In an RSA encryption system given that p11 and q13 The pair

In an RSA encryption system, given that p=11 and q=13. The pair of keys (public [d], private [e]) needs to be generated from p and q. The choice of one of the two keys is with some freedom, and the choice of the other key is fixed after the first key is chosen. The pair of keys can be used to encrypt and decrypt messages.

1. After you have picked d, what is the corresponding value of key e?

Solution

n = 11 *13 = 143

phi n = (11-1)*(13-1) =120

d = (1+120k)/e

for k =1

d = (1+120)/e

for d =11

we must choose

e=11