Patents by Inventor Masahiko Takenaka

Masahiko Takenaka 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: 20070192609
    Abstract: An electronic image data verification program disclosed herein is capable of detecting presence or absence of a change, specifying a changed portion (the position of a change) if present, and making the presence or absence and the changed portion provable to third parties, by generating partial signature information separately from electronic image information to be registered, by dividing and maintaining the partial signature information, and by clearly separating functions/roles of the electronic image information (original information) and the partial signature information (verification information).
    Type: Application
    Filed: January 20, 2006
    Publication date: August 16, 2007
    Applicant: FUJITSU LIMITED
    Inventors: Takashi Yoshioka, Masahiko Takenaka
  • Publication number: 20070177721
    Abstract: An encryption device (10) for performing elliptic encryption processing with a private key, includes: randomizing means (16) for setting, into an initial elliptic point V0, an elliptic point R on an elliptic curve that is generated in accordance with a random value; operation means (20) for performing a first operation of summing the initial elliptic point V0 and a scalar multiple of a particular input elliptic point A on the elliptic curve, V1=V0+dA, in accordance with a bit sequence of a particular scalar value d for the elliptic encryption processing; de-randomizing means (22) for performing a second operation of subtracting the initial elliptic point V0 from the sum V1 determined by the first operation, V=V1?V0; and means (24) for providing, as an output, the elliptic point V determined by the de-randomization unit.
    Type: Application
    Filed: November 15, 2005
    Publication date: August 2, 2007
    Applicant: FUJITSU LIMITED
    Inventors: Kouichi Itoh, Tetsuya Izu, Masahiko Takenaka, Naoya Torii
  • Publication number: 20070168672
    Abstract: Disclosed is a digital document management program capable of achieving a third-party certification of document information with reduced amount of meta data. At the registration time of new document information, the digital document management program manages a digital signature created in association with document information. At the correction time of the document information, the program acquires partial identification information related to a corrected part of the document information before correction, creates a digital signature to be appended to the corrected document information, and manages the digital signature and partial identification information related to the corrected part of the document information in association with the corrected document information.
    Type: Application
    Filed: August 30, 2006
    Publication date: July 19, 2007
    Applicant: Fujitsu Limited
    Inventors: Tetsuya Izu, Masahiko Takenaka, Takashi Yoshioka
  • Publication number: 20070168671
    Abstract: Disclosed is a digital document management program capable of achieving a third-party certification of document information with reduced amount of meta data. At the registration time of new document information, the digital document management program manages a digital signature created in association with document information. At the correction time of the document information, the program acquires partial identification information related to a corrected part of the document information before correction, creates a digital signature to be appended to the corrected document information, and manages the digital signature and partial identification information related to the corrected part of the document information in association with the corrected document information.
    Type: Application
    Filed: April 14, 2006
    Publication date: July 19, 2007
    Applicant: Fujitsu Limited
    Inventors: Masahiko Takenaka, Tetsuya Izu, Takashi Yoshioka
  • Publication number: 20070050713
    Abstract: Disclosed is a digital document management system and the like capable of guaranteeing that a partial correction has been made according to a proper procedure and achieving a third-party certification of the validity of the guarantee. A digital document management system that manages document information created in a digital form, comprising: a partial identification information generation section 51 that generates partial identification information that represents, in an identifiable manner, respective parts of the document information; a partial correction information generation section 52 that generates partial correction information which is information related to a correction history of a corrected part in the case where any correction has been required for the document information; and an original document information management section 40 that manages the document information, partial identification information, partial correction information, and prescribed policy information in an associated manner.
    Type: Application
    Filed: October 18, 2006
    Publication date: March 1, 2007
    Inventors: Takashi Yoshioka, Masahiko Takenaka
  • Publication number: 20070016942
    Abstract: An encrypted ID takes as its initial value a tag ID that constitutes an original ID of a wireless tag, and is encrypted using an encryption key each time an ID inquiry is received from a reader/writer. Another encrypted ID also takes the tag ID as its initial value, and is encrypted using an encryption key each time an ID inquiry is received. The wireless tag gives confidential variability to the ID by transmitting a combination of the encrypted ID and the another encrypted ID in reply. The reader/writer can obtain the original ID merely by decoding the two encrypted values until they match, and the decoding load does not increase even if the number of wireless tags that are reading targets increases.
