Introduction-to-Cryptography Exam Dumps : WGU Introduction to Cryptography HNO1

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.

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.

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.