PID

From The ReBoot Wiki

PID stands for Personal Identification. Every individual in the Net has a PID. They are stored in their icon. If a person gets ahold of anothers PID they can make that person do whatever they want. A persons PID must be on file for them to be registered online with a systems Principal Office.

Viruses must extract a persons PID in order to infect them. Superviruses are capable of infecting a person without direct access to their PID.