diff --git a/cognises/requirements.txt b/cognises/requirements.txt
index b0735dd..0a43a4d 100644
--- a/cognises/requirements.txt
+++ b/cognises/requirements.txt
@@ -6,7 +6,7 @@ chardet==3.0.4
 click==6.7
 cryptography==1.7.2
 docutils==0.14
-ecdsa==0.13
+ecdsa==0.13.3
 enum34==1.1.6
 Flask==1.0.1
 future==0.16.0