Abstract: A memory card insertion type electronic equipment reads authentication data from a memory card, decodes the read authentication data to a set of information by using a secret key, and compares the data read from an application program, which has been stored in the memory card, according to the address of the set of information with the data of the set of information in order to check the memory card for authenticity. There is also provided a memory card writing apparatus that encodes, by using a secret key, a set of information composed of an address generated at random and the data read from an application program, which is run on the memory card insertion type electronic equipment, according to the address, and writes the encoded set of information as the authentication data in the memory card.

Abstract: A motor-driven fuel pump including a motor section provided with a driving motor, and a pump section arranged below the motor section and provided with an impeller to be driven by the driving motor. A plurality of pressure compensation hollows are formed on opposite surfaces of a sealing portion of the impeller, and a plurality of communication holes are formed through the sealing portion for communicating the pressure compensation hollows. In another aspect, a plurality of pressure compensation passages are provided to be communicated to a higher pressure side of either a pump chamber defined around outer peripheral vanes of the impeller and a fuel well for receiving a fuel leaked along a sealing portion of the impeller.