Change the permission of multiple files using the GUI I am looking for a way to change the permission of multiple files using the GUI.
I tried to select all the files and hit show info in the right click context menu, but this opens multiple dialogs where I have to enter my admin password and then change the permission. 

Is there an easier way to accomplish this task?
You can use Finder to change multiple files permissions. Command+Option+i will open the Multiple Item Info panel that should set the permissions for all files that have been selected (it also gives you total file size, and lets set label colors too).

Otherwise you can select the folder the files you want to change are in, and use the regular get info window to set permissions on all containing files.