mtk_geniezone_decrypt.py

from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes

KEY = bytes.fromhex("5c0e349a27dc46034c7b6744a378bd17")
IV = bytes.fromhex("a0b0924686447109f2d51dcddc93458a")

img = open("gz_a.bin", "rb")
img.seek(4)
length = int.from_bytes(img.read(4), "little")
img.seek(0x34)
offset = int.from_bytes(img.read(4), "little")

img.seek(offset)
ciphertext = img.read(length)

cipher = Cipher(algorithms.AES(KEY), modes.CTR(IV))
decryptor = cipher.decryptor()

plaintext = decryptor.update(ciphertext) + decryptor.finalize()

with open("gz_decrypted.bin", "wb") as outfile:
	outfile.write(plaintext)