Change Directory

librespot/crypto/CipherPair.py

@@ -0,0 +1,62 @@
+from librespot.crypto.Packet import Packet
+from librespot.crypto.Shannon import Shannon
+import struct
+
+
+class CipherPair:
+    send_cipher: Shannon
+    receive_cipher: Shannon
+    send_nonce = 0
+    receive_nonce = 0
+
+    def __init__(self, send_key: bytes, receive_key: bytes):
+        # self.send_cipher = Shannon()
+        # self.send_cipher.key(send_key)
+        self.send_cipher = Shannon(send_key)
+        self.send_nonce = 0
+
+        # self.receive_cipher = Shannon()
+        # self.receive_cipher.key(receive_key)
+        self.receive_cipher = Shannon(receive_key)
+        self.receive_nonce = 0
+
+    def send_encoded(self, conn, cmd: bytes, payload: bytes):
+        self.send_cipher.nonce(self.send_nonce)
+        self.send_nonce += 1
+
+        buffer = b""
+        buffer += cmd
+        buffer += struct.pack(">H", len(payload))
+        buffer += payload
+
+        buffer = self.send_cipher.encrypt(buffer)
+
+        # mac = self.send_cipher.finish(bytes(4))
+        mac = self.send_cipher.finish(4)
+
+        conn.write(buffer)
+        conn.write(mac)
+        conn.flush()
+
+    def receive_encoded(self, conn) -> Packet:
+        try:
+            self.receive_cipher.nonce(self.receive_nonce)
+            self.receive_nonce += 1
+
+            header_bytes = self.receive_cipher.decrypt(conn.read(3))
+
+            cmd = struct.pack(">s", bytes([header_bytes[0]]))
+            payload_length = (header_bytes[1] << 8) | (header_bytes[2] & 0xff)
+
+            payload_bytes = self.receive_cipher.decrypt(
+                conn.read(payload_length))
+
+            mac = conn.read(4)
+
+            expected_mac = self.receive_cipher.finish(4)
+            if mac != expected_mac:
+                raise RuntimeError()
+
+            return Packet(cmd, payload_bytes)
+        except IndexError:
+            raise RuntimeError()