advanced-encryption-standard

decrypt.py

from Cryptodome.Cipher import AES
import argparse
import traceback

parser = argparse.ArgumentParser()
parser.add_argument("-f", dest="FILE_PATH", required=True, help="Encrypted file path")
parser.add_argument("-k", dest="KEY_PATH", required=True, help="Key file path")
parser.parse_args()
args = parser.parse_args()

key = open(args.k, "rb").read()
data = open(args.f, "rb")
nonce, tag, ciphertext = [ data.read(x) for x in (16, 16, -1) ]

print("Decrypting message...")
try:
    cipher = AES.new(key, AES.MODE_EAX, nonce)
    data = cipher.decrypt_and_verify(ciphertext, tag)
    print("Message: ", repr(data.decode('UTF-8')))
except Exception:
    print("Incorrect decryption: ")
    traceback.print_exc()

encrypt.py

from Cryptodome.Cipher import AES
from Cryptodome.Random import get_random_bytes
import argparse

parser = argparse.ArgumentParser()
parser.add_argument("-i", required=True, help="Input file path")
parser.add_argument("-o", default="encrypted-file.bin",
                    help="Path to save encryption file  (Default: encrypted-file.bin")
parser.add_argument("-k", default="encrypted-key.bin",
                    help="Path to save generated key (Default: encrypted-key.bin")
parser.parse_args()
args = parser.parse_args()
print(args)
file_in = args.i
file_out = args.o
key_out = args.i

data = open(file_in, "rb").read()
key = get_random_bytes(16)
cipher = AES.new(key, AES.MODE_EAX)
ciphertext, tag = cipher.encrypt_and_digest(data)

with open(file_out, "wb") as fout:
    for x in (cipher.nonce, tag, ciphertext):
        fout.write(x)
    print(f"Ciphertext written to '{file_out}'")

with open(key_out, "wb") as writer:
    writer.write(key)
    print(f"Key written to '{key_out}'")