I am not able to figure out a way to protect multiple cells at once. It seems that I need to select each cell individually, right click it, and then click the “Protect this cell with XLS Padlock”. Is there a way to protect 10s of cells at once without going manually over each one of the cells?
Unfortunately no, because we don’t recommend to protect all cells because this would slow down execution of Excel.
The goal is that if someone manages to remove the protection, protected cells will stop working and thus the workbook becomes useless. So basically, you should choose some cells to protect with XLS Padlock and use the hidden attribute for all other remaining ones.
There are known tricks to deprotect hidden cells through password cracking, but this requires VBA. If you block access to VBA editor with XLS Padlock, this should be OK.