Making and decoding a code message

Making a coded message

• Decide on a message• Decide on a key word• Form a matrix using the key word repeated over

and over. Number of row sufficient to cover the number of letters in the message.

• Make a matrix using the message. Fill the end in with 0s.

• Add the matrixes' together and rewrite the message.

Alphabet numbering

1 2 3 4 5 6 7 8 9 10 11 12 13

14 15 16 17 18 19 20 21 22 23 24 25 26

A B C D E F G H I J K L M

N O P Q R S T U V W X Y Z

Example1• Message – Making codes is fun and easy to do.

(13,1,11,9,14,7,0,3,15,4,5,19,0,9,19,0,6,21,14,0,1,14,4,5,1,19,25,0,20,15,0,4,15)

• Key word – cough (3,15,21,7,8)

3 15 21 7 8

3 15 21 7 8

3 15 21 7 8

3 15 21 7 8

3 15 21 7 8

3 15 21 7 8

3 15 21 7 8

13 1 11 9 14

7 0 3 15 4

5 19 0 9 19

0 6 21 14 0

1 14 4 0 5

1 19 25 0 20

15 0 4 15 0

Add the two matrixes and rewrite the message

3 15 21 7 8 13 1 11 9 14 16 16 32 16 22

3 15 21 7 8 7 0 3 15 4 10 15 24 22 12

3 15 21 7 8 5 19 0 9 19 8 34 21 16 27

3 15 21 7 8 0 6 21 14 0 3 21 42 21 8

3 15 21 7 8 1 14 4 0 5 4 29 25 7 13

3 15 21 7 8 1 19 25 0 20 4 34 46 7 28

3 15 21 7 8 15 0 4 15 0 18 1

5 25 22 8

The message sent is

• 16, 16, 32, 16, 22, 10, 15, 24, 22, 12, 8, 34, 21, 16, 27, 3, 21, 42, 21, 8, 4, 29, 25, 7, 13, 4, 34, 46, 7, 28, 18, 15, 25, 22, 8

» From Cough

Decoding the message

• Start by finding the dimensions of the two matrixes.

• Subtract the two matrixes.• Substitute the letters for your new numbers.

• Since cough is five letters then both matrixes are going to be something by five16, 16, 32, 16, 22, 10, 15, 24, 22, 12, 8, 34, 21, 16, 27, 3, 21, 42, 21, 8, 4, 29, 25, 7, 13, 4, 34, 46, 7, 28, 18, 15, 25, 22, 8Cough 3, 15, 21, 7, 816 16 32 16 22

10 15 24 22 12

8 34 21 16 27

3 21 42 21 8

4 29 25 7 13

4 34 46 7 28

18 15 25 22 8

3 15 21 7 8

3 15 21 7 8

3 15 21 7 8

3 15 21 7 8

3 15 21 7 8

3 15 21 7 8

3 15 21 7 8

Subtract the two matrixes16 16 32 16 22 3 15 21 7 8 13 1 11 9 14

10 15 24 22 12 3 15 21 7 8 7 0 3 15 4

8 34 21 16 27 3 15 21 7 8 5 19 0 9 19

3 21 42 21 8 3 15 21 7 8 0 6 21 14 0

4 29 25 7 13 3 15 21 7 8 1 14 4 0 5

4 34 46 7 28 3 15 21 7 8 1 19 25 0 20

18 15 25 22 8 3 15 21 7 8 1

5 0 4 15 0

• 13,1,11,9,14,7,0,3,15,4,5,19,0,9,19,0,6,21,14,0,1,14,4,5,1,19,25,0,20,15,0,4,15

• Making codes is fun and easy to do

45, 38, 26, 14, 39, 33, 35, 44, 17, 18, 20, 27, 25, 23, 21, 32, 35, 46, 24, 23, 25, 22, 21, 45, 20, 48, 20, 35, 20, 28, 21, 37, 5, 33, 35, 37, 42, 28, 5, 34, 28, 34, 39, 23, 8, 29, 24, 30

From Twenty

1 2 3 4 5 6 7 8 9 10 11 12 13

14 15 16 17 18 19 20 21 22 23 24 25 26

A B C D E F G H I J K L M

N O P Q R S T U V W X Y Z