diff --git a/requirements.txt b/requirements.txt
index f6b17ef27..13b262c50 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 certifi
-cryptography
+cryptography!=3.4
 # only telegram.ext: # Keep this line here; used in setup(-raw).py
 tornado>=5.1
 APScheduler==3.6.3