Key Storage vs. Usage.

Generating and storing cryptographic keys is largely solved. Hardware wallets, secure enclaves, HSMs, and cloud services all do this well.

Where systems struggle is key use. Deciding when a key can be used, by whom, from where, and under what conditions is where complexity arises. That logic quickly spills outside cryptography and into permissions, identity, workflows, and operational controls.

Having logical definitions for access only takes you so far. Both the system and the user need to understand the way the system is structured to take full advantage of it.