diff --git a/Dockerfile-openresty b/Dockerfile-openresty
index 4595435..82f2158 100644
--- a/Dockerfile-openresty
+++ b/Dockerfile-openresty
@@ -5,7 +5,8 @@ RUN apt-get update && \
     apt-get install -y --no-install-recommends \
         git \
         curl \
-        luarocks
+        luarocks \
+        ca-certificates
 
 # Install Lua packages
 RUN luarocks install lua-resty-openidc