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Anonymous
Anonymous asked in Science & MathematicsMathematics · 8 months ago

Ciphers and Modular?

How to answer a and b, I have no idea how to do this question. Please help!!!

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  • Alan
    Lv 7
    8 months ago
    Favorite Answer

    So this gives the following encoding

    0 3

    1 12

    2 21

    3 4

    4 13

    5 22

    6 5

    7 14

    8 23

    9 6

    10 15

    11 24

    12 7

    13 16

    14 25

    15 8

    16 17

    17 0

    18 9

    19 18

    20 1

    21 10

    22 19

    23 2

    24 11

    25 20

    26 3

    C = (9p+3) -26k where k is based how big (9p+3)

    D(C) = (aC + b) -26k

    so you know (0,17) is point pair

    17 = b-26k

    so 1st let's hope this is for k = 0

    then , check next point (1,20)

    P = aC + 17-26k

    20 = a + 17-26k

    3 = a-26k

    so if we are lucky again this is k = 0

    so try

    D(c) = 3c + 17 (mod 26 )

    try it for all values and see that it works

    That is, it maps all encoded values back to their original values.

    otherwise, we would have to check so

    of the other possible k values.

    D = 3c +17 (mod 26)

    so a = 3 and b =17

    now for next part

    GZQ is 6 , 25, 16

    1st Char = 3*6 + 17 mod 26

    1st Char = 35 mod 26

    1st char = 9 a "J"

    2nd char = 3*25 +17 mod 26

    2nd char = 14 an "O"

    3rd char = 16*3 +17 mod 26

    3rd char = 13 at "N"

    answer "JON"

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