From facd01b52e6b7122fb3413345fef2d5d08b1f377 Mon Sep 17 00:00:00 2001
From: Fijxu <fijxu@nadeko.net>
Date: Sun, 16 Mar 2025 19:54:40 -0300
Subject: [PATCH] feat: add support for encrypted query parameters

Related:

- https://git.nadeko.net/Fijxu/http3-ytproxy/commit/6bd0f28d779596c2f7439395818db0c46698d5f0
- https://git.nadeko.net/Fijxu/invidious-companion/commit/7eae31613e6d674dc5122a980e0ac6cc2d57ae2b
---
 src/invidious/helpers/utils.cr         | 23 +++++++++++++++++++++++
 src/invidious/routes/video_playback.cr |  5 +++++
 2 files changed, 28 insertions(+)

diff --git a/src/invidious/helpers/utils.cr b/src/invidious/helpers/utils.cr
index 7aacfe7e..a2f95eca 100644
--- a/src/invidious/helpers/utils.cr
+++ b/src/invidious/helpers/utils.cr
@@ -384,6 +384,29 @@ def parse_link_endpoint(endpoint : JSON::Any, text : String, video_id : String)
   return text
 end
 
+def decrypt_ecb_without_salt(data, key)
+  cipher = OpenSSL::Cipher.new("aes-128-ecb")
+  cipher.decrypt
+  cipher.key = key
+  cipher.padding = false
+
+  io = IO::Memory.new
+  io.write(cipher.update(data))
+  io.write(cipher.final)
+  io.rewind
+
+  data_ = io.to_s
+  padding = data_[-1].ord
+
+  return data_[0...(data_.bytesize - padding)]
+end
+
+def video_playback_decrypt(data)
+  data = Base64.decode(data)
+  decrypted_query = decrypt_ecb_without_salt(data, CONFIG.invidious_companion_key)
+  return decrypted_query
+end
+
 def encrypt_ecb_without_salt(data, key)
   cipher = OpenSSL::Cipher.new("aes-128-ecb")
   cipher.encrypt
diff --git a/src/invidious/routes/video_playback.cr b/src/invidious/routes/video_playback.cr
index 19342e4e..3c1b85a6 100644
--- a/src/invidious/routes/video_playback.cr
+++ b/src/invidious/routes/video_playback.cr
@@ -3,6 +3,11 @@ module Invidious::Routes::VideoPlayback
   def self.get_video_playback(env)
     locale = env.get("preferences").as(Preferences).locale
     query_params = env.params.query
+
+    if query_params["enc"]? == "yes"
+      query_params = URI::Params.parse(video_playback_decrypt(query_params["data"]))
+    end
+
     array = UInt8[0x78, 0]
     protobuf = Bytes.new(array.size)
     array.each_with_index do |byte, index|