1. DES follows

a) Hash Algorithm

b) Caesars Cipher

c) Feistel Cipher Structure

d) SP Networks

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2. The DES Algorithm Cipher System consists of ____________rounds (iterations) each with a round key

a) 12

b) 18

c) 9

d) 16

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3. The DES algorithm has a key length of

a) 128 Bits

b) 32 Bits

c) 64 Bits

d) 16 Bits

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4. In the DES algorithm, although the key size is 64 bits only 48bits are used for the encryption procedure, the rest are parity bits.

a) True

b) False

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5. 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

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6. 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

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7. The Initial Permutation table/matrix is of size

a) 16×8

b) 12×8

c) 8×8

d) 4×8

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

a) 8

b) 4

c) 6

d) 12

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9. In the DES algorithm the 64 bit key input is shortened to 56 bits by ignoring every 4th bit.

a) True

b) False