Introduction-to-Cryptography試験の準備方法|素敵なIntroduction-to-Cryptography復習攻略問題試験|効果的なWGU Introduction to Cryptography HNO1トレーニング科学技術の発展は、私たちの生活をより快適で便利なものにし、より多くの課題をもたらしています。多くの企業は、候補者に実務経験だけでなく、いくつかの専門的な資格も要求しています。したがって、より良い未来への道を開くには、専門のWGU認定を取得する必要があります。当社が作成したIntroduction-to-Cryptographyの質問と回答は、お客様がIntroduction-to-Cryptography試験に合格し、数日以内にIntroduction-to-Cryptography認定を取得するのに役立ちます。 Introduction-to-Cryptography試験問題が最適です。 WGU Introduction to Cryptography HNO1 認定 Introduction-to-Cryptography 試験問題 (Q10-Q15):質問 # 10
(Which mechanism implemented in WPA-Enterprise guards against bit-flipping exploits?)
A. Pre-shared key (PSK)
B. Advanced Encryption Standard (AES)
C. Message Integrity Check (MIC)
D. Global encryption key
正解:C
解説:
Bit-flipping exploits target encryption modes or protocols that do not provide strong integrity, allowing attackers to modify ciphertext so that predictable changes occur in plaintext after decryption. To defend against this, protocols add an integrity mechanism that detects tampering. In WPA (including enterprise deployments), TKIP introduced a Message Integrity Check (MIC) called "Michael." The MIC is computed over the frame contents (with additional fields) and verified by the receiver; if an attacker flips bits in transit, the MIC verification fails, and the frame is rejected. While AES (used by WPA2's CCMP) also provides integrity via authenticated encryption, the option presented that directly names the tamper-detection mechanism associated with guarding against bit-flipping is MIC. A pre- shared key is an authentication/keying method (and not enterprise-mode anyway), and a "global encryption key" would be the opposite of what you want-global/static keys worsen security.
Therefore, the intended mechanism that mitigates bit-flipping by detecting unauthorized modifications is the Message Integrity Check.
質問 # 11
(What is the length of the Initialization Vector (IV) in WEP?)
A. 48 bits
B. 56 bits
C. 24 bits
D. 40 bits
正解:C
解説:
WEP (Wired Equivalent Privacy) uses the RC4 stream cipher and combines a per-packet Initialization Vector (IV) with a shared secret key to form the RC4 seed for that packet's keystream. The IV in WEP is 24 bits long and is transmitted in the clear as part of the 802.11 frame so the receiver can reconstruct the same per-packet RC4 key stream. The short IV space (2²# possible values) is a major design weakness: on a busy network, IVs repeat frequently, causing keystream reuse. Because RC4 is a stream cipher, keystream reuse enables attackers to derive relationships between plaintexts and recover keys with statistical attacks (notably the Fluhrer, Mantin, and Shamir (FMS) family of attacks and related improvements). WEP also uses a CRC-32 integrity check (ICV) that is not cryptographically strong and is vulnerable to modification attacks. The 24-bit IV length is therefore a key reason WEP is considered insecure and has been replaced by WPA/WPA2 mechanisms that use stronger key mixing, larger nonces/IVs, and robust integrity protection.
質問 # 12
(A security analyst is using 3DES for data encryption. Which 3DES key size is valid?)
A. 112-bit
B. 56-bit
C. 128-bit
D. 2,048-bit
正解:A
解説:
3DES (Triple DES) applies the DES block cipher three times to increase effective security, and its commonly cited valid key sizes correspond to how many independent DES keys are used. Two-key
3DES uses two 56-bit DES keys (K1 and K2) in an EDE sequence (Encrypt with K1, Decrypt with K2, Encrypt with K1), yielding 112 bits of keying material (ignoring parity bits). Three-key 3DES uses three independent 56-bit keys for a total of 168 bits of keying material, but that option is not listed here.
A 56-bit key corresponds to single DES, not 3DES. 128-bit is associated with AES, not 3DES. 2,048-bit is typical for RSA keys, not symmetric ciphers. Therefore, among the choices provided, 112-bit is a valid 3DES key size. While 3DES is now deprecated for many uses due to its 64-bit block size and performance limitations, understanding its keying options remains important for legacy system assessment.
質問 # 13
(What is the correlation between the number of rounds and the key length used in the AES algorithm?)
A. The number of rounds is the same regardless of the key length.
B. The number of rounds increases as the key length increases.
C. The number of rounds decreases as the key length increases.
D. The key length is the same regardless of the number of rounds.
正解:B
解説:
In AES, the number of rounds is explicitly tied to the key length. AES-128 uses 10 rounds, AES-192 uses 12 rounds, and AES-256 uses 14 rounds. The purpose of additional rounds is to increase diffusion and confusion, strengthening resistance against cryptanalysis as the key schedule and state transformations iterate more times. Although key length primarily affects brute-force resistance, AES's designers and standardization parameters link longer keys with more rounds to maintain security margins across variants, especially considering differences in the key schedule structure. Thus, as key length increases from 128 to 192 to 256 bits, the number of rounds increases correspondingly from 10 to
12 to 14. This relationship is fixed by the AES specification and does not vary dynamically at runtime.
Therefore, the correct correlation is that the number of rounds increases as the key length increases.
質問 # 14
(What is the value of 23 mod 6?)
A. 04
B. 06
C. 03
D. 05
正解:D
解説:
The expression 23 mod 6 asks for the remainder when 23 is divided by 6. Modular arithmetic is foundational in cryptography, especially in public-key systems (RSA, Diffie-Hellman, ECC) where operations occur in finite rings or fields. To compute 23 mod 6, identify the largest multiple of 6 that does not exceed 23. Multiples of 6 are 6, 12, 18, 24. Since 24 is greater than 23, the largest valid multiple is 18. Subtract: 23 # 18 = 5, so the remainder is 5. Therefore, 23 mod 6 = 5, which corresponds to option
"05." Modular reduction keeps numbers within a fixed range (0 to modulus#1), enabling stable arithmetic under wraparound behavior. In cryptographic protocols, this wraparound property is essential for defining groups and ensuring operations remain bounded and consistent.