numpy_encryption.py

# inspired by
# https://www.datasciencedata.com/2018/09/encryption-using-matrix-python.html

import numpy as np
from string import ascii_lowercase


ck = np.matrix = [[2, 1], [3, 2]]       # Encryption key
dk = np.matrix = [[2, -1], [-3, 2]]     # Decryption key
code_to_text = {}
text_to_code = {}
for number, letter in enumerate(ascii_lowercase):
    code_to_text[number] = letter
    text_to_code[letter] = number


def to_code(text):
    new_text = [text_to_code[s] for s in text]
    return np.asarray(new_text).reshape(2, len(new_text)//2)


def to_text(code_array):
    code_list = code_array.ravel().tolist()
    text_list = [code_to_text[num] for num in code_list]
    return ''.join(text_list)


password = 'arthur'                 # passwd
code_password = to_code(password)   # passwd to code
cipher = np.dot(ck, code_password)  # ciphered code
decipher = np.dot(dk, cipher)       # deciphered from ciphered code
text_password = to_text(decipher)   # passwd from code

print(password)                     # original passwd
print(text_password)                # deciphered passwd