Each pipe member has a plurality of slits located at intervals in the circumferential direction of the pipe member, extending in the axial direction of the pipe member, and extending through the pipe member in the radial direction of the pipe member. The method adopts a new technique of encrypting a password or any predefined secret information by a numeric function of itself, replacing the fixed public key of the conventional RSA encryption. The pressure resistance of the elements varies, allowing actuation signals to be manipulated to activate elements with different pressure resistance at different levels of the actuation signal.