#-*- coding: utf-8 -*-
# (c) 2012 Anders Andersen
# See http://www.cs.uit.no/~aa/dist/tools/py/COPYING for details
from sys import argv, stdin, stdout
from Crypto import Random
from Crypto.PublicKey import RSA
from Crypto.Cipher import AES
from Crypto.Util import Counter
# 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]
# Read RSA key
frsakey = open(argv[1], "rb")
rsakey = RSA.importKey(frsakey.read(), passwd)
frsakey.close()
# Read and decrypt AES key
faeskey = open(argv[2], "rb")
aesinfo = rsakey.decrypt(faeskey.read())
irv = aesinfo[:AES.block_size]
aeskey = aesinfo[AES.block_size:]
# Create AES cipher
ctr = Counter.new(
AES.block_size*8,
initial_value=int.from_bytes(irv, "little"))
cipher = AES.new(aeskey, AES.MODE_CTR, counter=ctr)
# Read ciphertext from stdin and write plaintext to stdout
while True:
data = stdin.buffer.read()
if not data: break
stdout.buffer.write(cipher.decrypt(data))