Hypatia is the worlds first FOSS malware scanner for Android. It is powered by ClamAV style signature databases.

• Near zero battery impact: you'll never notice any impact on battery at all
• Extremely fast: it can scan small files (1MB) in 20ms, and even large files (40MB) in 1000ms.
• Memory efficient: with the default databases enabled it uses under 120MB.
• Regular scan: allowing selection of /system, internal storage, external storage, and installed apps
• Realtime scanner: can detect malware in realtime on write/rename in internal storage
• Completely offline: Internet is only used to download signature databases, files will never ever leave your device
• Persistence: will automatically restart on boot/update
• Tiny codebase: coming in at under 1000 sloc, it can be audited by even someone with basic programming experience
• Minimal dependencies: the app only uses libraries when necessary
• Signature databases can be enabled/disabled at the users demand