Kazuo OHTA


Ciphertext-Policy Delegatable Hidden Vector Encryption and Its Application
Mitsuhiro HATTORI Takato HIRANO Takashi ITO Nori MATSUDA Takumi MORI Yusuke SAKAI Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2013/01/01
Vol. E96-A  No. 1  pp. 53-67
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Public Key Based Protocols
Keyword: 
hidden vector encryptionsearchable encryptionpairing-based cryptography
 Summary | Full Text:PDF(1.2MB)

A New Type of Fault-Based Attack: Fault Behavior Analysis
Yang LI Kazuo OHTA Kazuo SAKIYAMA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2013/01/01
Vol. E96-A  No. 1  pp. 177-184
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Implementation
Keyword: 
fault-based attackAESfaulty behaviorphysical attacksmasking
 Summary | Full Text:PDF(1.2MB)

Toward Effective Countermeasures against an Improved Fault Sensitivity Analysis
Yang LI Kazuo OHTA Kazuo SAKIYAMA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2012/01/01
Vol. E95-A  No. 1  pp. 234-241
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Implementation
Keyword: 
side-channel attacksfault sensitivity analysiscountermeasuresWDDLAES
 Summary | Full Text:PDF(558.1KB)

Meet-in-the-Middle (Second) Preimage Attacks on Two Double-Branch Hash Functions RIPEMD and RIPEMD-128
Lei WANG Yu SASAKI Wataru KOMATSUBARA Kazuo SAKIYAMA Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2012/01/01
Vol. E95-A  No. 1  pp. 100-110
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Hash Function
Keyword: 
RIPEMDRIPEMD-128meet-in-the-middleone-message-word local collision
 Summary | Full Text:PDF(1.5MB)

Universally Composable NBAC-Based Fair Voucher Exchange for Mobile Environments
Kazuki YONEYAMA Masayuki TERADA Sadayuki HONGO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2011/06/01
Vol. E94-A  No. 6  pp. 1263-1273
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
fairnessfair exchangeelectronic voucheruniversal composabilitynon-blocking atomic commitment
 Summary | Full Text:PDF(419.5KB)

How to Shorten a Ciphertext of Reproducible Key Encapsulation Mechanisms in the Random Oracle Model
Yusuke SAKAI Goichiro HANAOKA Kaoru KUROSAWA Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2011/06/01
Vol. E94-A  No. 6  pp. 1293-1305
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
public key encryptionchosen-ciphertext securitykey encapsulation mechanism
 Summary | Full Text:PDF(435.6KB)

Ultra-Wideband Array Antenna Utilizing Novel Scanning System with Tapped Delay Lines for Short Range Radar
Fuminori SAKAI Kazuo OHTA Kunio SAWAYA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2011/05/01
Vol. E94-B  No. 5  pp. 1194-1200
Type of Manuscript:  Special Section PAPER (Special Section on Antenna and Propagation Technologies Contributing to Diversification of Wireless Technologies)
Category: Antennas and Antenna Measurement
Keyword: 
array antennadelay lineimpulsescanning antennaultra-wideband
 Summary | Full Text:PDF(2.1MB)

An Efficient Authentication for Lightweight Devices by Perfecting Zero-Knowledgeness
Bagus SANTOSO Kazuo OHTA Kazuo SAKIYAMA Goichiro HANAOKA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2011/01/01
Vol. E94-A  No. 1  pp. 92-103
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Identification
Keyword: 
identification schemeRFIDzero-knowledgeimpersonation
 Summary | Full Text:PDF(736.7KB)

Security of Cryptosystems Using Merkle-Damgård in the Random Oracle Model
Yusuke NAITO Kazuki YONEYAMA Lei WANG Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2011/01/01
Vol. E94-A  No. 1  pp. 57-70
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Public Key Cryptography
Keyword: 
indifferentiabilityMerkle-Damgård hash functionvariants of random oraclecryptosystems security
 Summary | Full Text:PDF(657.3KB)

Power Analysis against a DPA-Resistant S-Box Implementation Based on the Fourier Transform
Yang LI Kazuo SAKIYAMA Shinichi KAWAMURA Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2011/01/01
Vol. E94-A  No. 1  pp. 191-199
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Implementation
Keyword: 
side channel attacksmaskingFourier transforms-boxprobability density function
 Summary | Full Text:PDF(2.1MB)

