Patents by Inventor Yoshimichi Tanizawa

Yoshimichi Tanizawa 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).

  • Publication number: 20160285629
    Abstract: According to an embodiment, a quantum key distribution device includes a sharer, a key distillation processor, a first manager, and a second manager. The sharer is configured to share a photon string with the another quantum key distribution device using quantum key distribution via a quantum distribution channel, and obtain a photon bit string corresponding to the photon string. The key distillation processor is configured to generate a link key from the photon bit string. The first manager is configured to store the link key as a link transmission key. The second manager is configured to store, in a storage, a first application key from an application key to be used in cryptographic data communication, encrypt a second application key from the application key, using the link transmission key, and send the encrypted second application key to another quantum key distribution device via a classical communication channel.
    Type: Application
    Filed: October 22, 2015
    Publication date: September 29, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Yoshimichi TANIZAWA
  • Patent number: 9455827
    Abstract: According to an embodiment, a communication apparatus includes a cryptographic key storage, a transmitter, a receiver, and a sharing controller. The cryptographic key storage stores therein one or more cryptographic keys shared with an external device. The transmitter transmits specifying information that specifies at least one of the cryptographic keys to the external device. The receiver receives determination information that indicates a result of determination, which is made by the external device based on the specifying information, on whether the shared cryptographic key is consistent between the apparatus and the external device. When receiving the determination information indicating that the shared cryptographic key is inconsistent between the apparatus and the external device, the sharing controller deletes the cryptographic key specified by the specifying information from the cryptographic key storage.
    Type: Grant
    Filed: July 31, 2014
    Date of Patent: September 27, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshimichi Tanizawa, Hideaki Sato, Ririka Takahashi, Alex Dixon
  • Publication number: 20160277183
    Abstract: According to an embodiment, a quantum-key distribution apparatus includes a quantum-key sharer, a shifter, a corrector, a privacy amplifier, and an estimator. The quantum-key sharer performs photon sharing processing and acquires a photon bit string. The shifter generates a shared bit string by performing shifting processing. The corrector generates a corrected bit string by correcting errors in the shared bit string by performing error correction processing. The privacy amplifier generates an encryption key by performing privacy amplification processing that compresses the corrected bit string. The estimator estimates an encryption-key generation rate based on an output value and a given value at execution phases of respective pieces of processing of the photon sharing processing, the shifting processing, the error correction processing, and the privacy amplification processing.
    Type: Application
    Filed: January 20, 2016
    Publication date: September 22, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Akira MURAKAMI, Yoshimichi TANIZAWA
  • Patent number: 9450929
    Abstract: According to an embodiment, a communication device is connected to a plurality of external devices which share key information with each other. The communication device includes a detector and an instructing unit. The detector is configured to, from among the external devices, detect an external device that has been subject to attack. The instructing unit is configured to issue an instruction to stop using key information which is shared with the detected external device.
    Type: Grant
    Filed: November 18, 2013
    Date of Patent: September 20, 2016
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshimichi Tanizawa, Hideaki Sato, Ririka Takahashi
  • Publication number: 20160269177
    Abstract: According to a communication device includes a sharing processing unit, a storage, and a controller. The sharing processing unit shares an encryption key with one or more external devices. The storage stores therein the encryption key. The controller compares a current amount representing an amount of the stored encryption key with a specified reference amount and performs control to continue or stop sharing processing, which is performed by the sharing processing unit, for sharing the encryption key on the basis of a comparison result.
    Type: Application
    Filed: October 2, 2015
    Publication date: September 15, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Yoshimichi Tanizawa
  • Publication number: 20160218868
    Abstract: According to an embodiment, a quantum key distribution device includes a quantum key distributor, a sifter, a corrector, an identifier, a classifier, a calculator, and a privacy amplifier. The quantum key distributor obtains a photon string from a photon string of two or more intensities of light pulses. The sifter obtains pulse information indicating the light pulse to which each bit of a shared bit string corresponds. The corrector corrects an error included in the shared bit string and generates a post-correction bit string. The identifier generates error position information. The classifier classifies each bit of the post-correction bit string. The calculator calculates the error rate for each light pulse and each base using the error position information. The privacy amplifier generates a cryptographic key from the post-correction bit string on the basis of the error rate.
    Type: Application
    Filed: September 21, 2015
    Publication date: July 28, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Ririka TAKAHASHI, Yoshimichi TANIZAWA
  • Patent number: 9356780
    Abstract: A communication device assigns a key taking the degree of priority of applications into account in a case where a key generation/sharing system in which a plurality of applications are connected to a node is not able to realize key assignment that satisfies the key rates requested by the plurality of applications. For example, the device realizes a method of assigning an application key that takes the degree of priority into account according to which control is performed in such a way that the key rate requested by an important application is preferentially satisfied.