    Type: Application
    Filed: February 15, 2006
    Publication date: January 18, 2007
    Applicants: FUJITSU LIMITED, FUJITSU FRONTECH LIMITED
    Inventors: Atsushi Sakai, Koken Yamamoto, Masahiko Takenaka
  • Publication number: 20060276206
    Abstract: An information access system comprises a reader/writer for continually transmitting an ID request signal at a first frequency and being continuously ready to receive an RF signal at a second frequency, and an active contactless information storage device having a receiver for sensing a carrier of an RF signal at the first frequency, and a transmitter for transmitting a response signal at the second frequency when the ID request signal is received. When the receiver senses a carrier of an RF signal at the first frequency in a particular predetermined period, the receiver receives further the ID request signal, and, in response to the ID request signal, the transmitter transmits a response signal at the second frequency carrying an ID of the storage device stored. In the carrier sensing, the controller causes the receiver to be in an active state and the transmitter to be in an inactive state in the predetermined periods.
    Type: Application
    Filed: October 12, 2005
    Publication date: December 7, 2006
    Applicant: FUJITSU LIMITED
    Inventors: Shinichi Shiotsu, Isamu Yamada, Satoshi Inano, Kouichi Yasaki, Akira Itasaki, Atsushi Sakai, Masahiko Takenaka, Takanao Ochiai
  • Publication number: 20060235921
    Abstract: A method for calculating a conversion parameter of the Montgomery modular multiplication to improve the efficiency of software installation, comprising a first step for calculating H0=2v×R (mod n) (where v is an integer, v?1, and (m×k)/v is an integer), a second step for calculating Hp=2v×2p×R (mod n) from H0=2v×R (mod n) by repeating Hi=REDC(Hi-1, Hi-1)n with respect to i=1, 2, . . . , p (where p represents an integer satisfying the condition 2p?(m×k)/v>2p?1, REDC represents the Montgomery modular multiplication REDC(a, b)n=a×b×R?1 (mod n), and xˆi represents exponential computation xi); and a third step for calculating Hp=R2 (mod n) by calculating Hp=REDC(Hp, g)n with respect to Hp obtained in the second step when 2p>(m×k)/v (where g=2k×E(p,m,k), E(p, m, k)=2×m?(v×2p)/k) and finally outputting Hp as R2 (mod n).
    Type: Application
    Filed: September 21, 2005
    Publication date: October 19, 2006
    Applicant: FUJITSU LIMITED
    Inventors: Kouichi Itoh, Masahiko Takenaka, Naoya Torii
  • Publication number: 20060213713
    Abstract: An all-wheel-drive vehicle in which flexibility in setting the diameter of a driven gear is increased. In an all-wheel-drive vehicle in which an engine drives a rear wheel and also drives a hydraulic pump, and oil pressure generated by the hydraulic pump is supplied to a hydraulic motor for driving a front wheel. A front wheel hub provided on the front wheel is formed into a cup-shaped hub provided with a recess portion covered by a cover. The hydraulic motor is supported by the cover. A drive gear is provided on an output shaft of the hydraulic motor and a driven gear is provided in the recess portion of the hub with the driven gear being provided on the side of an axle.
    Type: Application
    Filed: March 21, 2006
    Publication date: September 28, 2006
    Inventor: Masahiko Takenaka
  • Patent number: 7065788
    Abstract: Ciphertext X and a constant C having relationships C>p and C>q with respect to secret keys p and q are input, and correction values C?dp and C?dq (dp=d mod (p?1), dq=d mod (q?1)) are obtained. Then, the ciphertext X is multiplied by the constant C. A remainder operation using the secret key p or q as a remainder value is conducted with respect to the multiplication result. A modular exponentiation operation based on a Chinese remainder theorem is conducted with respect to the remainder operation result, and a correction operation using a correction value C?dp or C?dq is conducted. Thereafter, plaintext Y before being encrypted is calculated.
