They exist! One maker (who's product didn't last on the market for very long) back in the 70s or 80s, actually had this sort of obfuscation as a feature on the

They exist! One maker (who's product didn't last on the market for very long) back in the 70s or 80s, actually had this sort of obfuscation as a feature on the key. Basically, the key was a series of connected sections with small differences between them, they would slide into the lock from the middle of a spring-loaded sheath and then follow an odd path inside the lock, so neither observation of the keyway, the sheathed key, or even likely the unsheathed key, would give you a clear picture of how to reconstruct the interaction between the sections of the key, or where in the lock they interacted. Sadly I have no patent reference for the lock, only a description in an old newspaper that ran a story on the creator.