Fix: updated required cryptography version to 2.4.2 to resolve #6509

requirements.txt

@@ -20,7 +20,7 @@ chardet==3.0.4            # via requests
 click==6.7
 colorama==0.3.9
 contextlib2==0.5.5
-cryptography==1.9
+cryptography==2.4.2
 defusedxml==0.5.0         # via python3-openid
 docutils==0.14            # via botocore
 et-xmlfile==1.0.1         # via openpyxl