher Block Chaining (CBC)
Answer:
Very simple mode. Should not be used, susceptible to the padding-oracle attack.
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Question:
Electronic Codebook (ECB)
Answer:
Simple mode, also should not be used and is susceptible to the padding- oracle attack.
Question:
Galois/Counter Mode (GCM)
Answer:
Provides authenticated encryption with associated data and is widely adopted due to its performance. A specialized form of counter mode whereby "Galois" modification provides the authentication feature.
Question:
Counter (CTR)
Answer:
Applies IV plus an incrementing counter value to the key to generate a keystream. Counter modes do not need to use padding. Any unused space in the last block is simply discarded.
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Question:
Output Feedback (OFB)
Answer:
Uses an initial Chaining vector (ICV) for the first round of encryption and combines the output of all previous rounds as input for all subsequent rounds.
Question:
Asymmetric encryption
Answer:
operations are performed by two different but related, public and private keys in a key pair. Each key is capable of reversing the operation of its pair. For example, if the public key is used to encrypt a message, only the paired private key can decrypt the ciphertext produced. The public key cannot be used to decrypt the ciphertext, even though it was used to encrypt it.
Question:
Elliptic-Curve Diffie Hellman (ECDH)
Answer:
The operation of ECDH is similar to standard DH but utilizes math based on elliptic curves instead of discrete logs, as is the case for DH.
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