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Author

信一 川村

Bio: 信一 川村 is an academic researcher. The author has contributed to research in topics: Multiplication & Key (cryptography). The author has an hindex of 5, co-authored 12 publications receiving 103 citations.

Papers
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Patent
20 Aug 1998
TL;DR: In this article, the reverse transposition P-1 of a mask was used to make the cryptanalysis by differential power analysis difficult without changing the results of the data encryption processing of the conventional encryption apparatus.
Abstract: PROBLEM TO BE SOLVED: To provide a means which makes the cryptanalysis by a DPA (differential power analysis) difficult without changing the results of the data encryption processing of the conventional encryption apparatus, decryption apparatus, encryption means and decryption means. SOLUTION: Each stage function of a data agitation section is provided with a pair of the pattern of a mask (a) and the mask pattern which is a reversal of its bit. One of the pair is randomly selected by a switch SW12 every time when encryption is executed to obtain the exclusive-OR 32a of the input to an S box 29 and the selected mask pattern and to obtain the exclusive-OR 33a of the output of the S box 29 and the bit of the reverse transposition P-1 of the mask (a). The exclusive-ORs 32a, 33a are previously calculated and are recorded as a table in the S box 29. Further, the output of each stage function 5 is subjected to the exclusive-OR 43a with the mask (b) and is concealed. The influence by the mask (b) is eliminated by executing the exclusive-OR with the mask (b) again in the ensuing stage. COPYRIGHT: (C)2000,JPO

47 citations

Patent
22 Jan 2001
TL;DR: In this article, an attribute certificate is provided which includes a lot of attribute information so that they can be individually verified and can be used to realize certification and signature techniques which can be applied to various systems and contribute to development of an informationoriented society.
Abstract: PROBLEM TO BE SOLVED: To realize certification and signature techniques which can be applied to various systems and contribute to development of an information-oriented society. SOLUTION: The attribute certificate is provided which includes a lot of attribute information so that they can be individually verified. Concretely, (1) an attribute certificate CertA is a digital signature of an attribute certificate issue agency ACA which is given to a public key PA of a prover A, attribute information c1 to c8 ciphered by a key, and the total number 8 of attributes. (2) The prover A discloses attribute information a1, a3, and a6, which are related to only attributes of which the disclosure is requested, to a verifier and proves it to the verifier that disclosed attribute information a1, a3, and a6 are permitted right information. (3) Attribute information a2, a4, a5, a7, and a8 related to attributes of which the disclosure is not requested are not disclosed to the verifier at all. Thus various certificates/signatures using minimum required attributes are possible. COPYRIGHT: (C)2002,JPO

12 citations

Patent
23 Jul 1999
TL;DR: In this article, a control part for executing remainder multiplication in a product sum arithmetic circuit after dividing remainder multiplication into multiplication processing and remainder calculation processing is provided. But this control part cannot be used to enable arithmetic operation to be executed without remaking a device main body even when the extension order of an extension field of 2 is increased.
Abstract: PROBLEM TO BE SOLVED: To enable arithmetic operation to be executed without remaking a device main body even when the extension order of an extension field of 2 is increased by providing a control means for executing remainder multiplication in a product sum arithmetic circuit after dividing remainder multiplication into multiplication processing and remainder calculation processing. SOLUTION: The arithmetic unit having product sum arithmetic circuits 12, 14, 15 of multiple length is provided with a control part 5 for executing remainder multiplication in the product sum arithmetic circuits 12, 14, 15 after dividing remainder multiplication into multiplication processing and remainder calculation processing. A multiplication circuit 12 on the extension field of 2 executes a part of multiplication on the extension field of 2 by data X in a buffer X and data Y in a buffer Y and outputs result to a selector 13. The selector 13 outputs either output from an integer type multiplication circuit 11 or output from the multiplication circuit 12 on the extension field of 2 to an adding circuit 14 according to a signal S1 from the control part 5. The adding circuit 14 is composed of a full adder which adds data z in a buffer Z to selector output and outputs the result to an adding circuit 15.

9 citations

Patent
20 Jan 1999
TL;DR: In this article, an integer type multiplying circuit 11 performs integer type multiplication between data X in buffer X and data Y in buffer Y and outputs the result to a selector 13 by propagating a carry or without propagating the carry.
Abstract: PROBLEM TO BE SOLVED: To perform operation in an extension field of 2 in addition to integer type operation only by adding minimum architecture by placing a multiplying circuit in operation by propagating a carry or without propagating the carry. SOLUTION: On a coprocessor 1, an integer type multiplying circuit 11 performs integer type multiplication between data X in a buffer X and data Y in a buffer Y and outputs the result to a selector 13. A circuit 12 for multiplication in the extension field of 2 performs multiplication in the extension field of 2 by the data X and data Y and outputs the result to a selector 13. The difference between the integer operation by the integer type multiplying circuit 11 and extension field multinomial operation of 2 by the multiplying circuit 12 is based on whether or not there is a carry (carry propagation). The selector 13 is switched according to the control signal S1 from a control part 5. An adding circuit 14 and an adding circuit 15 also switch integer type addition and addition in the extension field of 2 with the control signal S1.

