diff --git a/requirements.txt b/requirements.txt
index 33aa2ec..06e0ff4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,7 +10,7 @@ zeep
 chardet
 reportlab
 psycopg2-binary
-cryptography
+cryptography==3.4.8
 xmlsec
 segno