🌟 Re-add all project files.

1 files changed, 53 insertions, 0 deletions

diff --git a/tidal_dl_ng/helper/decryption.py b/tidal_dl_ng/helper/decryption.py
new file mode 100644
index 0000000..2fa2ec0
--- /dev/null
+++ b/tidal_dl_ng/helper/decryption.py
@@ -0,0 +1,53 @@
+import base64
+
+from Crypto.Cipher import AES
+from Crypto.Util import Counter
+
+
+def decrypt_security_token(security_token: str) -> (str, str):
+    """
+    Decrypts security token into key and nonce pair
+
+    security_token should match the securityToken value from the web response
+    """
+
+    # Do not change this
+    master_key = "UIlTTEMmmLfGowo/UC60x2H45W6MdGgTRfo/umg4754="
+
+    # Decode the base64 strings to ascii strings
+    master_key = base64.b64decode(master_key)
+    security_token = base64.b64decode(security_token)
+
+    # Get the IV from the first 16 bytes of the securityToken
+    iv = security_token[:16]
+    encrypted_st = security_token[16:]
+
+    # Initialize decryptor
+    decryptor = AES.new(master_key, AES.MODE_CBC, iv)
+
+    # Decrypt the security token
+    decrypted_st = decryptor.decrypt(encrypted_st)
+
+    # Get the audio stream decryption key and nonce from the decrypted security token
+    key = decrypted_st[:16]
+    nonce = decrypted_st[16:24]
+
+    return key, nonce
+
+
+def decrypt_file(path_file_encrypted: str, path_file_destination: str, key: str, nonce: str) -> None:
+    """
+    Decrypts an encrypted MQA file given the file, key and nonce
+    """
+
+    # Initialize counter and file decryptor
+    counter = Counter.new(64, prefix=nonce, initial_value=0)
+    decryptor = AES.new(key, AES.MODE_CTR, counter=counter)
+
+    # Open and decrypt
+    with open(path_file_encrypted, "rb") as f_src:
+        audio_decrypted = decryptor.decrypt(f_src.read())
+
+        # Replace with decrypted file
+        with open(path_file_destination, "wb") as f_dst:
+            f_dst.write(audio_decrypted)