It is doable, but your users need to do one extra step to view the contents.
A1 Cell will be visible to all, but not the others. Step: 1.Fill in the workbook and sheets as required 2.Ctrl+A select all the content \text set white as the font color, it makes it invisible 3. Review->Protect sheet, remove all the check boxes and set the password. 4. Repeat the steps for each sheet and separate passwords can be set on each one.
They can move the boxes and view, but not the selected cell hence the data remains hidden.
When the users unlock, they need to just select all and change the color back to automatic.