Question

5. Encipher the message WASHINGTON using the Hill cipher with key ma- trix A = 19 8

Answer 1

Given matrix A = [3 9 7 8] Message: WASHINGTON Since each Letter A, B, C, D, E assign number as per their position 0, 1, 2, 3 so on. A rightarrow 0, B rightarrow 1, C rightarrow 2 Z rightarrow 25 Since matrix is 2 times 2 so we break letters in pairs [W A] = [22 0], [S H] = [18 7], [I N] = [8 13] [G T] = [6 19], [O N] = [14 13] Now multiply each matrix with A [3 9 7 8] [22 0] = [14 16] (mod 26) rightarrow [O Q] [3 9 7 8] [18 7] = [25 16] (mod 26) rightarrow [Z Q] [3 9 7 8] [8 13] = [11 20] (mod 26) rightarrow [L U] [3 9 7 8] [6 17] = [21 24] (mod 26) rightarrow [V T] \r\n [3 9 7 8] [14 13] = [3 22] (mod 26) rightarrow [D W] So arranging Letter