Patents by Inventor Takeshi Tanida

Takeshi Tanida 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).

  • Encrypted data recovery method using split storage key and system thereof
    Patent number: 6118874
    Abstract: When a secret is encrypted and stored, it is necessary to provide a countermeasure for the situation where a key is lost (key recovery system). In the present invention, a key recovery system for an enveloped data format in which a common key is used to encrypt a plaintext (secret) and a user's public key is used to encrypt the common key and attached to an encrypted text is provided. In the present invention, only the common key is decrypted to recover the secret without reconstruction of split secret keys kept in a plurality of key storage apparatuses.
    Type: Grant
    Filed: March 30, 1998
    Date of Patent: September 12, 2000
    Assignees: Hitachi, Ltd., Fujitsu Limited, Eiji Okamoto, Masahiro Mambo
    Inventors: Eiji Okamoto, Masahiro Mambo, Seiichi Domyo, Hiroyoshi Tsuchiya, Tooru Kawai, Kazuo Takaragi, Naoya Torii, Takeshi Tanida