T4 Core Rules, p.66:
Imperial ID
Also known as the "Universal ID," or more often just the "Universal," this contains authenticated identity information about a person, such as fingerprint, name, date of birth, holographic photo, and so on. This info is encrypted on the card, the encryption being updated every day or so based on an internal clock and computer.
Normally, most transactions just go through a person's comm, which has links to the necessary databases—bank account, passport control, etc. In cases where a more secure ID is required, however, the Office of Imperial Records also is queried, which in turn queries the person's Universal, decrypts the information there based on the current day-and-date code, and can thus provide backup identification.
A Universal is free on most Imperial worlds, but it can be a troublesome process to replace one that has been lost or stolen.
THE VALUE OF ID
In the Imperium, ID is everything. Indeed, there are urban legends and tri-d dramas about people getting lost in the system. After having their ID scrambled somehow, their car would not start, their house locked them out, and they could not even place a comm call to Imperial Services to get the situation fixed.
There are now safeguards built into the system so that in the event this happens, a "safety net" will catch a person in the form of toll-free emergency lines, support services, etc. It can still be a terrible pain, but it happens to only about one person per million lifetimes.
Still, no one wants to be that one person.