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NTC PS03EMTH55 (12-04-2024)
Question 1. The number of primitive roots in 𝔽23 is     .
i)
10
ii)
11
iii)
22
iv)
none of these

Question 2. The inverse of 7 modulo 11 is     .
i)
3
ii)
4
iii)
5
iv)
8

Question 3. If there is a constant c > 0 such that for inputs of size O(k) bits, there is an algorithm to solve a problem in O(eck) steps, then the problem is said to be solvable in     time.
i)
linear
ii)
quadratic
iii)
sub-exponential
iv)
exponential

Question 4. Which of the following is not explicitly based on the difficulty of the discrete logarithm problem?
i)
Diffie-Hellman key exchange
ii)
Elgamal public key cryptosystem
iii)
RSA public key cryptosystem
iv)
none of these

Question 5. Carmichael numbers are     .
i)
even
ii)
primes
iii)
composite
iv)
finitely many

Question 6. Let π(X) = (# of primes p satisfying 2 p X). Then π(X)ϕ(X) if X =    .
i)
4
ii)
8
iii)
10
iv)
none of these

Question 7. Which of the following elliptic curves has no non-trivial points over 𝔽3?
i)
Y 2 = X3 + X
ii)
Y 2 = X3 X
iii)
Y 2 = X3 X + 1
iv)
Y 2 = X3 + 2X + 2

Question 8. The fastest known algorithm to solve ECDLP in E(𝔽p) takes approximately     steps.
i)
log p
ii)
p
iii)
log p
iv)
log p