I thought about a way to make a safe or lockbox with a solenoid operated lock. 10 SPST push button switches in series with a battery and proper solenoid. Three or four n/o switches and the rest n/c. All n/o switches would have to be made and none of the n/c switches. All the switches of course would need to look identical. If any one of the n/c switches was made it would open the circuit and the solenoid would not be energized.