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NTC PS03EMTH55 (11-11-2022)
Question 1. The division step in Euclidean algorithm is executed at most     times.
i)
log 2(b) + 1
ii)
2log 2(b)
iii)
log 2(b) + 2
iv)
2log 2(b) + 1

Question 2. Let p be a prime such that ap1 1(modp). Then     must be necessarily true.
i)
gcd (a,p)1
ii)
a is primitive root
iii)
order of a is p 1
iv)
none of these

Question 3. The discrete logarithm problem for the group 𝔽p is solvable in     time.
i)
linear
ii)
exponential
iii)
quadratic
iv)
sub-exponential

Question 4. The function     O(    ).
i)
xcos 2(x), cos 2(x)
ii)
(x + 2)cos 2(x), 2x
iii)
(x + 2)cos 2(x), x2
iv)
xcos 2(x), x + 2

Question 5. In RSA, the smallest possible value of the encryption exponent, for which ciphertext is different plaintext, is     .
i)
1
ii)
2
iii)
3
iv)
none of these

Question 6.     is a witness for the compositeness of 6.
i)
4
ii)
3
iii)
2
iv)
1

Question 7. The curve Y 2 =     is not an elliptic curve.
i)
X3 X
ii)
X3 3X + 3
iii)
X3 + 3X + 8
iv)
X3 + X2

Question 8. Let tp denote the trace of Frobenius for an elliptic curve over 𝔽p. Then |tp|     .
i)
2p
ii)
p
iii)
2p
iv)
2p