    Type: Grant
    Filed: October 24, 2002
    Date of Patent: June 20, 2006
    Assignee: Fujitsu Limited
    Inventors: Jun Yajima, Kouichi Itoh, Masahiko Takenaka, Naoya Torii
  • Patent number: 7044253
    Abstract: A low floor vehicle is a scooter-type motorcycle in which a power unit with a longitudinal V-type engine is mounted below a low floor. The power unit is substantially U-shaped when the power unit is viewed from the top by configuring the transmission unit of the power unit so that the transmission unit is connected to the engine on one side of the V-type engine, is extended backward on one side of the vehicle and drives a chain drive mechanism so as to drive a rear wheel from the other side of the vehicle in the vicinity of a pivot of a swing arm for the rear wheel. A first exhaust pipe connected to a rear cylinder in a bank of the V-type engine is extended backward from the cylinder, the rear end is extended downward via space which is an opening substantially U-shaped when the opening is viewed from the top, the lower end is extended backward and the rear end is connected to a second exhaust pipe connected to a front cylinder in the bank of the V-type engine.
    Type: Grant
    Filed: September 18, 2003
    Date of Patent: May 16, 2006
    Assignee: Honda Giken Kogyo Kabushiki Kaisha
    Inventors: Masahiko Takenaka, Yoichi Inayama
  • Publication number: 20060093137
    Abstract: An elliptic curve cryptosystem apparatus performing an elliptic curve cryptosystem process has a coordinate transforming unit for transforming coordinates (X:Y:Z) on a point P on an elliptic curve over a finite field GF(pˆm) to coordinates (r1×(X?s1):r2×(Y?s2):r3×(Z?s3)) (where, p is a prime number, m is an integer not less than 1, r1, r2 and r3 are integers not less than 1 and not larger than (p?1), s1, s2 and s3 are integer not less than 0 and not larger than (p?1), and a code “ˆ” represents power), and a scalar multiplication operating unit for performing scalar multiplication on the point on the elliptic curve transformed by the coordinate transforming unit, wherein at least one of the parameters s1, s2 and s3 has a value other than 0. The apparatus can perform the scalar multiplication in the elliptic curve cryptosystem, with resistance to side channel attacks.
    Type: Application
    Filed: December 16, 2005
    Publication date: May 4, 2006
    Applicant: FUJITSU LIMITED
    Inventors: Tetsuya Izu, Kouichi Itoh, Masahiko Takenaka, Naoya Torii
  • Publication number: 20060085857
    Abstract: In this system, a monitor unit monitors outbound communications through a network interface. A process designation unit designates a process 2X which has generated communications. A process tree obtaining unit obtains and outputs process tree information for designation of an upper process to the process 2X. A discrimination unit refers to an illegal rule file for definition of an illegal process by a combination of a process and an upper process which have generated communications, and determines whether or not a process 2X is illegal according to communications information, process information, and process tree information. A process stop unit stops a process 2X determined to be illegal. A notification unit notifies a user of the stop of the process 2X.
    Type: Application
    Filed: January 25, 2005
    Publication date: April 20, 2006
    Applicant: Fujitsu Limited
    Inventors: Kazumasa Omote, Masahiko Takenaka, Satoru Torii
  • Patent number: 6956951
    Abstract: Intermediate data ai, bi, ci, and di are prepared by an intermediate data preparing equipment 4 from a cryptographic key through a nonlinear type function operation and the like, an extended key preparing equipment 5 selects a [Xr], b [Yr], c [Zr], and d [Wr] corresponding to the number of stages r from the intermediate data, and rearranges the data as well as conducts that of bit operation to prepare extended keys, whereby an extended key preparing apparatus by which an extended key required in the case where common key cryptosystem is applied can be safely prepared at a high speed, a process for preparing such an extended key, and a recording medium used therefor are provided.
    Type: Grant
    Filed: March 20, 2001
    Date of Patent: October 18, 2005
    Assignee: Fujitsu Limited
    Inventors: Takeshi Shimoyama, Koichi Ito, Masahiko Takenaka, Naoya Torii, Jun Yajima, Hitoshi Yanami, Kazuhiro Yokoyama
  • Publication number: 20050165875
    Abstract: An arithmetic device for Montgomery modular multiplication which quickly calculates a parameter ND with a large number of effective lower bits. The device comprises an ND generator, a multiplication-accumulation (MAC) operator, and a sum data store. The ND generator produces effective lower bits of ND at a rate of k bits per clock cycle, with reference to lower k bits of a variable S, as well as to lower k bits of an odd positive integer N. The MAC operator multiplies the produced k-bit ND value by N and adds the resulting product to S. The sum data store stores the variable S, which is updated with the output of the MAC operator, with its bits shifted right by k bits, for use by the ND generator in the subsequent clock cycle.
