Personnel access control is a part of the access control system that validates the entry of authorized personnel into a controlled space such as an office building.
The system usually verifies your identity based on:
- What you have,
- What you know and,
- What you are.
What you have: Having a valid credential such as ID cards issued by govt or your company or school.
What you know: Knowing the personal identification number (PIN) such as your password that you use to access your computer or email or bank account or even some restricted office spaces.
What you are: Your bio-metrics (unique physical characteristics of an individual) such as fingerprints and iris details, which are collected for issuing your Aadhaar card or passport.
What you are or biometrics are used when you need high levels of security.