 Posted by Rahul Mishra and Tom Watkins, Android Security &amp; Privacy Team [Cross-posted from the Android Developers Blog] In 2018, Google Play Protect made Android devices running Google Play some of the most secure smartphones available, scanning over 50 billion apps everyday for harmful behaviour. Android devices can genuinely improve people&#39;s lives through our accessibility features, Google Assistant, digital wellbeing, Family Link, and more — but we can only do this if they are safe and secure enough to earn users&#39; long term trust. This is Google Play Protect&#39;s charter and we&#39;re encouraged by this past year&#39;s advancements. Google Play Protect, a refresher Google Play Protect is the technology we use to ensure that any device shipping with the Google Play Store is secured against potentially harmful applications (PHA). It is made up of a giant backend scanning engine to aid our analysts in sourcing and vetting applications made available on the Play Store, and built-in protection that scans apps on users&#39; devices, immobilizing PHA and warning users. This technology protects over 2 billion devices in the Android ecosystem every day. What&#39;s new On by default We strongly believe that security should be a built-in feature of every device, not something a user needs to find and enable. When security features function at their best, most users do not need to be aware of them. To this end, we are pleased to announce that Google Play Protect is now enabled by default to secure all new devices, right out of the box. The user is notified that Google Play Protect is running, and has the option to turn it off whenever desired. New and rare apps Android is deployed in many diverse ways across many different users. We know that the ecosystem would not be as powerful and vibrant as it is today without an equally diverse array of apps to choose from. But installing new apps, especially from unknown sources, can carry risk. Last year we launched a new feature that notifies users when they are installing new or rare apps that are rarely installed in the ecosystem. In these scenarios, the feature shows a warning, giving users pause to consider whether they want to trust this app, and advising them to take additional care and check the source of installation. Once Google has fully analyzed the app and determined that it is not harmful, the notification will no longer display. In 2018, this warning showed around 100,000 times per day Context is everything: warning users on launch It&#39;s easy to misunderstand alerts when presented out of context. We&#39;re trained to click through notifications without reading them and get back to what we were doing as quickly as possible. We know that providing timely and context-sensitive alerts to users is critical for them to be of value. We recently enabled a security feature first introduced in Android Oreo which warns users when they are about to launch a potentially harmful app on their device. This new warning dialog provides in-context information about which app the user is about to launch, why we think it may be harmful and what might happen if they open the app. We also provide clear guidance on what to do next. These in-context dialogs ensure users are protected even if they accidentally missed an alert. Auto-disabling apps Google Play Protect has long been able to disable the most harmful categories of apps on users devices automatically, providing robust protection where we believe harm will be done. In 2018, we extended this coverage to apps installed from Play that were later found to have violated Google Play&#39;s policies, e.g. on privacy, deceptive behavior or content. These apps have been suspended and removed from the Google Play Store. This does not remove the app from user device, but it does notify the user and prevents them from opening the app accidentally. The notification gives the option to remove the app entirely. Keeping the Android ecosystem secure is no easy task, but we firmly believe that Google Play Protect is an important security layer that&#39;s used to protect users devices and their data while maintaining the freedom, diversity and openness that makes Android, well, Android. Acknowledgements: This post leveraged contributions from Meghan Kelly and William Luh. 