The strongest access control is multi-factor authentication.
That means combining at least two of these:
- Something you have (card, phone)
- Something you know (PIN)
- Something you are (fingerprint, face scan)
For example: a keycard + PIN, or fingerprint + mobile credential.
This is considered the strongest because even if one factor is stolen or copied, the system still won’t allow access. It dramatically reduces the risk of unauthorized entry compared to single-method systems.