diff --git a/requirements.txt b/requirements.txt
index cefdabc..77f7331 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,7 +4,7 @@ certifi==2018.8.24
 chardet==3.0.4
 Click==7.0
 dill==0.2.5
-ecdsa==0.13
+ecdsa==0.13.3
 enum==0.4.7
 Flask==0.12.2
 flask-apispec==0.7.0