This article is about how we use a matrix to encode and decode text messages and simple strings.
Coding process:

1. Take the string conversion to the appropriate number shown below
   
   

   

2. convert to 2D matrix (array). We now have a 2 × 2 matrix!
3. When we multiply this matrix by the encoding matrix we get a 2 × 2 encoded matrix.
4. now convert to vector (1D array) and display for user

Decoding process

Take encoded number converted to 2D matrix (array)

Inverse encoding matrix !

Re-encoded matrix with inverse encoding matrix.

Convert to 1D matrix (array). then convert to the corresponding alphabets.

Code: Encode.py

# loading libraries import numpy as np   a  =   [ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ] c  =   [[ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ], [ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ]]   # encode matrix ecm = [[ 3 , 4 ], [ 3 , 6 ]] i = 0 l = 0   # Lists of alphabets and their meanings smallalpha = [ "" , "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" ] capitalalpha = [ "" , "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" ] alphavalues ​​ = [ 0 , 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 , 27 ]   # string to convert b = "India" listb = list (b) lenb = len (listb)   # Loop to convert Word to values ​​that # also useful for coding for i in range (lenb): for j in range ( 27 ): if (listb [i]  = = smallalpha [j]): a [i] = alphavalues ​​[j]   if (j  = = 23 ):   j = 0 break if (j  = = 23 ): for k in range ( 27 ):   if ( listb [i]  = = capitalalpha [k]): a [i] = alphavalues ​​[k] break      if (lenb % 2 = = 1 ): lenb = lenb + 1 a = a [ 0 : lenb] tb = b     # convert this array to 2 D array for further # multiply by encoding matrix   j = 0 k = 0   # b [m] [n] m always 2 n = int (lenb / 2 ) for i in range ( 0 , lenb):   if (j & lt; n): c [k] [j] = a [i] j = j + 1   else : k = k + 1   j = 0 c [k] [j] = a [i] j = j + 1     # Multi-user matrix with 2x2 matrix encoding c = np.matmul (ecm, c)     # Convert to 1D array for display i = 0 j = 0 k = 0 for i in r ange ( 2 ): for j  in range ( int (lenb / 2 )): a [k] = c [i ] [j] k = k + 1     a = a [ 0 : lenb] print ( " Encoding matrix = " , ecm) print ( "encrypted form = " , a)

Time complexity: O (n) (where n — message length)
Space complexity: O (n)

Output :

Code: Decode.py

# importing libraries import numpy as np from numpy.linalg import inv     # Initial values ​​ a = [ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ]    tdm = [[ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ],  [ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 ]]   # encoding matrix ecm = [[ 3 , 4 ], [ 3 , 6 ]]   # Lists of alphabets and their values ​​ smallalpha = [ "" , "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" ] capitalalpha = [ "" , "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" ] alphavalues ​​ = [ 0 , 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 , 27 ]     # Accept input # elements in the encrypted matrix lenb = 6 a = [ 63 , 46 , 12 , 81 , 48 , 12 ]   sobj = slice (lenb) a = a [sobj]   X Submit new EBook