diff --git a/Chapter05/cryptocurrency_application/requirements.txt b/Chapter05/cryptocurrency_application/requirements.txt
index 7e038fe..27f427e 100644
--- a/Chapter05/cryptocurrency_application/requirements.txt
+++ b/Chapter05/cryptocurrency_application/requirements.txt
@@ -1,3 +1,3 @@
 sanic==0.7.0
 pycryptodome==3.4.11
-ecdsa==0.13
+ecdsa==0.13.3