Change Directory

librespot/audio/decrypt/AesAudioDecrypt.py

@@ -0,0 +1,49 @@
+from Crypto.Cipher import AES
+from Crypto.Util import Counter
+from librespot.audio.storage.ChannelManager import ChannelManager
+from librespot.audio.decrypt.AudioDecrypt import AudioDecrypt
+import time
+
+
+class AesAudioDecrypt(AudioDecrypt):
+    audio_aes_iv = bytes([
+        0x72, 0xe0, 0x67, 0xfb, 0xdd, 0xcb, 0xcf, 0x77, 0xeb, 0xe8, 0xbc, 0x64,
+        0x3f, 0x63, 0x0d, 0x93
+    ])
+    iv_int = int.from_bytes(audio_aes_iv, "big")
+    iv_diff = 0x100
+    cipher = None
+    decrypt_count = 0
+    decrypt_total_time = 0
+    key: bytes = None
+
+    def __init__(self, key: bytes):
+        self.key = key
+
+    def decrypt_chunk(self, chunk_index: int, buffer: bytes):
+        new_buffer = b""
+        iv = self.iv_int + int(ChannelManager.CHUNK_SIZE * chunk_index / 16)
+        start = time.time_ns()
+        for i in range(0, len(buffer), 4096):
+            cipher = AES.new(key=self.key,
+                             mode=AES.MODE_CTR,
+                             counter=Counter.new(128, initial_value=iv))
+
+            count = min(4096, len(buffer) - i)
+            decrypted_buffer = cipher.decrypt(buffer[i:i + count])
+            new_buffer += decrypted_buffer
+            if count != len(decrypted_buffer):
+                raise RuntimeError(
+                    "Couldn't process all data, actual: {}, expected: {}".
+                    format(len(decrypted_buffer), count))
+
+            iv += self.iv_diff
+
+        self.decrypt_total_time += time.time_ns()
+        self.decrypt_count += 1
+
+        return new_buffer
+
+    def decrypt_time_ms(self):
+        return 0 if self.decrypt_count == 0 else int(
+            (self.decrypt_total_time / self.decrypt_count) / 1000000)

librespot/audio/decrypt/AudioDecrypt.py

@@ -0,0 +1,6 @@
+class AudioDecrypt:
+    def decrypt_chunk(self, chunk_index: int, buffer: bytes):
+        pass
+
+    def decrypt_time_ms(self):
+        pass

librespot/audio/decrypt/NoopAudioDecrypt.py

@@ -0,0 +1,9 @@
+from librespot.audio.decrypt import AudioDecrypt
+
+
+class NoopAudioDecrypt(AudioDecrypt):
+    def decrypt_chunk(self, chunk_index: int, buffer: bytes):
+        pass
+
+    def decrypt_time_ms(self):
+        return 0

librespot/audio/decrypt/__init__.py

@@ -0,0 +1,3 @@
+from librespot.audio.decrypt.AesAudioDecrypt import AesAudioDecrypt
+from librespot.audio.decrypt.AudioDecrypt import AudioDecrypt
+from librespot.audio.decrypt.NoopAudioDecrypt import NoopAudioDecrypt