diff --git a/devscripts/youtube_genalgo.py b/devscripts/youtube_genalgo.py
index 01583e4325..b168cea77b 100644
--- a/devscripts/youtube_genalgo.py
+++ b/devscripts/youtube_genalgo.py
@@ -10,7 +10,7 @@
     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$^&*()_-+={[]}|:;?/>.<",
      "!?;:|}][{=+-_)(*&^$#@/MNBVCXZASqFGHJKLPOIUYTREWQ0987654321mnbvcxzasdfghjklpoiuytr"),
     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[|};?/>.<",
-     "ertyuioplkjhgfdqazxcvbnm1234567890QWERT}UIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[|/;?Y"),
+     "ertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!/#$%^&*()_-+={[|};?@"),
     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[};?/>.<",
      "{>/?;}[.=+-_)(*&^%$#@!MqBVCXZASDFwHJKLPOIUYTREWQ0987654321mnbvcxzasdfghjklpoiuytr"),
     ("qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[};?>.<",
diff --git a/test/test_youtube_sig.py b/test/test_youtube_sig.py
index 5f23fababd..e87b6259be 100755
--- a/test/test_youtube_sig.py
+++ b/test/test_youtube_sig.py
@@ -22,32 +22,32 @@ def test_88(self):
         wrong = "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[]}|:;?/>.<"
         right = "J:|}][{=+-_)(*&;%$#@>MNBVCXZASDFGH^KLPOIUYTREWQ0987654321mnbvcxzasdfghrklpoiuytej"
         self.assertEqual(sig(wrong), right)
- 
+
     def test_87(self):
         wrong = "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$^&*()_-+={[]}|:;?/>.<"
         right = "!?;:|}][{=+-_)(*&^$#@/MNBVCXZASqFGHJKLPOIUYTREWQ0987654321mnbvcxzasdfghjklpoiuytr"
         self.assertEqual(sig(wrong), right)
- 
+
     def test_86(self):
         wrong = "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[|};?/>.<"
-        right = "ertyuioplkjhgfdqazxcvbnm1234567890QWERT}UIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[|/;?Y"
+        right = "ertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!/#$%^&*()_-+={[|};?@"
         self.assertEqual(sig(wrong), right)
- 
+
     def test_85(self):
         wrong = "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[};?/>.<"
         right = "{>/?;}[.=+-_)(*&^%$#@!MqBVCXZASDFwHJKLPOIUYTREWQ0987654321mnbvcxzasdfghjklpoiuytr"
         self.assertEqual(sig(wrong), right)
- 
+
     def test_84(self):
         wrong = "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!@#$%^&*()_-+={[};?>.<"
         right = "<.>?;}[{=+-_)(*&^%$#@!MNBVCXZASDFGHJKLPOIUYTREWe098765432rmnbvcxzasdfghjklpoiuyt1"
         self.assertEqual(sig(wrong), right)
- 
+
     def test_83(self):
         wrong = "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKJHGFDSAZXCVBNM!#$%^&*()_+={[};?/>.<"
         right = "D.>/?;}[{=+_)(*&^%$#!MNBVCXeAS<FGHJKLPOIUYTREWZ0987654321mnbvcxzasdfghjklpoiuytrQ"
         self.assertEqual(sig(wrong), right)
- 
+
     def test_82(self):
         wrong = "qwertyuioplkjhgfdsazxcvbnm1234567890QWERTYUIOPLKHGFDSAZXCVBNM!@#$%^&*(-+={[};?/>.<"
         right = "Q>/?;}[{=+-(*<^%$#@!MNBVCXZASDFGHKLPOIUY8REWT0q&7654321mnbvcxzasdfghjklpoiuytrew9"
diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index 8470c40e25..997278cabf 100644
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -139,7 +139,7 @@ def _decrypt_signature(self, s):
         elif len(s) == 87:
             return s[62] + s[82:62:-1] + s[83] + s[61:52:-1] + s[0] + s[51:2:-1]
         elif len(s) == 86:
-            return s[2:17] + s[0] + s[18:41] + s[79] + s[42:79] + s[82] + s[80:82] + s[41]
+            return s[2:63] + s[82] + s[64:82] + s[63]
         elif len(s) == 85:
             return s[76] + s[82:76:-1] + s[83] + s[75:60:-1] + s[0] + s[59:50:-1] + s[1] + s[49:2:-1]
         elif len(s) == 84: