#-*- coding: utf-8 -*-
# (c) 2015 Anders Andersen
# See http://www.cs.uit.no/~aa/dist/tools/py/COPYING for details
from sys import argv, stdin, stdout
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization, hashes
from cryptography.hazmat.primitives.asymmetric import padding
# argv[1]: RSA key file name (reads)
# argv[2]: AES key file name (reads)
# argv[3]: password (optional)
# stdin: input data
# stdout: output data
if len(argv) > 2:
# Password, if any
passwd = None
if len(argv) > 3:
passwd = argv[3].encode()
# Read RSA key
frsakey = open(argv[1], "rb")
rsakey = serialization.load_pem_private_key(
frsakey.read(),
password=passwd,
backend=default_backend())
frsakey.close()
# Read and decrypt AES key
faeskey = open(argv[2], "rb")
aesinfo = rsakey.decrypt(
faeskey.read(),
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA1()),
algorithm=hashes.SHA1(),
label=None))
irv = aesinfo[:algorithms.AES.block_size//8]
aeskey = aesinfo[algorithms.AES.block_size//8:]
# Create AES cipher
cipher = Cipher(algorithms.AES(aeskey), modes.CTR(irv), backend=default_backend())
decryptor = cipher.decryptor()
# Read ciphertext from stdin and write plaintext to stdout
while True:
data = stdin.buffer.read()
if not data: break
stdout.buffer.write(decryptor.update(data) + decryptor.finalize())