Patents by Inventor Yasushi Kuba

Yasushi Kuba has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • File encryption method and file cryptographic system
    Patent number: 5235641
    Abstract: In an information processing system having an upper rank apparatus and an external storage device which performs transmission and reception of data between the storage device and the upper rank apparatus, at least one of encryption and decryption of the data by use of an algorithm controlled by a desired data key is performed in the external storage device, while generation, encryption and decryption of the data key are performed on the upper rank apparatus side. By this configuration, the burden of the upper rank apparatus is largely reduced and the secrecy of data stored in the external storage device can be surely kept without spoiling the throughput of the whole system.
    Type: Grant
    Filed: March 12, 1991
    Date of Patent: August 10, 1993
    Assignee: Hitachi, Ltd.
    Inventors: Masafumi Nozawa, Akinobu Shimada, Toshifumi Nishimura, Katsuharu Kakuse, Tokuhiro Tsukiyama, Kiyoshi Yata, Yasuhiro Ishii, Kazuo Takaragi, Yasushi Kuba, Fujio Fujita