    Type: Grant
    Filed: February 25, 2014
    Date of Patent: May 31, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshimichi Tanizawa, Hideaki Sato, Ririka Takahashi, Shinichi Kawamura, Shinya Murai
  • Patent number: 9350542
    Abstract: According to an embodiment, a quantum key distribution (QKD) device includes a sharing unit, a correcting unit, a deciding unit, a calculator, and a privacy amplifier. The sharing unit is configured to generate a shared bit string through quantum key distribution with each other QKD device connected via quantum communication channels. The correcting unit is configured to generate a corrected bit string through an error correction process on the shared bit string. The deciding unit is configured to calculate an error rate in the corresponding quantum communication channel with respect to each other QKD device, and decide on a combined error rate from error rates calculated. The calculator is configured to calculate, based on the combined error rate, a length of an encryption key to be shared. The privacy amplifier is configured to generate the encryption key having the calculated length of the encryption key from the corrected bit string.
    Type: Grant
    Filed: January 26, 2015
    Date of Patent: May 24, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ririka Takahashi, Yoshimichi Tanizawa
  • Publication number: 20160142203
    Abstract: According to an embodiment, a quantum key distribution device includes first and second operation units. The first operation unit is configured to perform a first operation as a key distillation operation. The first operation unit includes a hardware circuit for performing a part of the first operation. The key distillation operation includes a sifting operation for a photon bit string generated through quantum key distribution with another quantum key distribution device via a quantum communication channel. The second operation unit is configured to perform a second operation as a key distillation operation other than the first operation. The second operation unit includes a circuit for a part of the second operation. The first operation unit stores intermediate data generated by the first operation. The second operation unit generates, by the second operation, a cryptographic key being the same as for the another quantum key distribution device from the intermediate data.
    Type: Application
    Filed: September 30, 2015
    Publication date: May 19, 2016
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yoshimichi TANIZAWA, Hideaki SATO, Kazuaki DOI, Ririka TAKAHASHI, Akira MURAKAMI
  • Patent number: 9313184
    Abstract: According to an embodiment, a communication apparatus includes a sharing processing unit, an extension unit, and a communication unit. The sharing processing unit shares a first cryptographic key with an external apparatus connected via a link, and further generates a second cryptographic key and shares the second cryptographic key with the external apparatus through secret communication using the first cryptographic key. The extension unit generates an extended key by extending a length of the second cryptographic key. The communication unit transmits the extended key to a first application which communicates with a second application to which the external apparatus provides the second cryptographic key.
    Type: Grant
    Filed: January 22, 2014
    Date of Patent: April 12, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshimichi Tanizawa, Hideaki Sato, Shinichi Kawamura
  • Patent number: 9306734
    Abstract: According to an embodiment, a communication device is connected to a key generating device which generates an encryption key. The communication device includes a querying unit, an encryption processor, and a selecting unit. The querying unit is configured to send a query to the key generating device about capability information which indicates capability of the key generating device to generate the encryption key. The encryption processor is configured to implement a plurality of encryption functions. The selecting unit is configured to select, from among the plurality of encryption functions, an encryption function according to the capability information. The encryption processor implements the encryption function thus selected.
    Type: Grant
    Filed: March 12, 2013
    Date of Patent: April 5, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshimichi Tanizawa, Shinichi Baba
  • Patent number: 9294269
    Abstract: In general, according to one embodiment, a communication apparatus includes an obtaining unit, generation unit, and communication unit. The obtaining unit obtains a master key from a first communication apparatus. The generation unit generates an individual key using the master key. The communication unit communicates with a second communication apparatus using the individual key.
    Type: Grant
    Filed: November 20, 2013
    Date of Patent: March 22, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yasuyuki Tanaka, Mitsuru Kanada, Yoshimichi Tanizawa
  • Patent number: 9240882
    Abstract: According to an embodiment, a key generating device connected to an external device includes a generating unit configured to generate an encryption key; a first communicating unit configured to transmit and receive the encryption key to and from the external device; a storage unit configured to stores therein state information indicating a communication state with respect to an application using the encryption key; and a controller configured to make a control of changing a frequency at which the generating unit generates the encryption key or a frequency at which the first communicating unit transmits and receives the encryption key according to the state information.
