The installation process is completely secure. Libmng1 is installed through the official Ubuntu packaging system, from the official secured repositories. In case the application is already installed on your computer, a warning message will appear and no installation will occur.

During the installation process, your system might prompt you for your administrator password. Again, this is completely secure as it is your local system that asks for your administrator password and not Allmyapps. So, you can safely enter your password.