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NTC PS03EMTH55 (06-12-2024)
Question 1. If ordp(2024) = ordq(2024), then the primes p and q cannot be     .
i)
7 and 13
ii)
11 and 23
iii)
2 and 23
iv)
none of these

Question 2. The inverse of 7 in 𝔽11 is     .
i)
3
ii)
4
iii)
5
iv)
8

Question 3. For a Diffie-Hellman key-exchange, let g = 2 and p = 11. If Alice sends 3 to Bob and Bob sends 9 to Alice, then what is their shared key?
i)
9
ii)
8
iii)
6
iv)
3

Question 4. The discrete logarithm problem for the additive group of integers modulo p is solvable in     time.
i)
polynomial
ii)
sub-exponential
iii)
exponential
iv)
none of these

Question 5. 2k 4(mod77) for k =     .
i)
30
ii)
32
iii)
34
iv)
36

Question 6. Carmichael numbers need not be     .
i)
composite
ii)
odd
iii)
product of distinct primes
iv)
none of these

Question 7. Let P = (11,8) be a point on the elliptic curve E : Y 2 = X3 + 2X + 3 over 𝔽17. Then the inverse of P is     in E(𝔽17).
i)
(11,2)
ii)
(6,9)
iii)
(14,2)
iv)
(11,9)

Question 8. Which of the following is an elliptic curve?
i)
y2 = x3 12x + 16
ii)
y2 = x3 3x + 2
iii)
y2 = x3 3x 2
iv)
y2 = x3 2x + 3