Question

In RSA, Ф(n) = _______ in terms of p and q.

(a) (p)/(q)

(b) (p)(q)

(c) (p-1)(q-1)

(d) (p+1)(q+1)

I have been asked this question during an interview.

Origin of the question is Knapsack/ Merkle in section Public Key Cryptography and RSA of Cryptograph & Network Security

Answer 1

The correct option is (c) (p-1)(q-1)

Easiest explanation: Ф(n) = (p-1)(q-1).