It's possible to mount someone else's encrypted saves but there's currently no 'clean' way to do it.
Don't forget to regularly make backups of your saves and the savedata database, the ps4 deletes all your saves if the database gets corrupted while this mostly only happens when you actively mess with it, it's always better to be prepared some games require you to create your own save data with the appropriate name & size, fallout 4 is such a game.
the workaround method is obsolete since update 1.4 don't replace files in sce_sys directory, it is unnecessary and will probably corrupt your save you don't need to start a game to modify its saves, it's actually better not to have one open because some games like gow 4 may overwrite parts of a save while you're busy modifying it resulting in a corrupted save.
Click 'Search' & select the save you want to mount.Click 'Get Games' & select the game you want to use in the combobox.Click 'Setup' & select the user you want to use in the combobox.Enter the ip of your ps4 and click 'Connect'.net framework 2.0 executables (even windows 98 can run this) To make sure you're using a recent ps4debug version, bin of the latest ps4debug (as of 11/14) is included in the download.Make decrypted copies of any save (as long as it's encrypted with keys 5.05).This program allows you to mount save data with RW permission and a lot more shit, just read this damn thing You can