NUME BETA application is designed to encrypt voice on Android OS mobile phones. It is available free of charge on Google Play (link: https://forums.androidcentral.com/e...bS5hbmNvcnQuY3J5cHRvcGhvbmUiXQ&token=fvsU2Ra6..). When you download it on your mobile phone enter your mobile phone number according to the international standard (up to 25 digits). Good luck!