This disclosure describes techniques that may prevent cryptographic devices, including both encryption devices and decryption devices, from producing a power signature that can be used by attackers to deconstruct a cryptographic algorithm and extract a cryptographic key. The pair of complementary plates together forms a tubular flow passage and one or more tubular sections. A proximal end of the barrel is received at least partially through the axial bore, and the barrel nut releasably engages a front end of the receiver. The second convertor is connected to the controller for receiving the first voltage, converting the first voltage into a third voltage to power an operating unit of the electronic device, and converting the first voltage into a fourth voltage to power the controller when receiving the start signal. In this manner, whenever the UE enters any of the venues, the UE is automatically authenticated when it comes within range of any AP within any of the venues.