8 citations

Patent
27 Nov 1998
TL;DR: In this paper, the authors proposed a ciphering and deciphering device which ciphers a plain text into a cipher-text and/or decodes a ciphertext into a plain plain text.
Abstract: PROBLEM TO BE SOLVED: To provide an algorithm more efficient than a simple three-staged DES-SS and also resistant to a difference attack and a linear attack, although it configures a single encription algorithm compatible to any of DES, triple DES, and DES-SS. SOLUTION: This device is a ciphering and deciphering device 10 which ciphers a plain text 21 into a cipher-text 22 and/or decipher a cipher-text into a plain text, and is provided with a 1st ciphering and deciphering means 11 for processing by ciphering or decipher processing, a 1st substituting means 12 for substituting a data for an output of the 1st ciphering and deciphering means according to a substitution table, a 2nd ciphering and deciphering means 13 for processing an output of the 1st substituting means by ciphering or deciphering, a 2nd substituting means 14 for substituting a data for the output of the 2nd ciphering and deciphering means according to a predetermined substitution table, and a 3rd ciphering and deciphering means 15 for ciphering or deciphering an output of the 2nd substituting means.

6 citations


Cited by
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Patent
Yannis Labrou1, Jonathan R. Agre1
18 Jul 2006
TL;DR: In this paper, a secure transaction server (STS) is used to authenticate a point of sale (POS) device according to a first authentication parameter and a second authentication parameter.
Abstract: Methods and systems provide a secure transaction server (STS); provide an authentic point of sale (POS) device, according to a first authentication parameter of the STS; provide an authentic mobile purchasing device, according to a second authentication parameter of the STS; provide a short-range communication method between the POS device and the mobile purchasing device; correlate by the STS a personal identification entry (PIE) and the authentic mobile purchasing device; transmit, by the POS device, a time dependent transformed secure POS authenticable POS purchase action to the STS; input the PIE to the mobile purchasing device to transmit a time dependent transformed secure user authenticable POS purchase action to the POS device via the short-range communication method; and approve, by the STS, the POS purchase action for the POS device and for the mobile purchasing device, according to the authentic POS device, and according to the authentic mobile purchasing device and the STS correlating of the PIE and the authentic mobile purchasing device.

547 citations

Patent
29 Jul 2003
TL;DR: In this article, a system for conducting an agreement between two parties relying on a trusted third party is presented, where a first party generates a first view of the agreement and transmits the first view to the third party.
Abstract: A system for conducting an agreement between two parties relying on a trusted a third party includes a first party generating a first view of the agreement and transmitting the first view of the agreement to the third party, a second party independently generating a second view of the agreement and transmitting the second view of the agreement to the third party, a wireless network connecting the first party and the second party, and a wired or wireless network connecting the second party to the third party. The trusted third party, receives the first view of the agreement and the second view of the agreement, verifies conditions including that the identities of the parties that transmitted the agreements and that the independent views of the agreement are consistent with each other, and takes action to execute the agreement if the conditions are satisfied.

235 citations

Patent
25 Jan 2005
TL;DR: In this article, the authors present a system that securely transmits and authenticates a transaction input by a user while retaining the anonymity of the user with respect to the content of the transaction.
Abstract: A computer-based system securely transmitting and authenticating a transaction input by a user while retaining the anonymity of the user with respect to content of the transaction, including a device encoding the content of the transaction input by the user with a key known only to another device, encoding other portions of the transaction with another key known only to a secure transaction server, and sending the encoded content of the transaction and the encoded other portions of the transaction to the secure transaction server to authenticate an identity of the user of the device, wherein the secure transaction server decodes the other portions of the transaction and sends the encoded content of the transaction to the another device to be finally decoded.

102 citations

Patent
Yosef Stein1, Haim Primo1
18 Dec 2002
TL;DR: In this article, a programmable data encryption engine for performing the cipher function of an AES algorithm includes a parallel look-up table system responsive in a first mode to a first data block for implementing an AES selection function and executing the multiplicative inverse in GF -1 ( 2 8 ) and applying an affine over GF( 2 ) transformation to obtain a sub-byte transformation and in a second mode to the subbyte transformation to transform the sub-transformer to get a shift row transformation.
Abstract: A programmable data encryption engine for performing the cipher function of an advanced encryption standard ( AES ) algorithm includes a parallel look-up table system responsive in a first mode to a first data block for implementing an AES selection function and executing the multiplicative inverse in GF -1 ( 2 8 ) and applying an affine over GF( 2 ) transformation to obtain a subbyte transformation and in a second mode to the subbyte transformation to transform the subbyte transformation to obtain a shift row transformation, and a Galois field multiplier for transforming the shift row transformation to obtain a mix column transformation and add a round key resulting in an advanced encryption standard cipher function of the first data block.

100 citations

Patent
16 Oct 2007
TL;DR: In this paper, a secret information management system is defined, which consists of a secret distribution unit which secretly distributes a data key k using a (k, n) threshold secret sharing scheme and creates n distributed keys B1, B2,..., Bn in the decryption of data D input from a user terminal.
Abstract: In a secret information management system, a secret information management apparatus comprises a secret distribution unit which secretly distributes a data key k using a (k, n) threshold secret sharing scheme and creates n distributed keys B1, B2, . . . , Bn in the decryption of data D input from a user terminal, an encryption unit which creates n encrypted distributed keys EP1(B1), EP2(B2) . . . , EPn(Bn) using n distributed manager public keys P1, P2, . . . Pn, and an encrypted data storage unit which stores encrypted data EK(D), an encrypted data key EPx(K) and the n encrypted distributed keys in association with each other.

69 citations