def set_stego_payload(self, filename: str, payload: bytes, key: str,
lsb: int):
max_payload = self.get_payload_size(lsb) - 8 - len(
filename.encode("latin-1"))
if len(payload) > max_payload:
raise SteganographyException("Payload too big")
if key != "":
vigenere = Vigenere(Vigenere.EXTENDED, key=key.encode("utf-8"))
payload = vigenere.encrypt(payload)
random.seed(sum([ord(key[i]) for i in range(0, len(key), 2)]))
else:
random.seed(key)
pixels_count = self._base_image.width * self._base_image.height
seq = [i for i in range(pixels_count)]
random.shuffle(seq)
full_payload = pack("HHI", 0x1337, len(filename), len(payload))
full_payload += filename.encode("latin-1")
full_payload += payload
full_payload = BitArray(bytes=full_payload).bin
len_payload = self._roundup(len(full_payload), lsb)
full_payload = full_payload.ljust(len_payload, '0')
i = 0
bit_mask = (1 << lsb) - 1
# make copy list pixel
self._payloaded_pixel = list(self._base_image.getdata()).copy()
for pos in seq:
if i >= len(full_payload) / lsb:
break
temp_pixel = self._payloaded_pixel[pos]
if type(temp_pixel) == tuple:
list_pixel = []
for j in range(len(temp_pixel)):
temp_each_pixel = temp_pixel[j]
temp_each_pixel = self._put_bits(
temp_each_pixel, bit_mask,
full_payload[lsb * i:lsb * (i + 1)])
list_pixel.append(temp_each_pixel)
i += 1
temp_pixel = tuple(list_pixel)
else:
temp_pixel = self._put_bits(
temp_pixel, bit_mask, full_payload[lsb * i:lsb * (i + 1)])
i += 1
self._payloaded_pixel[pos] = temp_pixel
