Unless I've misunderstood you, you're suggesting that these abstract concepts actually have representation in metaphysical reality. That's the definition of Platonism. Time, space, these are in the realm of physics. A key is just a number, and numbers don't exist in the physical realm. They exist in the mind only.

This is good. We want it this way. Bitcoin is better when people know that it is purely information and has no other special status.

As for a key, a key is not authority. If someone steals a key, they to not suddenly become authorized to open the lock. Is a burgler free of guilt if they used a key to enter your home?