mysql PPA - invalid signature

The error you are seeing indicates that your key is expired.

You can list all keys on your system with the command sudo apt-key list if you wish to narrow the output you can always pipe the output through grep expired to obtain just a list of the expired keys.

For each expired key, issue the command sudo apt-key adv --keyserver keys.gnupg.net --recv-keys [KEY] where [KEY] is related to the number in question or in this case:

8C718D3B5072E1F5

sudo apt-key adv --keyserver keys.gnupg.net --recv-keys 8C718D3B5072E1F5

keys.gnupg.net refers to the SKS keyserver pool, a number of PGP keyservers run by organisations and volunteers.

You can also search for the key via web interface at keys.gnupg.net

where you'll get a page like this:

Entering the key from the EXPKEYSIG preceded by 0x in the search box and searching should return results similar to this:

To the best of my knowledge the 8 hex digits is the short version (public key) you need to obtain an updated key with the command

sudo apt-key adv --keyserver keys.gnupg.net --recv-keys 5072E1F5

Sources:

• https://linux-audit.com/how-to-solve-an-expired-key-keyexpired-with-apt/
• https://stackoverflow.com/questions/44768657/cannot-add-keys-from-keys-gnupg-net

Get the latest (not expired) MySQL APT repository from: https://dev.mysql.com/downloads/repo/apt/

Currently: https://repo.mysql.com//mysql-apt-config_0.8.13-1_all.deb

wget https://repo.mysql.com/mysql-apt-config_0.8.13-1_all.deb
sudo dpkg -i mysql-apt-config_0.8.13-1_all.deb
sudo apt-get update
sudo apt install mysql-server

try running $sudo apt-key adv --keyserver keys.gnupg.net --recv-keys 5072E1F5

source: https://bugs.mysql.com/bug.php?id=85029