Key Sharing is provided by DNS-SD, also known as Bonjour or Rendezvous. Enabling key sharing adds the local Passwords and Keys users' public key rings to the remote search dialog. Using these local key servers is generally faster than accessing remote servers.
Click Applications › Utilities › Passwords and Keys.
Click Edit › Preferences, then click the Key Servers tab.
Select Automatically synchronize modified keys with key servers.
Click Close.
Part III LibreOffice