Best Free Security and Privacy for Android
Best Free Anti-malware for Android
avast! Mobile Security & Antivirus (8.5 MB), a feature-rich security app includes not only a virus scanner to scan all your installed apps and SD card content against viruses, but also other useful tools such as privacy advisor, app manager, web shield, SMS and call filter and anti-theft. It also adds a firewall which works only on rooted phones. (Review)
Lookout Antivirus & Security (7.7 MB), protect your device and data easily by blocking viruses, spyware or other malware and scanning every app you installed with automatic antivirus updates, backup your contacts to the web or restore data to an existing phone, find your missing phone and more. Privacy Advisor is only available to the paid-for premium version. (Review)
TrustGo Antivirus & Mobile Security (4.9 MB), a simple yet powerful security app with awesome anti-malware capabilities, secure web browsing and a secure app advisor. This app has low impact on your device's resources. (Review)
CM Security - FREE Antivirus (9.7 MB), tap on a big Scan button to start scanning the installed apps and file system to detect any viruses, trojan, vulnerability, adware and spyware that could exist on your device. It's lightweight and its scanning process is pretty fast. (Review)
VirusTotal for Android (492 KB) helps get your system and user apps in your device scanned by more than 40 antivirus vendors and flag any malicious apps. Tap a flagged app and you can view its detailed scan results from the vendors.
Best Free Apps Protection for Android
APP Lock (638 KB), protect your installed apps with a number or pattern lock using this handy app, with other useful features such as locking the install and uninstall functions, incoming calls, settings, hiding the APP Lock icon and short exits without the need to unlock again.
Perfect App Protector - FREE (3.7 MB), lock your selected apps with a password or pattern, reduce screen brightness and control screen rotations on the apps you chose, plus stealth mode and other useful features.
Application Protection (328 KB), easily help protect applications and data on your device with a passcode to prevent unauthorized usage. Upon first running, press "?" to get the original code, add apps to the list then set your own unlock code.
Best Free Device Tracker for Android
Wheres My Droid (651 KB), finding your misplaced phone is made easy—use another phone to text "Where's my droid" to make your lost phone ring even if it's on silent mode, or text "GPS my droid" to know its whereabouts. Simple as that.
Prey Anti-Theft (3.0 MB), "Once the device has been instructed to go into missing mode, the app springs into action and does whatever you've told it to do. You can either trace your device, lock it or delete the files on it." (Review)
Best Free Password Manager for Android
KeePassDroid (1.3 MB), too many passwords to remember? This app helps manage passwords easily—just remember one single master password or select the key file to unlock them. A good implementation of desktop software KeePass Password Safe or even KeePassX.
Keeper Password & Data Vault (4.6 MB), a simplistic app that saves all your passwords onto your mobile phone with a master password. Features include optional self-destructs after entering five wrong passwords but cloud bakcup is only available on the paid version.
Best Free Private Gallery for Android
Gallery Lock (4.4 MB), manage your private photos and videos by hiding them into folders accessible only with your password or pattern lock. The app supports slideshow and other options, but stealth mode and backup are available only on the paid version.