It's better to put .asc or .gpg file into `/etc/apt/trusted.gpg.d``` like

sudo wget -O /etc/apt/trusted.gpg.d/docker.asc https://download.docker.com/linux/debian/gpg

instead of apt-key add

curl -s /etc/apt/trusted.gpg.d/docker.asc | sudo apt-key add -

man APT-KEY(8):

Note: Instead of using this command a keyring should be placed directly in the /etc/apt/trusted.gpg.d/ directory with a descriptive name and either "gpg" or "asc" as file extension.