Dear Fred, Excellent question; I have re-used the bash script from my previous article which is a bit unfortunate. Because we are not running the Mosquitto broker in Ubuntu the copy part is not valid any more. I have updated the bash script and also added a bit of text in the "Docker compose and folder structure" section. The script will generate the certs to the working directory, You need to create the folder structure on your own. The keys are in the volume that you mount to your Docker container. I hope this clarifies things, otherwise I will gladly add some additional text. Thank you for reading the article and your kind words!