Question

If P = (1,4) in the elliptic curve E13(1, 1) , then 4P is

(a) (4, 2)

(b) (7, 0)

(c) (5, 1)

(d) (8, 1)

This question was posed to me in examination.

Origin of the question is Elliptic Curve Arithmetic/Cryptography topic in division Other Public Key Cryptosystems and Cryptographic Hash Functions of Cryptograph & Network Security

Answer 1

Correct choice is (d) (8, 1)

The best explanation: Apply ECC via adding P+P=2P       then, 4P=2P+2P.