"Meyerle is patenting a design for a modified cartridge that would be fired by a burst of high-frequency radio energy. But the energy would only ignite the charge if a solid-state switch within the cartridge had been activated. This would only happen if a password entered into the gun using a tiny keypad matched one stored in the cartridge."
'When they are sold, cartridges could be programmed with a password that matches the purchaser's gun. An owner could set the gun to request the password when it is reloaded, or to perform a biometric check before firing. The gun could also automatically lock itself after a pre-set period of time has passed since the password was entered."