Change SHA-implementation and make sure signature is correctly generated

Dockerfile

@@ -2,7 +2,7 @@ FROM ubuntu
 
 # Install prerequisites for Nginx compile
 RUN apt-get update && \
-    apt-get install -y wget tar gcc libpcre3-dev zlib1g-dev make libssl-dev liblua5.1-0 libluajit-5.1-dev curl jq
+    apt-get install -y wget tar gcc libpcre3-dev zlib1g-dev make libssl-dev liblua5.1-0 lua-bit32 libluajit-5.1-dev curl jq
 
 # Download Nginx
 WORKDIR /tmp
@@ -56,7 +56,7 @@ RUN ln -sf /dev/stdout /var/log/nginx/access.log \
 
 # Apply Nginx config
 ADD nginx.conf /etc/nginx/nginx.conf
-ADD sign.lua sha256.lua /tmp/lua/
+ADD sign.lua hmac.lua sha2.lua /tmp/lua/
 ADD start.sh /start.sh
 
 # Set default command