Android security issues make the news just about every day, from malicious apps appearing in the Google Play app store to mobile malware spreading via SMS. While Android is a flexible and easy-to-use mobile operating system available on a wide variety of great devices, the mobile threat landscape has now made it essential for users to install additional security options.
Keep in mind that the most basic security precautions, like password-protecting your device and setting it to auto-lock after a specified period of time, don't require an app – both of those features can be accessed within Settings > Location & Security. And most Android devices offer a variety of unlock options, including a numeric PIN, a password or a graphical pattern.
But don't stop there. From anti-virus apps (crucial at this point) to enhanced password protection, it's worth taking a look at several more advanced options. The vast number of security apps available for the platform makes it impossible to cover them all here, but what follows should give you a good sense of the options available when seeking further protection for your Android device and the data that resides on it.
Lookout Security & Antivirus (free) blocks malware, spyware and Trojans, with user-schedulable daily or weekly anti-virus scans as well as automatic scanning of new apps and files when they're downloaded. Additional features include the ability to locate a lost or stolen phone on a Google map and activate a loud alarm to help find the device, and the ability to back up and restore the user's contact list. Lookout Premium ($29.99/year or $2.99/month) adds phishing protection, privacy protection, remote lock and data wipe functionality, and the ability to back up and restore the user's photos and call history in addition to contacts. Lookout

Avast avast! Mobile Security (free) provides a wide range of functionality, including a Virus Scanner that enables on-demand scans of all apps installed on the device and SD card, along with scans of any newly installed apps upon initial execution. The Privacy Advisor displays the access rights and intents of installed apps, identifying any potential privacy risks. The Application Manager shows a list of running apps along with their size, CPU load, used memory, and number of threads and services, and enables the user to stop or uninstall any app as needed. The Web Shield scans every URL loaded on the device, and warns the user if a malware-infected site is being accessed. The SMS and Call Filter can be used to filter calls and/or messages from the user's contact lists. The Firewall, usable only on rooted phones, can disable an app's Internet access when on Wi-Fi, 3G, and roaming networks. Finally, Anti-Theft features include the ability to disguise the app with a custom name, to hide the app icon in the app tray, and more. If a device is lost or stolen, it can be remotely prompted to sound a siren, lock, display a custom message, be located on a map, be wiped remotely, and more.

AVG Antivirus Free scans all apps, settings, files, and media in real time; guards against phishing attacks; blocks access to malicious Web sites; kills tasks that slow down or freeze the device; and allows users to locate a lost or stolen phone via Google Maps, lock the device remotely, display a custom lock