Android is a very flexible mobile operating system that can fulfill all these mobile device security challenges if you select the right security applications from Google Play Store. As Mobile Device Security is comprised of security of different features, such as: Data privacy and security features. RedPhone is a free secure call app that provides end-to-end encryption for your private calls, securing your phone conversations in a way that nobody can listen in. Red phone uses your standard phone number to make and receive phone calls, so there is no need for any other identifier.
Source: https://thehackernews.com/2015/04/android-privacy-security-apps.html