    Type: Application
    Filed: July 13, 2004
    Publication date: July 28, 2005
    Inventors: Kenji Mukaida, Masahiko Takenaka, Naoya Torii, Shoichi Masui
  • Publication number: 20050165876
    Abstract: A multiple-word multiplication-accumulation circuit suitable for use with a single-port memory. The circuit is composed of a multiplication-accumulation (MAC) operator and surrounding registers. The MAC operator has multiplicand and multiplier input ports with different bit widths to calculate a sum of products of multiple-word data read out of a memory. The registers serve as buffer storage of multiple-word data to be supplied to individual input ports of the MAC operator. The amount of data supplied to the MAC operator in each clock cycle is adjusted such that total amount of data consumed and produced by the MAC operator in one clock cycle will be equal to or smaller than the maximum amount of data that the memory can transfer in one clock cycle. This feature enables the use of a bandwidth-limited single-port memory, without causing adverse effect on the efficiency of MAC operator usage.
    Type: Application
    Filed: July 26, 2004
    Publication date: July 28, 2005
    Inventors: Kenji Mukaida, Masahiko Takenaka, Naoya Torii, Shoichi Masui
  • Publication number: 20050152541
    Abstract: An encryption device (FIG. 15) performs elliptic curve encryption using a secret key. The encryption device includes: operation means (ECDBL, ECADD) for performing scalar multiplication of a point on an elliptic curve; storage (T[0]-T[2]) having a plurality of data storing areas; and means (SEL) for determining, in accordance with a bit sequence of a given value (d) and with a random value (RNG), an address of one of the plurality of data storage areas that is to be coupled to the operation means for each scalar multiplication.
    Type: Application
    Filed: January 31, 2005
    Publication date: July 14, 2005
    Applicant: FUJITSU LIMITED
    Inventors: Masahiko Takenaka, Tetsuya Izu, Kouichi Itoh, Naoya Torii
  • Patent number: 6829592
    Abstract: When a user works data required for allowance for the use thereof, the work processing is carried out by utilizing an exclusive work processing device. Thereafter, only the data of work information indicating what kind of working has been made to the original data (for example, differential static image data indicating a difference between the original static image required for allowance for the use and the static image after having been worked) is stored, whereby the use without permission of the data is prevented.
    Type: Grant
    Filed: December 30, 1997
    Date of Patent: December 7, 2004
    Assignee: Fujitsu Limited
    Inventors: Takayuki Hasebe, Naoya Torii, Masahiko Takenaka, Souichi Okada, Yuji Kijima
  • Publication number: 20040129482
    Abstract: A low floor vehicle is a scooter-type motorcycle in which a power unit with a longitudinal V-type engine is mounted below a low floor. The power unit is substantially U-shaped when the power unit is viewed from the top by configuring the transmission unit so that the transmission unit is connected to the engine on one side of the V-type engine, is extended backward on one side of the vehicle and drives a rear wheel from the other side of the vehicle in the vicinity of a pivot of a swing arm for the rear wheel. A first exhaust pipe connected to a rear cylinder in a bank of the V-type engine is extended backward from the cylinder, the rear end is extended downward via space which is an opening substantially U-shaped when the opening is viewed from the top, the lower end is extended backward and the rear end is connected to a second exhaust pipe connected to a front cylinder in the bank of the V-type engine.
    Type: Application
    Filed: September 18, 2003
    Publication date: July 8, 2004
    Applicant: HONDA GIKEN KOGYO KABUSHIKI KAISHA
    Inventors: Masahiko Takenaka, Yoichi Inayama
  • Publication number: 20040124029
    Abstract: In a low floor type vehicle 10, a banking angle &thgr;1 of a longitudinal V-type engine 100 mounted below a low floor is set to an angle equal to or exceeding approximately 90°. The V-type engine is arranged with a bisector L1 of the banking angle directed toward a head pipe 21 of a body frame 20. The body frame is composed of a pair of right and left upper frames 22 extended backward and downward from the head pipe and a pair of right and left down frames 23 extended downward from the head pipe and coupled to the front of a crankcase 104 of the V-type engine and is a diamond type frame from which the V-type engine can be suspended.
    Type: Application
    Filed: September 18, 2003
    Publication date: July 1, 2004
    Applicant: HONDA GIKEN KOGYO KABUSHIKI KAISHA
    Inventors: Masahiko Takenaka, Hideki Hayashi