#!/usr/bin/python3

from Crypto.Cipher import AES

import getopt

import sys

import os

class AESCipher:

def __init__(self, key, iv):

self.key = key

self.iv = iv

def encrypt(self, raw):

"""

Returns encrypted block

"""

cipher = AES.new(self.key, AES.MODE_ECB)

encrypted = cipher.encrypt(raw)

return encrypted

def decrypt(self, enc):

"""

Requires encrypted block, returns decrypted block

"""

cipher = AES.new(self.key, AES.MODE_ECB)

decrypted = cipher.decrypt(enc)

return decrypted

#key = b'abcdefghijklmnop'

key_hex = os.environ.get("KEY")

if key_hex is None:

print("Error: FESTIVAL_MIDI_KEY environment variable not set")

sys.exit(1)

key = bytearray.fromhex(key_hex)

iv = bytearray.fromhex("00000000000000000000000000000000") # null nonce because that's just what they do when they ECB

arglist = sys.argv[1:]

options = "dev"

long_options = ["decrypt","encrypt","verbose"]

cryptor = False

verbose = False

try:

opts, args= getopt.getopt(arglist,options,long_options)

for curArg,curVal in opts:

if curArg in ("-d","--decrypt"):

if cryptor == True:

print("Cannot do both encryption and decryption simultaneously")

quit()

encrypt = False

cryptor = True

elif curArg in ("-e","--encrypt"):

if cryptor == True:

print("Cannot do both encryption and decryption simultaneously")

quit()

encrypt = True

cryptor = True

elif curArg in ("-v","--verbose"):

verbose = True

except getopt.error as err:

print(err)

quit()

if (len(args) == 0) | (len(opts) == 0):

print(os.path.basename(sys.argv[0]), "v1.0\n")

print("Usage: [-d/-e] [-v] <file>\n")

print("-d / --decrypt: decrypt FNF .dat to .mid")

print("-e / --encrypt: encrypt .mid to FNF .dat")

print("-v / --verbose: verbose output")

print("<file>: input file to encrypt or decrypt")

if cryptor == False:

print("Must use one of either -e/--encrypt or -d/--decrypt")

quit()

infile = args[0]

infilename, infileext = os.path.splitext(infile)

if encrypt:

outfile = infilename + ".dat"

else:

outfile = infilename + ".mid"

try:

encfile = open(infile, "rb")

except FileNotFoundError as exc:

print(infile + ": file not found")

quit()

decfile = open(outfile, "wb")

if verbose:

print("AES key is",key.hex())

if encrypt:

print("Encrypting",os.path.basename(infile),"to",os.path.basename(outfile))

else:

print("Decrypting",os.path.basename(infile),"to",os.path.basename(outfile))

c = AESCipher(key, iv)

count=0

while True:

block = encfile.read(16)

if block:

count += 1

elif not block:

break

if len(block) < 16:

blockpad = 16 - len(block)

print("Final block is",len(block),"bytes, adding",blockpad,"padding bytes")

tempblock = bytearray(16)

for b in range(0,len(block)):

tempblock[b] = block[b]

block = bytes(tempblock)

if encrypt:

ptxt = c.encrypt(block)

if verbose:

print("Block",count,": DEC:",block.hex(),"ENC:",ptxt.hex())

else:

ptxt = c.decrypt(block)

if verbose:

print("Block",count,": ENC:",block.hex(),"DEC:",ptxt.hex())

decfile.write(ptxt)

if encrypt:

print("Encrypted",count,"blocks")

if not encrypt:

print("Decrypted",count,"blocks")

print("Closing files...")

encfile.close()

decfile.close()

print("Done!")