1. In GCM, we define S as S = GHASH(A||0^v||C||0^u||[len(A)]||[len(C)]). What is v defined as?

a) 64 ceil[len (A)/128] – len (A)

b) 64 ceil[len (C)/128] – len (C)

c) 128 ceil[len (A)/128] – len (A)

d) 128 ceil[len (C)/128] – len (C)

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2. When the length of the IV is not 96, then

a) we append the rest of the bits with 1*0 to make it 128 bits

b) we append the rest of the bits with 0*1 to make it 128 bits

c) we append the rest of the bits with 1*0 to make it 256 bits

d) we append the rest of the bits with 0s to make it 128 bits

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3. Which is not true for Key-Wrapping?

a) Used for small Plain Texts

b) It has a relatively higher throughput than other modes

c) It has block size of 64 bits

d) It has n+1 cipher blocks, for n plaintext block

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4. What is the value of A (0)?

a) F9*

b) A9*

c) A6*

d) F6*

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5. The cipher block is one block longer than the plaintext to accommodate the IV.

a) True

b) False

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6. The key Wrapping Algorithm provides confidentiality and data integrity.

a) True

b) False

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7. Which of the following is a valid disadvantage of the PRNG based on MAC function?

a) It has a high throughput

b) It takes twice the execution time

c) It is hardware intensive and can only work on high end processors

d) none of the mentioned

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8.

i)

m = [ n/outlen]

w_o = V

W = the null string

For i = 1 to m

w_i = MAC(K,w_i-1)

W = W || wi

Return leftmost n bits of W

ii)

m = [n/outlen]

W = the null string

For i = 1 to m

w_i = MAC(K,V || i)

W = W || w_i

Return leftmost n bits of W

iii)

m = [n/outlen]

A(0) = V

W = the null string

For I = 1 to m

A(i) = MAC (K,A(i-1))

w_i = MAC (K, a(I) || v)

W = W || w_i

Return leftmost n bits of W

Specify in the correct order (from top to bottom), which Pseudo Random Number Generation schemes are represented here?

a) NIST SP 800-90 ; TLS/WTLS ; IEEE 802.11

b) TLS/WTLS ; NIST SP 800-90 ; IEEE 802.11

c) IEEE 802.11 ; NIST SP 800-90 ; TLS/WTLS

d) NIST SP 800-90 ; IEEE 802.11 ; TLS/WTLS