diff --git a/build/Dockerfile b/build/Dockerfile
index dff44cc..1c0629a 100644
--- a/build/Dockerfile
+++ b/build/Dockerfile
@@ -32,6 +32,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 
 # Copy bash scripts
 COPY gpgparams entrypoint.sh /protonmail/
+COPY generate_new_certs.sh /root/generate_new_certs.sh
 WORKDIR /protonmail/
 
 # Copy protonmail
diff --git a/scripts/generate_new_certs.sh b/scripts/generate_new_certs.sh
new file mode 100644
index 0000000..97715a9
--- /dev/null
+++ b/scripts/generate_new_certs.sh
@@ -0,0 +1,22 @@
+#!/bin/sh
+if [ -z "$1" ]; then
+  echo "Please add the hostname of the Docker Container Name where the Container Should Create a Cert for"
+  echo "like: $0 protonmail-bridge"
+  exit 1
+fi
+
+# 1. choose the hostname(s) you will actually type into your mail client
+HOSTS="$1,localhost,127.0.0.1"
+
+# 2. build the openssl SAN string automatically
+SAN=$(echo "$HOSTS" | tr ',' '\n' \
+  | sed -e 's/^[0-9.]*$/IP:&/' -e 's/^[^0-9.]*$/DNS:&/' \
+  | paste -sd,)
+
+# 3. generate key + cert in one shot
+openssl req -newkey rsa:2048 -nodes -keyout key.pem -x509 -days 3650 \
+  -out cert.pem -subj '/CN=protonmail-bridge' \
+  -addext "subjectAltName=$SAN"
+
+# 4. quick sanity-check
+openssl x509 -in cert.pem -text -noout | grep -A1 "Subject Alternative"