Learn in the textbookUser Authentication (Knowledge-Based and Possession-Based)
DefinitionA user ID (利用者ID) is a name or number assigned so that a system can identify (識別) each user individually.
ExplanationEach person gets their own ID, and IDs are never shared. That way, the IDs left in the operation logs show afterward who did what and when.
AnalogyIt is like a student number at school: each number marks one student, and attendance is recorded by number.
Memory hookID is short for identification.