#!/bin/bash
echo "Enter your ip address (Leave blank to use external IP):"
read myip

sudo apt update

if [$myip=""]
then
    $myip="$(dig +short myip.opendns.com @resolver1.opendns.com)"
fi

directory="$(pwd)"

echo "Creating keys..."
openssl ecparam -genkey -name secp384r1 -out privkey.pem
openssl ec -in privkey.pem -noout -text

echo "Writing config file..."
echo "[ req ]
prompt = no
encrypt_key = no
default_md = sha256
distinguished_name = dname
req_extensions = reqext

[ dname ]
CN = ${myip}
emailAddress = admin@example.com

[ reqext ]
subjectAltName = IP:${myip}" > "openssl.cnf"

echo "Creating signing request..."
openssl req -new -config openssl.cnf -key privkey.pem -out csr.pem

echo "Creating certificate..."
openssl x509 -req -in csr.pem -signkey privkey.pem -out certificate.crt -days 365

echo "Done"