diff --git a/.gitignore b/.gitignore
index aa20c5709..09e127d85 100644
--- a/.gitignore
+++ b/.gitignore
@@ -39,6 +39,7 @@ updates_key.pem
 *.part
 *.ytdl
 *.swp
+*.webm
 test/local_parameters.json
 .tox
 youtube-dl.zsh
diff --git a/haruhi_dl/extractor/youtube.py b/haruhi_dl/extractor/youtube.py
index 9ff089cd8..a2b98c72c 100644
--- a/haruhi_dl/extractor/youtube.py
+++ b/haruhi_dl/extractor/youtube.py
@@ -1101,13 +1101,12 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
     def _decrypt_signature_protected(self, s):
         a = list(s)
         a.reverse()
-        a = a[2:]
-        a = self.mess(a, 65)
-        a = a[2:]
+        a = self.mess(a, 10)
         a.reverse()
-        a = a[3:]
-        a.reverse()
-        a = self.mess(a, 2)
+        a = a[1:]
+        a = self.mess(a, 13)
+        a = a[2:]
+        a = self.mess(a, 15)
         return "".join(a)
 
     def _get_subtitles(self, video_id, webpage):
diff --git a/haruhi_dl/version.py b/haruhi_dl/version.py
index 0982e8834..7f8b05ec9 100644
--- a/haruhi_dl/version.py
+++ b/haruhi_dl/version.py
@@ -1,3 +1,3 @@
 from __future__ import unicode_literals
 
-__version__ = '2020.11.16'
+__version__ = '2020.11.20'