Google has recapped 2015 with their annual Android Security report. When it comes to Android security the main security concerns are keeping devices updates and on current versions of Android and preventing malicious apps from being installed.
Apps with the malicious habits of collecting data, spyware, or a hostile downloader were all significantly decreased. Over 6 billion applications and 400 million devices were checked each day to see if they were malicious or potentially harmful. Android 6.0 Marshmallow brought a lot of new security features including full disk encryption required, granular app permissions, verified boot, Android security patch level, fingerprint scanners, and others. Google also added Android the Google Vulnerability Rewards Program (bug bounty) last June and have paid over $200,000 for Android findings.