If you push the image for the first time, You will be asked to enter the root key passphrase. This will be needed every time you push a new image while the DOCKER_CONTENT_TRUST flag is set.
The root key is generated at: /root/.docker/trust/private/root_keys
You will also be asked to enter a new passphrase for the image. This is generated at /root/.docker/trust/private/tuf_keys/[registry name] /[imagepath].
If you are using a self-signed cert, make sure to copy the CA cert into /etc/docker/certs.d/10.117.169.182 and $HOME/.docker/tls/10.117.169.182:4443/. When an image is signed, it is indicated in the Web UI.
A signed image will have a checkbox next to it, otherwise an X is displayed instead.
If you want to remove a tag signature from harbor, you can use ‘notary remove’ command: