def encrypt(key, filename):
	chunksize = 64*1024
	#print filename
	#print "4th time: ", key
	outputFile = "(encrypted)"+filename
	filesize = str(os.path.getsize(filename)).zfill(16)
	IV = ''

	for i in range(16):
		IV += chr(random.randint(0, 0xFF))

	encryptor = AES.new(key, AES.MODE_CBC, IV)

	with open(filename, 'rb') as infile:
		with open(outputFile, 'wb') as outfile:
			outfile.write(filesize)
			outfile.write(IV)
			
			while True:
				chunk = infile.read(chunksize)
				
				if len(chunk) == 0:
					break
				elif len(chunk) % 16 != 0:
					chunk += ' ' * (16 - (len(chunk) % 16))

				outfile.write(encryptor.encrypt(chunk))