pizza_arg_3.py

#!/usr/bin/env python3

# pizza_arg_3.py
# knocked together in record time (i.e., not very pythonic, readability prioritized, don't judge)
# by sfsdfd / david@djstein.com ... hope this helps the effort

# *** now translated into python3 ***

# using arc4 sample code from here:
# https://www.dlitz.net/software/pycrypto/api/current/Crypto.Cipher.ARC4-module.html
# ...and using twofish code from here:
# https://pypi.org/project/twofish/

# make sure you install both libraries first:
#    pip3 install --user pycrypto twofish
# ...you could use virtulenv if that's your thing, left as an exercise for the reader

# usage:
# pizza_arg_3.py test_arc4
#   - shows a brief demo of arc4 code to prove that it works
# pizza_arg_3.py test_twofish
#   - shows a brief demo of twofish code to prove that it works
# pizza_arg_3.py test_files
#   - saves some sample data to test_ciphertext, test_arc4_key, and test_twofish_key
# pizza_arg_3.py [ciphertext_filename] [arc4_key_filename] [twofish_key_filename]
#   - serial decoding: ciphertext --> arc4 (using key) --> twofish (using key)
# should be easy to reorganize the __main__ code if you want to do smth else, like
# reverse the decryption order, brute-force against various combinations of files, etc.

import codecs, os, sys
from Crypto.Cipher import ARC4
from twofish import Twofish

def encode_arc4(plaintext, arcfour_key):
	arc4 = ARC4.new(arcfour_key)
	return arc4.encrypt(plaintext)

def encode_arc4(plaintext, arcfour_key):
	arc4 = ARC4.new(arcfour_key)
	return arc4.encrypt(plaintext)

def decode_arc4(ciphertext, arcfour_key):
	arc4 = ARC4.new(arcfour_key)
	return arc4.decrypt(ciphertext)

def encode_twofish(plaintext, twofish_key):
	ciphertext = b''
	twofish = Twofish(twofish_key.encode())
	while len(plaintext) > 0:
		ciphertext = b''.join([ciphertext, twofish.encrypt(plaintext[:16].ljust(16).encode())])
		plaintext = plaintext[16:]
	return ciphertext

def decode_twofish(ciphertext, twofish_key):
	plaintext = ''
	twofish = Twofish(twofish_key.encode())
	while len(ciphertext) > 0:
		plaintext += twofish.decrypt(ciphertext[:16].ljust(16)).decode()
		ciphertext = ciphertext[16:]
	return plaintext

if __name__ == '__main__':
	try:
		if len(sys.argv) == 2 and sys.argv[1] == 'test_arc4':
			print('Testing arcfour:')
			arcfour_key = '12345'
			plaintext = 'The quick brown fox jumped over the lazy dogs.'
			print('Original plaintext: ' + plaintext)
			ciphertext = encode_arc4(plaintext, arcfour_key)
			print('Ciphertext:' + str(ciphertext))
			decoded_plaintext = decode_arc4(ciphertext, arcfour_key)
			print('Plaintext: ' + decoded_plaintext.decode('utf-8')); sys.exit(1)
		elif len(sys.argv) == 2 and sys.argv[1] == 'test_twofish':
			print('Testing twofish:')
			twofish_key = '67890'
			plaintext = 'The quick brown fox jumped over the lazy dogs.'
			print('Original plaintext: ' + plaintext)
			ciphertext = encode_twofish(plaintext, twofish_key)
			print('Ciphertext:' + str(ciphertext))
			decoded_plaintext = decode_twofish(ciphertext, twofish_key)
			print('Plaintext: ' + decoded_plaintext); sys.exit(1)
		elif len(sys.argv) == 2 and sys.argv[1] == 'test_files':
			plaintext = 'The quick brown fox jumped over the lazy dogs.'
			arcfour_key = '12345'
			twofish_key = '67890'
			twofish_encode = encode_twofish(plaintext, twofish_key)
			print('Twofish encode: ' + str(twofish_encode))
			arcfour_encode = encode_arc4(twofish_encode, arcfour_key)
			print('ARC4 encode: ' + str(arcfour_encode))
			with open('test_ciphertext', 'wb') as f:
				f.write(arcfour_encode)
			with codecs.open('test_arc4_key', 'w', 'utf-8') as f:
				f.write(arcfour_key + '\n')
			with codecs.open('test_twofish_key', 'w', 'utf-8') as f:
				f.write(twofish_key + '\n')
			print('Wrote test files.'); sys.exit(1)
		elif len(sys.argv) != 4:
			print('Usage: pizza_arg.py ciphertext_file arcfour_key_file twofish_key_file')
			sys.exit(1)
		if os.path.isfile(sys.argv[1]) is False:
			print('ciphertext_file: Invalid file name'); sys.exit(1)
		if os.path.isfile(sys.argv[2]) is False:
			print('arcfour_key_file: Invalid file name'); sys.exit(1)
		if os.path.isfile(sys.argv[3]) is False:
			print('twofish_key_file: Invalid file name'); sys.exit(1)
		print('Two-step decipher:')
		ciphertext = open(sys.argv[1], 'rb').read()
		arcfour_key = codecs.open(sys.argv[2], 'r', 'utf-8').read().strip()
		twofish_key = codecs.open(sys.argv[3], 'r', 'utf-8').read().strip()
		arcfour_decode = decode_arc4(ciphertext, arcfour_key)
		print('ARC4 decode: ' + str(arcfour_decode))
		twofish_decode = decode_twofish(arcfour_decode, str(twofish_key))
		print('Twofish decode: ' + str(twofish_decode))
	except Exception as e:
		print('Exception: ' + str(e))