Question 1

If the key is 110100001, the output of the SP network for the plaintext: 101110001 is
A)110100011
B)110101110
C)10110111
D)11111010

Accepted Answer

B

Question 2

What is the number of possible 3 x 3 affine cipher transformations
A)168
B)840
C)1024
D)1344

Accepted Answer

The number of possible 3x3 affine cipher transformations is determined by the number of invertible 3x3 matrices over the finite field of size 26, which is calculated as 26^3 * (1 - 1/26) * (1 - 1/26^2) * (1 - 1/26^3) = 1344.

Question 3

What is the expanded key size of AES-192?
A)44 words
B)60 words
C)52 words
D)36 words

Accepted Answer

AES-192 has an expanded key size of 52 words, as it requires 52 words for the key schedule, with each word being 4 bytes.

Question 4

In affine block cipher systems if f(m)=Am + t, what is f(m1+m2+m3) ?
A)f(m1) + f(m2) + f(m3) + t
B)f(m1) + f(m2) + f(m3) +2t
C)f(m1) + f(m2) + f(m3)
D)2(f(m1) + f(m2) + f(m3))

Accepted Answer

The answer of In affine block cipher systems if f(m)=Am...

Question 5

The 4×4 byte matrices in the AES algorithm are called
A)states
B)words
C)transitions
D)permutations

Accepted Answer

In the AES (Advanced Encryption Standard) algorithm, the 4×4 byte matrices are referred to as "states." These states are used throughout the AES encryption and decryption processes.

Question 6

If the block size is 's', how many affine transformations are possible ?
A)2s (2s-1)(2s-1)(2s-12) ………(2s-1(s-1))
B)2s (2s-1)(2s-2)(2s-22) ………(2s-2(s-2))
C)2ss (2s-1)(2s-2)(2s-22) ………(2s-2(s-1))
D)2s (2s-1)(2s-2)(2s-22) ………(2s-2(s-3))

Accepted Answer

The number of affine transformations possible for a block size 's' is given by the formula 2^s * s! * (2^s - 1) * (2^s - 2) * ... * (2^s - 2^(s-1)), which matches the pattern in option C.

Question 7

For the AES-128 algorithm there are__________ similar rounds and_________round is different.
A)2 pair of 5 similar rounds ; every alternate
B)9 ; the last
C)8 ; the first and last
D)10 ; no

Accepted Answer

AES-128 consists of 10 rounds in total for encryption, where the first 9 rounds are similar, involving all four steps (SubBytes, ShiftRows, MixColumns, AddRoundKey), and the 10th (last) round is different because it omits the MixColumns step.

Question 8

The DES Algorithm Cipher System consists of _________rounds (iterations) each with a round key
A)9
B)12
C)18
D)16

Accepted Answer

The DES Algorithm Cipher System consists of 16 rounds (iterations), each with a round key.

Question 9

DES follows
A)hash algorithm
B)caesars cipher
C)feistel cipher structure
D)sp networks

Accepted Answer

DES (Data Encryption Standard) utilizes the Feistel cipher structure for its encryption process.

Question 10

Every cyclic group is_______.
A)a group with finite order
B)a group with prime order
C)a non abelian group
D)an abelian group

Accepted Answer

Cyclic groups are defined by the property that each element can be generated by repeatedly applying the group operation to a particular element (or its inverse). This inherently means that the group operation is commutative, making all cyclic groups abelian.

Question 11

In the DES algorithm the round key is_________bit and the Round Input is__________bits
A)48, 32
B)64,32
C)56, 24
D)32, 32

Accepted Answer

In the DES algorithm, the round key is 48 bits and the round input is 32 bits.

Question 12

__________is not a binary operation on the set of natural numbers.
A)addition
B)product
C)difference
D)none

Accepted Answer

A binary operation on a set is an operation that takes two elements from the set and produces another element of the same set. The difference between two natural numbers is not always a natural number (e.g., 1 - 2 = -1, which is not a natural number), making subtraction (difference) not a binary operation on the set of natural numbers.

