WGU INTRODUCTION TO CRYPTOGRAPHY
C839 COMPLETE REVIEW PACK WITH
EXPLANATIONS
◉ 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.
C839 COMPLETE REVIEW PACK WITH
EXPLANATIONS
◉ 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.
