Python program.py

# -*- coding: utf-8 -*-
"""Encryption & Decryption

Automatically generated by Colaboratory.

Original file is located at
    https://colab.research.google.com/drive/1_2W9-AGesIiGsa5IynWemzBKQgR6KKFS
"""

#CPT 115 MATHEMATICAL METHODS FOR COMPUTER SCIENCE
#Assignment 1
#Group 4

# coding=gbk
from PIL import Image
import numpy as np
# import scipy
import matplotlib.pyplot as plt

# ImageToMatrix function definition
def ImageToMatrix(filename):
    # read the image
    im = Image.open(filename)   #read the image
    display(im)   #display the image
    # show the image
    # im.show()  
    width,height = im.size  #get the size of image
    im = im.convert("L") 
    data = im.getdata()
    data = np.matrix(data,dtype='float')  #convert image to matrix
    new_data = np.reshape(data,(height,width))  #reshape the size of matrix
    return new_data

filename = '/2020-10-09 (1).png'
im = ImageToMatrix(filename) #convert image to matrix
# print detail of image
print()
print('Type of image: ',type(im))
print('Shape of the image:{}'.format(im.shape))
print('Image Height: {}'.format(im.shape[0]))
print('Image width: {}'.format(im.shape[1]))
print('Dimension of Image: {}'.format(im.ndim))
print('Image size: {}'.format(im.size))
print()


# generate a key in matrix form
key=np.random.random_integers(10,size=(im.shape[1],im.shape[1]))  
# key = np.matrix(key,dtype='float')
inverse_key=np.linalg.inv(key)  # inverse the key

# "encrypt" store the matrix of encrypted image
encrypt = im * key  # multiply the image's matrix with key(matrix)

# "encrypt_im" is the encrypted image
# convert encrypted image's matrix into encrypted image
encrypt_im = Image.fromarray(encrypt.astype(np.uint8)) 

# print dectypted image
print()
print('Display encrypted image:')
display(encrypt_im) 

# "decrypt" is the matrix of decrypted image
# decrypt the image by multiplying the encrypted image's matrix with the inverse of key(matrix)
decrypt = encrypt * inverse_key    

# convert the matrix of decrypted image into image
decrypt_im = Image.fromarray(decrypt.astype(np.uint8))  
# display the decrypted image
print()
print('display decrypted image:')
display(decrypt_im)