Question

In a Caesar Cipher system, if encryption is done by the rule c = E(p+k) = p + 9, then the letter ‘q’ is encrypted as what other letter?

Answer 1

Answer:

i

Step-by-step explanation:

There has to be a mod 26 operation for c, since the alphabet only has 26 letters.

But otherwise

$c = E(p+k) = p + 9 \mod{26}$

p is the initial position of the letter. So for example, a = 0, b = 1, c = 2, q = 16, z = 25...

9 is by how much the encrypted character will change relative to the original.

We want to cipher the letter q.

So p = 25.

$c = E(p+k) = p + 9 \mod{26}$

$c = 25 + 9 \mod{26}$

$c = 34 \mod{26}$

The remainder of 34 divided by 26 is 8.

So

$c = 8$

Which means that q is encrypted as 'i'.