Question 13

In the DES algorithm the Round Input is 32 bits, which is expanded to 48 bits via
A)scaling of the existing bits
B)duplication of the existing bits
C)addition of zeros
D)addition of ones

Accepted Answer

The answer of In the DES algorithm the Round Input...

Question 14

Which of the following is group under multiplication?
A)q
B)q-{0}
C)q-{1}
D)q-{0,1}

Accepted Answer

A group under multiplication requires a set to be closed under multiplication, to have an identity element, and every element must have an inverse. The set of all rational numbers excluding 0, denoted by Q-{0}, meets these criteria because the product of any two non-zero rational numbers is a non-zero rational number (closure), the identity element is 1 (since any number multiplied by 1 is itself), and every non-zero rational number has a multiplicative inverse (1/a is the inverse of a, where a is non-zero).

Question 15

The Initial Permutation table/matrix is of size
A)16×8
B)4×8
C)12×8
D)8×8

Accepted Answer

The Initial Permutation table/matrix used in the DES (Data Encryption Standard) algorithm is of size 8×8, which rearranges the 64 bits of its input block according to a fixed table.

Question 16

The number of unique substitution boxes in DES after the 48 bit XOR operation are
A)8
B)4
C)6
D)12

Accepted Answer

DES uses 8 unique substitution boxes (S-boxes) after the initial 48-bit XOR operation to perform non-linear substitution, which is crucial for the encryption process.

Question 17

The DES algorithm has a key length of
A)128 bits
B)32 bits
C)64 bits
D)16 bits

Accepted Answer

The DES (Data Encryption Standard) algorithm uses a key length of 64 bits. However, out of these 64 bits, 56 bits are used for the actual encryption key, and 8 bits are used for parity checks.

Question 18

What is the size of the key in the SDES algorithm?
A)24 bits
B)16 bits
C)20 bits
D)10 bits

Accepted Answer

The Simplified Data Encryption Standard (SDES) uses a key size of 10 bits.

Question 19

The Plaintext for the Ciphertext 10100101, given that the key is 0010010111 is
A)1100111
B)110110
C)1001000
D)1001100

Accepted Answer

The answer of The Plaintext for the Ciphertext 10100101, given...

Question 20

Assume input 10-bit key, K: 1010000010 for the SDES algorithm. What is K1?
A)10100100
B)1011011
C)1101000
D)10100111

Accepted Answer

K1 is derived from the 10-bit key K through several steps: permutation P10, a left shift operation, and finally permutation P8. The correct K1 after these operations on the given key 1010000010 is 10100100.

Quiz 3: Cryptography Key, Algorithm, and Mode of Operation

If the key is 110100001, the output of the SP network for the plaintext: 101110001 is

What is the number of possible 3 x 3 affine cipher transformations

What is the expanded key size of AES-192?

In affine block cipher systems if f(m) =Am + t, what is f(m1+m2+m3) ?

The 4×4 byte matrices in the AES algorithm are called

If the block size is 's', how many affine transformations are possible ?

For the AES-128 algorithm there are__ similar rounds and_round is different.

The DES Algorithm Cipher System consists of _________rounds (iterations) each with a round key

DES follows

Every cyclic group is_______.

In the DES algorithm the round key is_bit and the Round Input is__bits

__________is not a binary operation on the set of natural numbers.

In the DES algorithm the Round Input is 32 bits, which is expanded to 48 bits via

Which of the following is group under multiplication?

The Initial Permutation table/matrix is of size

The number of unique substitution boxes in DES after the 48 bit XOR operation are

The DES algorithm has a key length of

What is the size of the key in the SDES algorithm?

The Plaintext for the Ciphertext 10100101, given that the key is 0010010111 is

Assume input 10-bit key, K: 1010000010 for the SDES algorithm. What is K1?