Let f(a;b) & f(c;d) be two affine ciphers s/t

Question

f(a;b)(x) � (a:x + b) mod 26
f(c;d)(x) � (c:x + d) mod 26
Is f(c;d) � f(a;b) a stronger encryption scheme than f(a;b)?
(10)
Using Affine Cipher Theory and given;a=9 and b=4, Encrpt the word "MAZERAS" and show the resulting cipher text.

Answer 1

To encrypt the word "MAZERAS" using the affine cipher, we need to apply the encryption function f(a;b)(x) = (ax + b) mod 26.

Given a = 9 and b = 4, we can substitute these values into the encryption function.

For the letter 'M':
Using the numerical representation of the alphabet (A = 0, B = 1, ..., Z = 25), 'M' is represented by the number 12.
The cipher equation becomes: f(9;4)(12) = (9*12 + 4) mod 26 = 109 mod 26 = 3.
So, the encrypted letter for 'M' is 'C'.

Similarly, we can encrypt the remaining letters:
'A' -> f(9;4)(0) = (9*0 + 4) mod 26 = 4 mod 26 = 4 -> 'E'
'Z' -> f(9;4)(25) = (9*25 + 4) mod 26 = 229 mod 26 = 21 -> 'V'
'E' -> f(9;4)(4) = (9*4 + 4) mod 26 = 40 mod 26 = 14 -> 'O'
'R' -> f(9;4)(17) = (9*17 + 4) mod 26 = 157 mod 26 = 5 -> 'F'
'A' -> f(9;4)(0) = (9*0 + 4) mod 26 = 4 mod 26 = 4 -> 'E'
'S' -> f(9;4)(18) = (9*18 + 4) mod 26 = 166 mod 26 = 14 -> 'O'

So, the resulting ciphertext for the word "MAZERAS" is "CEVOFE".

To answer the second part of your question, whether f(c;d) is a stronger encryption scheme than f(a;b), we would need the values of c and d for a proper comparison. Without these values, it is not possible to determine the strength of one encryption scheme over the other.