WGU C839 OBJECTIVE ASSESSMENT /WGU C839 INTRODUCTION TO CRYPTOGRAPHY OA ACTUAL EXAM 300 QUESTIONS AND CORRECT DETAILED ANSWERS WITH RTIONALES|ALREADY GRADED A+

WGU C839 OBJECTIVE ASSESSMENT 2023-2024 /WGU C839
INTRODUCTION TO CRYPTOGRAPHY OA ACTUAL EXAM 300
QUESTIONS AND CORRECT DETAILED ANSWERS WITH
RTIONALES|ALREADY GRADED A+
____ was designed to provide built in cryptography for the clipper chip.

A Blowfish

B Skipjack

C GOST

D 3DES - ANSWER-B



Which of the following uses an 80 bit key on 64 bit blocks?

A Twofish

B AES

C Skipjack

D DES - ANSWER-C



With _____, the message is divided into blocks and each block is encrypted separately. This is the most
basic mode for symmetric encryption.

A Electronic codebook (ECB)

B Cipher-block chaining (CBC)

C Cipher feedback (CFB)

D Output feedback (OFB) - ANSWER-A



Which of the following is an example of an unbalanced Feistel?

A 3DES

B Skipjack

C Twofish

D AES - ANSWER-B

,This process is done by having each block of plaintext is XORed with the previous ciphertext block before
being encrypted.

A Output feedback (OFB)

B Cipher-block chaining (CBC)

C Electronic codebook (ECB)

D Cipher feedback (CFB) - ANSWER-B



The process wherein the ciphertext block is encrypted then the ciphertext produced is XOR'd back with
the plaintext to produce the current ciphertext block is called what?

A Output feedback (OFB)

B Cipher-block chaining (CBC)

C Cipher feedback (CFB)

D Electronic codebook (ECB) - ANSWER-C



This is a method for turning a block cipher into a stream cipher by generating a keystream block, which
are then XORed with the plaintext blocks to get the ciphertext.

A Cipher feedback (CFB)

B Electronic codebook (ECB)

C Output feedback (OFB)

D Cipher-block chaining (CBC) - ANSWER-C



Which of the following modes can be used to turn a block cipher into a stream cipher?

A Propagating cipher-block chaining (PCBC) and Electronic codebook (ECB)

B Counter Mode (CTR) and Propagating cipher-block chaining (PCBC)

C Electronic codebook (ECB) and Output feedback (OFB)

D Output feedback (OFB) and Counter Mode (CTR) - ANSWER-D



A fixed-size pseudorandom number that is fed into a symmetric cipher to increase randomness is called
what?

,A IV

B Key

C Chain

D Salt - ANSWER-A



A number that is used only one time then discarded is called what?

A Nonce

B Chain

C Salt

D IV - ANSWER-A



Which of the following is a stream cipher that uses variable length key from 1 to 256 bytes?

A RC4

B AES

C DESx

D DES - ANSWER-A



This algorithm was published by the German engineering firm Seimans in 1993. It is a software based
stream cipher using Lagged Fibonacci generator along with a concept borrowed from the shrinking
generator ciphers.

A RC4

B Blowfish

C FISH

D Twofish - ANSWER-C



Which of the following is NOT required for a hash?

A Minimum key length of 256 bits

B Variable-length input, fixed-length output

C Non-reversible

, D Few collisions - ANSWER-A



A ______ refers to a situation where two different inputs yield the same output.

A Substitution

B Convergence

C Collision

D Transposition - ANSWER-C



What is a salt?

A Key rotation

B Random bits intermixed with a hash to increase randomness and reduce collisions.

C Random bits intermixed with a symmetric cipher to increase randomness and make it more secure.

D Key whitening - ANSWER-B



RFC 1321 describes what hash?

A RIPEMD

B SHA1

C GOST

D MD5 - ANSWER-D



What size block does FORK256 use?

A 256

B 128

C 512

D 64 - ANSWER-C



In 1977 researchers at MIT described what asymmetric algorithm?

A RSA

B AES