Nippon Telegraph and Telephone Corporation

Mitsubishi Materials Corporation

Dai Nippon Insatsu Kabushiki Kaisha

Ginya Ishiguro

Tatsuaki Okamoto

Atsushi Fujioka

Shoji Miyaguchi

Kazutaka Sakita

Toshiyasu Muta

Norio Yano

Takuo Takeshita

Yoshinari Ishii

Kouichi Ishiyama

Yasuaki Yoshioka

Hachiro Saito

Hirokazu Uekusa

An IC card has a card information memory area wherein there are written a master public key nA, card secret keys pU and qU, a card public key nU, a card identification number IDU, and a first master digital signature SA1 for information including the card identification number. An IC card terminal has terminal information memory area wherein there are written a master public key nA, terminal secret keys pT and qT, a terminal public key nT, a terminal identification number IDT, and a second master digital signature SA2 for information including the terminal identification number IDT. When inserted into the IC card terminal, the IC card sends thereto the data nU, IDU, and SA1. The IC card terminal verifies the digital signature SA1 by the master public key nA and, if it is valid, transmits the data nT, IDT and SA2 to the IC card. The IC card verifies the digital signature SA2 by the master public key nA and, if it is valid, transmits information corresponding to the current remainder value V to the IC card terminal. The IC card terminal makes a check to see if the received information corresponding to the remainder value V is appropriate, and if so, becomes enabled for providing a service.

Method and apparatus for settlement of accounts by IC cards

A magnetic recording powder for use as a material for magnetic recording media including magnetic tapes and magnetic cards, the powder having a high coercive force at room temperatures and a low Curie point, consists of at least one element selected from the group consisting of Y and rare-earth elements (R): 5-20 atomic %, B: 5-20 atomic %, Mn: 4-20 atomic %; and Fe and inevitable impurities: the balance. If required, the powder may further contain Al: 1-10 atomic %, and/or Cr: 1-10 atomic %. The powder has a mean particle size of 0.5-2 .mu.m and a mean crystal grain size of 0.1-0.4 .mu.m.

Magnetic recording powder having a high coercive force at room

A dual layered magnetic card with an apparatus for reading data therefrom and recording data thereon. The magnetic card includes (a) a card body, (b) a first magnetic layer disposed on the card body, the first magnetic layer including a first magnetic material, (c) a second magnetic layer disposed on the first magnetic layer, the second magnetic layer including a second magnetic material having Curie temperature lower than that of the first magnetic material and a coercive force at an ambient temperature higher than that of the first magnetic material. Also disclosed is an apparatus for reading data on the magnetic card, having a reader, post processor and data eraser, and an apparatus for reading and recording data having a recorder, reader, post processor and a data eraser.

Dual layered magnetic data card with reading and recording apparatus

In the subject magnetic card, first magnetic recording layer 2 is laid over substrate 1. First magnetic recording layer 2 has a coercive force that enables magnetic recording of data. Second magnetic recording layer 4, having a coercive force smaller than that of first magnetic recording layer 2, is laid over first magnetic recording layer 2, with shielding intermediate layer 3 interposed therebetween. Magnetic shielding layer 5 is provided as an uppermost magnetic layer.

Magnetic card

Growing community of inventors

Yokosuka, Japan

Ginya Ishiguro