First off, no you can't.
There is no magic box that no one can break into or tamper with, telling yourself that is just a delusion.
That's like saying you have a house no one can break into. It's just short-sighted.
People make this same argument for physical locks vs digital locks on cars and houses.
If you actually learned anything about encryption technologies, you would know they're more secure than 90% of the physical security measures we use as humans...
Even if they were not, that's only a reason to improve upon them, not pretend we live in the stone-age out of fear that we'll fail.