autounlock

Autounlock refers to mechanisms that permit automatic unlocking of a device or application when a separate authenticated credential is present, reducing the need for manual login each time. It relies on a trusted relationship between the target system and a companion device, user credential, or cryptographic key. Implementations typically use proximity sensing, devices paired via Bluetooth or NFC, or a secure element that proves the user’s identity without prompting for a password.

Common implementations include:

- macOS Auto Unlock: In macOS, users can unlock a Mac automatically when nearby with an authenticated Apple Watch; requires an iCloud account, two-factor authentication, and Bluetooth enabled. The watch must be unlocked and on the user’s wrist.

- Android Smart Lock: Android devices can stay unlocked in trusted conditions, such as when connected to a trusted Bluetooth device, in a trusted location, or when facial recognition and voice match; balances convenience with security by requiring re-authentication in certain scenarios.

- Enterprise or hardware tokens: Some organizations use proximity-based or time-based unlock with hardware security keys or smart cards, enabling automatic access to services when the user is at a known workstation or connected to a VPN.

Security and limitations: Autounlock can improve usability but expands the potential attack surface if the trusted credential is lost, stolen, or compromised. Best practices include limiting unlocked contexts, enabling re-authentication for sensitive actions, revoking access promptly, and combining with additional factors when appropriate.