46 lines
1.6 KiB
Python
46 lines
1.6 KiB
Python
from __future__ import annotations
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from Cryptodome.Cipher import AES
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from Cryptodome.Util import Counter
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from librespot.audio.storage import ChannelManager
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from librespot.structure import AudioDecrypt
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import io
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import time
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class AesAudioDecrypt(AudioDecrypt):
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audio_aes_iv = b'r\xe0g\xfb\xdd\xcb\xcfw\xeb\xe8\xbcd?c\r\x93'
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cipher = None
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decrypt_count = 0
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decrypt_total_time = 0
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iv_int = int.from_bytes(audio_aes_iv, "big")
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iv_diff = 0x100
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key: bytes
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def __init__(self, key: bytes):
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self.key = key
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def decrypt_chunk(self, chunk_index: int, buffer: bytes):
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new_buffer = io.BytesIO()
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iv = self.iv_int + int(ChannelManager.chunk_size * chunk_index / 16)
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start = time.time_ns()
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for i in range(0, len(buffer), 4096):
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cipher = AES.new(key=self.key,
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mode=AES.MODE_CTR,
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counter=Counter.new(128, initial_value=iv))
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count = min(4096, len(buffer) - i)
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decrypted_buffer = cipher.decrypt(buffer[i:i + count])
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new_buffer.write(decrypted_buffer)
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if count != len(decrypted_buffer):
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raise RuntimeError(
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"Couldn't process all data, actual: {}, expected: {}".
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format(len(decrypted_buffer), count))
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iv += self.iv_diff
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self.decrypt_total_time += time.time_ns() - start
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self.decrypt_count += 1
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new_buffer.seek(0)
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return new_buffer.read()
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def decrypt_time_ms(self):
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return 0 if self.decrypt_count == 0 else int(
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(self.decrypt_total_time / self.decrypt_count) / 1000000)
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