Cryptography UK 4 Quiz 2

How many padding bits must be added to a message of 100 characters if 8-bit ASCII is used for encoding and the block cipher accepts blocks of 64 bits?

• 32

• 64

• 80

• 16

An expansion P-box is a P-box with n inputs and m outputs where ................

• m > n

• m < n

• m = n

Perform S - box and calculate for '05'

• 16

• 15

• 17

• 14

To hide the relationship between the ciphertext and the key is known as

• Diffusion

• Confusion

• Substitution

• Addition

DES is a ..............................

• ASymmetric key block cipher algorithm

• Symmetric key block cipher algorithm

• Semi Symmetric key block cipher algorithm

- 7 mod 5

• 2

• 3

• 7

• 5

a ≡ b (mod n) this implies

• Congruence Relationship

• Greatest Common Divisor

• Associative Relationship

• Commutative relationship

The algorithm is named after the ancient Greek mathematician ..........................., who first described it in his Elements around 300 BC for calculating GCD

• Euclid Algorithm

• Fermet Algorithm

• Naive Algorithm

• Euler’s Algorithm

Find the gcd of 42823 and 6409

• 17

• 15

• 1

• 0

Which of these is not a common algebraic structures?

• Rings

• Fields

• Groups

• Mod