    Type: Grant
    Filed: December 14, 2012
    Date of Patent: January 19, 2016
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshimichi Tanizawa, Shinichi Baba
  • Patent number: 9197608
    Abstract: According to one embodiment, a communication method including acquiring an application key from a key-sharing network, determining a key use of the application key, and performing encryption communication by using the application key according to the determined key use.
    Type: Grant
    Filed: August 21, 2013
    Date of Patent: November 24, 2015
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshimichi Tanizawa, Shinichi Baba
  • Patent number: 9191406
    Abstract: A storage unit of a relaying apparatus stores first identification information that identifies an SIP terminal and second identification that identifies other SIP terminal which is forecast as a transfer destination of a message. A transmitting-and-receiving unit receives from the SIP terminal a request message that is received before a transfer message to be transferred to other SIP terminal and that includes a processing request concerning communications and the first identification information. An obtaining unit obtains from a storage unit the second identification information corresponding to the first identification information included in the received request message. A connection establishing unit establishes communications between the other SIP terminal of the obtained second identification information and the relaying apparatus.
    Type: Grant
    Filed: November 14, 2007
    Date of Patent: November 17, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshimichi Tanizawa, Naoki Esaka, Tsutomu Shibata
  • Publication number: 20150270963
    Abstract: According to an embodiment, a communication device includes a first manager, and a second manager, a first communication unit, a determination unit, a controller, and a second communication unit. The first manager shares a first cryptographic key with a first external device connected via a link. The second manager shares a second cryptographic key to be provided to an application, with the first external device and with a second external device connected via links. The first communication unit transmits the second cryptographic key to the first external device. The determination unit determines whether a device with which the second cryptographic key is to be shared is the first external device. If it is affirmative, the controller controls the second manager to share, as the second cryptographic key, a cryptographic key obtained by converting the first cryptographic key. The second communication unit provides the application with the second cryptographic key.
    Type: Application
    Filed: March 12, 2015
    Publication date: September 24, 2015
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Yoshimichi TANIZAWA
  • Publication number: 20150271147
    Abstract: According to an embodiment, a communication system includes a plurality of communication apparatuses. Each of the communication apparatuses includes a key generator and a synchronization processor. The key generator generates shared keys shared with another communication apparatus. The synchronization processor synchronizes at least one of order of using the generated shared keys and roles played when the generated shared keys are used, with another communication apparatus based on a rule determined in advance.
    Type: Application
    Filed: March 9, 2015
    Publication date: September 24, 2015
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yoshimichi TANIZAWA, Hideaki SATO
  • Publication number: 20150270959
    Abstract: According to an embodiment, a communication device is connected to another communication device through an optical communication path to generate an identical cryptographic key shared among the communication devices. The communication device includes a key sharing unit, a key distilling unit, a measuring unit, and a varying unit. The key sharing unit is configured to generate a shared bit string through quantum key distribution with the another communication device. The key distilling unit is configured to generate the cryptographic key from the shared bit string by a key distillation process. The measuring unit is configured to measure an error rate occurring in a photon string transmitted and received via a photon communication channel. The varying unit is configured to vary, based on the error rate, a communication function by applying a limitation on the optical data communication of an optical data communication channel or by releasing the limitation.
    Type: Application
    Filed: March 11, 2015
    Publication date: September 24, 2015
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yoshimichi Tanizawa, Alex Dixon
  • Publication number: 20150236852
    Abstract: According to an embodiment, a quantum key distribution device includes a key sharing unit, a correcting unit, a compressor, and a controller. The key sharing unit is configured to generate a shared bit string by using quantum key distribution performed with another quantum key distribution device via a quantum communication channel. The correcting unit is configured to generate a corrected bit string through an error correction process with respect to the shared bit string. The compressor is configured to generate an encryption key through a key compression process with respect to the corrected bit string. The controller is configured to perform a restraining operation in which the total number of bits of encryption keys generated per unit time by the compressor is smaller than the total number of bits of the encryption keys generated per unit time by the compressor in the case of not performing the restraining operation.
    Type: Application
    Filed: February 13, 2015
    Publication date: August 20, 2015
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Yoshimichi TANIZAWA
  • Patent number: 9106406
    Abstract: According to an embodiment, a communication apparatus includes a key storage unit configured to store therein a cryptographic key; a receiving unit configured to receive a message; an analyzing unit configured to analyze whether the message includes an access request for the cryptographic key; a generating unit configured to, when the message includes the access request, generate request information used to request an access to the cryptographic key requested by the access request; and an access controller configured to control the access to the cryptographic key based on the request information.
    Type: Grant
    Filed: August 28, 2012
    Date of Patent: August 11, 2015
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Shinichi Baba, Yoshimichi Tanizawa, Hideaki Sato