To enable your target image to use a signed package feed, you will need to add the following configuration to your conf/local.conf configuration file:

INHERIT += "sign_package_feed"
PACKAGE_FEED_GPG_NAME = "<key name>"
PACKAGE_FEED_GPG_PASSPHRASE_FILE = "<path/to/passphrase/file>" 

The <path/to/passphrase/file> shown previously is the absolute path to a text file containing the passphrase.

The dnf package manager will use the configured public key to verify the authenticity of the package feed.