Sentry

Sentry is a small Android application for enforcing selected security policies on a device. It is intended for users who need controls over password failures, USB data access, safe boot, and security-related notifications. Its focus places it in the Security & Privacy category rather than general device administration.

Sentry can set a maximum number of failed password attempts. It can disable USB data connections on Android 12 when the device uses USB HAL 1.3 and Sentry has Device Owner status. On Android 7, it can disable safe boot when it has Device Owner status. The app can notify the user about failed password attempts and about an application that receives Internet permission after an update despite not having that permission before.

The DEVICE_ADMIN permission supports limiting failed password attempts, while DEVICE_OWNER supports disabling USB data connections. NOTIFICATION_LISTENER is used to receive lock and package events, and QUERY_ALL_PACKAGES is used to receive all package events. Sentry may not work in safe mode, which is relevant when relying on its controls or notifications.

Sentry is free open-source software released under GPL-3. MirrorNest hosts a direct mirror of the official build on its own storage and scans it for malware before publishing. This distribution model gives Android users access to the official build through a download catalog while preserving its open-source and Security & Privacy classification.