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def byte_pair_decompress(bytes):
    bytes = iter(bytes)
    escape_value = bytes.next()
    entry_count = ord(bytes.next())
    pair_expansion = dict(
        (bytes.next(), (bytes.next(), bytes.next())
        for _ in xrange(entry_count)
    )
    if bytes.next() != '\x5b':
        raise ValueError('Bad magic after map')
    for value in bytes:
        if value == escape_value:
            yield bytes.next()
        else:
            for value in pair_expansion.get(value, [value]):
                yield value

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from javax.crypto import Cipher

cipher = Cipher.getInstance("AES/CTS/NoPadding")

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#!/usr/bin/env python
# -*- coding: utf-8 -*-
import sys
from hashlib import md5
from struct import Struct
from Crypto.Cipher import AES


KEYS = [
    '\x1d\xe5\xfa\xb8\x81\x91\x00\x84\x11\xaf\x53\xdd\xe4\x89\xea\xfd',
    '\xa9\xdc\x0e\xf0\x28\x67\x91\xac\xc9\x13\x86\x5d\x2d\xf8\x20\x99',
    '\x1a\xa8\x80\xb5\x44\x11\xf1\x19\x0c\xca\x3d\xe8\x77\x41\x37\x89',
    '\x45\x68\x70\x98\x7a\xcd\xeb\xbb\xbd\xed\xa8\x03\x98\x73\x40\x24',
]
HEADER_STRUCT = Struct('<iib16s')
HEADER_SIZE = 0x28
PAYLOAD_HEADER_STRUCT = Struct('<HBBH')


def byte_pair_decompress(bytes):
    escape_value = bytes.next()
    entry_count = ord(bytes.next())
    pair_expansion = dict(
        (bytes.next(), (bytes.next(), bytes.next()))
        for _ in xrange(entry_count)
    )
    if bytes.next() != '\x5b':
        raise ValueError('Bad magic after map')
    for value in bytes:
        if value == escape_value:
            yield bytes.next()
        else:
            for value in pair_expansion.get(value, [value]):
                yield value


def unpack_header(data, expected_magic, check_key_number=True):
    magic, size, key_number, expected_md5 = HEADER_STRUCT.unpack(
        data[:HEADER_STRUCT.size]
    )
    if magic != expected_magic:
        raise ValueError('Bad magic')
    if check_key_number:
        if not (0 <= key_number < len(KEYS)):
            raise ValueError('Bad key number (0-%d expected)' % len(KEYS) - 1)
    return size, key_number, expected_md5


def extract_config(in_file=sys.stdin, out_file=sys.stdout):
    init_vector = in_file.read(16)
    cipher = AES.new(KEYS[0], AES.MODE_CBC, init_vector) # BUG Mode is incorrect.
    
    header = cipher.decrypt(in_file.read(HEADER_SIZE))
    size, key_number, expected_md5 = unpack_header(header, 0x59585756)
    
    body = in_file.read(size)
    if expected_md5 != md5(body).digest():
        raise ValueError('Body MD5 does not match')
    
    cipher = AES.new(KEYS[key_number], AES.MODE_CBC, body[:16]) # BUG See above.
    payload = cipher.decode(body[16:])
    
    size, _key_number, expected_md5 = unpack_header(payload, 0x48464442, False)
    if expected_md5 != md5(payload[HEADER_SIZE:]).digest():
        raise ValueError('Payload MD5 does not match')
    
    data_offset = HEADER_SIZE + PAYLOAD_HEADER_STRUCT.size
    magic, levels, size_high, size_low = PAYLOAD_HEADER_STRUCT.unpack(
        payload[HEADER_SIZE:data_offset]
    )
    if magic != 0x6562:
        raise ValueError('Byte-pair compression magic does not match')
    compressed_size = size_high << 16 | size_low
    
    bytes = payload[data_offset:compressed_size]
    for _ in xrange(levels):
        bytes = byte_pair_decompress(bytes)
    
    out_file.writelines(bytes)


def main():
    extract_config()


if __name__ == '__main__':
    main()

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    header = cipher.decrypt(in_file.read(HEADER_SIZE))
ValueError: Input strings must be a multiple of 16 in length