This article can be taken from OpenSource.com titled “Manage Linux users’ home directories with systemd-homed“
The systemd-homed service supports user account portability independent of the underlying computer system. A practical example is to carry around your home directory on a USB thumb drive and plug it into any system which would automatically recognize and mount it. According to Lennart Poettering, lead developer of systemd, access to a user’s home directory should not be allowed to anyone unless the user is logged in. The systemd-homed service is designed to enhance security, especially for mobile devices such as laptops. It also seems like a tool that might be useful with containers.
This objective can only be achieved if the home directory contains all user metadata. The ~/.identity file stores user account information, which is only accessible to systemd-homed when the password is entered. This file holds all of the account metadata, including everything Linux needs to know about you, so that the home directory is portable to any Linux host that uses systemd-homed. This approach prevents having an account with a stored password on every system you might need to use.
The home directory can also be encrypted using your password. Under systemd-homed, your home directory stores your password with all of your user metadata. Your encrypted password is not stored anywhere else thus cannot be accessed by anyone. Although the methods used to encrypt and store passwords for modern Linux systems are considered to be unbreakable, the best safeguard is to prevent them from being accessed in the first place. Assumptions about the invulnerability of their security have led many to ruin.
This service is primarily intended for use with portable devices such as laptops. Poettering states, “Homed is intended primarily for client machines, i.e., laptops and thus machines you typically ssh from a lot more than ssh to, if you follow what I mean.” It is not intended for use on servers or workstations that are tethered to a single location by cables or locked into a server room.
The systemd-homed service is enabled by default on new installations—at least for Fedora, which is the distro that I use. This configuration is by design, and I don’t expect that to change. User accounts are not affected or altered in any way on systems with existing filesystems, upgrades or reinstallations that keep the existing partitions, and logical volumes.Manage Linux users’ home directories with systemd-homed (OpenSource.com)
For more Read-Up, do take a look at “Manage Linux users’ home directories with systemd-homed“