Revision Flash Cards

Question 1

A __________ is any action that compromises the security of information owned by an organization.

Answer 1

security attack

Question 2

An original intelligible message fed into the algorithm as input is known as _________ , while the coded message produced as output is called the __________.

Answer 2

plaintext, ciphertext

Question 3

The methods of __________ conceal the existence of the message in a graphic image.

Answer 3

steganography

Question 4

__________ involves the passive capture of a data unit and its subsequent retransmission to produce an unauthorized effect.

Answer 4

replay

Question 5

If both sender and receiver use the same key, the system is referred to as ___________ encryption.

Answer 5

conventional

Question 6

A __________ attack involves trying every possible key until an intelligible translation of the ciphertext is obtained.

Answer 6

brute-force

Question 7

A way to improve on the simple monoalphabetic technique is to use different monoalphabetic substitutions as one proceeds through the plaintext message. The general name for this approach is ___________ .

Answer 7

polyalphabetic substitution cipher

Question 8

__________ techniques map plaintext elements (characters, bits) into ciphertext elements.

Answer 8

Substitution

Question 9

_________ refers to the use of multiple, overlapping protection approaches addressing the people, technology, and operational aspects of information systems.

Answer 9

Layering

Question 10

A common technique for masking contents of messages or other information traffic so that opponents can not extract the information from the message is ___________

Answer 10

encryption

Question 11

Triple-DES with two keys encryption uses the formula:

Answer 11

C = E(K1, D(K2, E(K1, P)))

Question 12

The output of the encryption function is fed back to the shift register in the ________ mode.

Answer 12

OFB

Question 13

__________ seeks to make the relationship between the statistics of the ciphertext and the value of the encryption key as complex as possible so that even if the attacker can get some handle on the statistics of the ciphertext, the way in which the key was used to produce that ciphertext is so complex it is difficult to deduce the key.

Answer 13

Confusion

Question 14

In the general structure of AES, the input to the encryption and decryption algorithms is a single _________ block.

Answer 14

128-bit

Question 15

The __________ is when a small change in plaintext or key produces a large change in the ciphertext

Answer 15

avalanche effect

Question 16

CFB does not conform to the typical construction of a stream cipher because:

Answer 16

the bit stream it generates depends on the plaintext

Question 17

The encryption round in AES has the structure:

Answer 17

SubBytes, ShiftRows, MixColumns, AddRoundKey

Question 18

A __________ cipher is one that encrypts a digital data one bit or one byte at a time.

Answer 18

stream

Question 19

Allowing for the maximum number of possible encryption mappings from the plaintext block is referred to by Feistel as the __________ .

Answer 19

ideal block cipher

Question 20

The _________ and _________ block cipher modes of operation are used for authentication.

Answer 20

CBC, CFB

Question 21

Asymmetric encryption can be used for __________ .

Answer 21

both confidentiality and authentication

Question 22

The Secure Hash Algorithm (SHA) is based on _____.

Answer 22

MD4 hash function

Question 23

Due to the birthday paradox, for an m-bit hash value and randomly picked data blocks, we can expect to
find two data blocks with the same hash value within ________ attempts.

Answer 23

2m/2

Question 24

Using RSA algorithm, if p = 11, q = 19, e = 13, and M = 5, then C = ______.

Answer 24

169

Question 25

The communication between A and B in the form A→B: E(K, [M||E(PRa,H(M))]) provides ____________.

Answer 25

both confidentiality and digital signature

Question 26

If two users, A and B, use Diffie-Hellman key exchange, which of the following values is NOT shared between A and B?

Answer 26

Xa