Question

Discrete

4. Consider the cryptosystem in which the integer I associated with a letter is transformed into f(x) = 4.c mod 26. (a) Find the function f-1(2) that will decrpt. (b) Into which secret word is the word DISCRETE transformed? (c) Which word is transformed into the secret word FOYN?

Answer 1

4. Consider the cryptosystem in which the integer I associated with a letter is transformed into f(x) = 4.c mod 26

&& Given function f(n) = 4x amod 26 find a ů mod 26 By using Euclideans algorithm we can calculate f (x) 4 = 27 (2) +} 2-2017 to If we want to find the fin) we need to get value as I otherwise we can't find thei fin for the to)= un mod 26) for this problein we got o so it is not possible to find fix) b) DISCRETE To find this we need to take all at Z values ietvany orto Z=25 D: 4x. 3 mod 26=) 12=M. la ux8 modze=32 mod 26 =) 6 =) . sauxiq mod 26 = 72 mod 26 = 20 =) caux2 mod 26 28 mod 26=) 8 ) I

R = 4x17 mod 26 = 68 mod 26 = 16 = 9 E = 4x4 mod 26 = 16 mod 26 = 16 = 9 Ta ux19 mod 26 = 76 mod 26 =) 24 = 4 Eaux u mod 26 = 16 mod 26 = 1629 DISCRETE = MGUIQQ yg 7th FOUN F = ux5 mod 26 =20 mod 26 - 2020 0 =) uxlle mod. 26 = 56 mod 26 aut y =) u x 24 mod26 = 96 mod 26 =) 18 as N=) ux13 mod 26.= 52 mod 26 =) o=A . FOYN = VESA .