In RSA p and q are chosen as very large prime numbers Compute n = p q and ϕ(n)…
2020
In RSA
p and q are chosen as very large prime numbers
Compute n = p q and ϕ(n) = (p−1) (q−1)
Later e encryption key is chosen. How is this encryption key selected?
- A.
e is chosen as a relative prime to q
- B.
e is chosen as a relative prime to p
- C.
e is chosen as a relative prime to ϕ(n)
- D.
e is chosen as a relative prime to n
Attempted by 139 students.
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Correct answer: C
The encryption key e is selected such that 1 < e < φ(n) and gcd(e, φ(n)) = 1. This ensures e is coprime to φ(n), allowing a valid decryption key d to exist.