MIE - Multiplicative Inverse Encryption

An image encryption algorithm that makes use of GF(2⁸) modular arithmetic. The function has been implemented in both C++ and Python.

Samples

Input Image	Encrypted Image	Decrypted Image

About the algorithm

The MIE algorithm makes use of 2⁸ modular arithmetic. Therefore, the encryption and decryption of the image file requires only one function.

i.e., encrypt(encrypt(value)) = value

Algorithm

1. Read the image file and convert it to an array of pixels.
2. For every pixel of the image, find the Modular Multiplicative Inverse of the RGB values and update it in the array.
3. Save the encrypted/decrypted pixel values as image

Prerequisites

C++

• The MIE-CPP module uses STB libraries for reading and writing files.

Python

• The MIE-Python module uses OpenCV and Wand packages, so make sure it is installed before trying to use the MIE module.
• Also install: ImageMagick and GhostScript as they are prequisites for Wand.

Usage

C++

1. Compile and create an executable file of the program.
   • Ex: g++ encryptor.cpp -o encryptor.exe
2. Pass the command line arguments for the executable file to perform encryption/decryption.
   • i.e., encryptor.exe -E input.png output.png
   • Usage: <FILE.exe> ((-E/-e/encrypt)/(-D/-d/decrypt)) <INPUT_FILENAME> <OUTPUT_FILENAME>

Python

1. Import the MIE.py file
2. Instantiate the MIE or MIE_PDF files depending on your requirement
3. MIE
   1. Load the image using the MIE.loadImage() method
   2. Encrypt/Decrypt the image using the MIE.encrypt() or MIE.decrypt() methods
   3. Save the image using the MIE.saveImage() method
4. MIE_PDF
   1. Load the PDF using the MIE.getImages() method
   2. Encrypt/Decrypt the PDF using the MIE.encryptImages() or MIE.decryptImages() methods
   3. The encrypted PDF will be saved automatically
5. End

TODO

• Implement own functions for reading/writing image files.
• Pair with another algorithm to make the encryption secure and robust.