Extension of Secret Handshake Protocols with Multiple Groups in Monotone Condition
Yutaka KAWAI Shotaro TANNO Takahiro KONDO Kazuki YONEYAMA Kazuo OHTA Noboru KUNIHIRO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2010/06/01
Vol. E93-A  No. 6  pp. 1122-1131
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: Cryptography and Information Security
Keyword: 
secret handshake with multiple groupsprivacy preserving authenticationanonymitymonotone condition
 Summary | Full Text:PDF(1.3MB)

Cryptanalysis of Two MD5-Based Authentication Protocols: APOP and NMAC
Lei WANG Kazuo OHTA Yu SASAKI Kazuo SAKIYAMA Noboru KUNIHIRO 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2010/05/01
Vol. E93-D  No. 5  pp. 1087-1095
Type of Manuscript:  Special Section PAPER (Special Section on Information and Communication System Security)
Category: 
Keyword: 
authentication protocolAPOPNMACMD5
 Summary | Full Text:PDF(317.2KB)

Practical Password Recovery Attacks on MD4 Based Prefix and Hybrid Authentication Protocols
Yu SASAKI Lei WANG Kazuo OHTA Kazumaro AOKI Noboru KUNIHIRO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2010/01/01
Vol. E93-A  No. 1  pp. 84-92
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Hash Function
Keyword: 
challenge and responseprefixhybridpassword recovery attacklocal collisionhash functionMD4
 Summary | Full Text:PDF(339.7KB)

On Clock-Based Fault Analysis Attack for an AES Hardware Using RSL
Kazuo SAKIYAMA Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2010/01/01
Vol. E93-A  No. 1  pp. 172-179
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Cryptanalysis
Keyword: 
fault analysisrandom switching logicAESclock-based fault analysis attack
 Summary | Full Text:PDF(438.1KB)

Leaky Random Oracle
Kazuki YONEYAMA Satoshi MIYAGAWA Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2009/08/01
Vol. E92-A  No. 8  pp. 1795-1807
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: Theory
Keyword: 
hash functionrandom oracle modelstandard modelprovable securityleakage
 Summary | Full Text:PDF(257.5KB)

Attribute-Based Encryption with Partially Hidden Ciphertext Policies
Takashi NISHIDE Kazuki YONEYAMA Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2009/01/01
Vol. E92-A  No. 1  pp. 22-32
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Public Key Cryptography
Keyword: 
attribute-based encryptionrecipient anonymityaccess control on encrypted data
 Summary | Full Text:PDF(255.5KB)

A Strict Evaluation on the Number of Conditions for SHA-1 Collision Search
Jun YAJIMA Terutoshi IWASAKI Yusuke NAITO Yu SASAKI Takeshi SHIMOYAMA Thomas PEYRIN Noboru KUNIHIRO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2009/01/01
Vol. E92-A  No. 1  pp. 87-95
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Hash Function
Keyword: 
hash functioncollision searchSHA-1disturbance vector
 Summary | Full Text:PDF(330.1KB)

Extended Password Recovery Attacks against APOP, SIP, and Digest Authentication
Yu SASAKI Lei WANG Kazuo OHTA Noboru KUNIHIRO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2009/01/01
Vol. E92-A  No. 1  pp. 96-104
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Hash Function
Keyword: 
APOPSIPdigest authenticationIV bridgecollision attackhash functionMD5
 Summary | Full Text:PDF(230.4KB)

Near-Collision Attacks on MD4: Applied to MD4-Based Protocols
Lei WANG Kazuo OHTA Noboru KUNIHIRO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2009/01/01
Vol. E92-A  No. 1  pp. 76-86
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Hash Function
Keyword: 
near-collisionMD4HMAC/NMACchallenge and responseHash(Password||Challenge)
 Summary | Full Text:PDF(287.3KB)

A New 'On the Fly' Identification Scheme: An Asymptoticity Trade-Off between ZK and Correctness
Bagus SANTOSO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2009/01/01
Vol. E92-A  No. 1  pp. 122-136
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Secure Protocol
Keyword: 
identification schemezero-knowledgeimpersonation under serial active attack
 Summary | Full Text:PDF(335.1KB)

FOREWORD
Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2009/01/01
Vol. E92-A  No. 1  pp. 1-2
Type of Manuscript:  FOREWORD
Category: 
Keyword: 
 Summary | Full Text:PDF(46.2KB)

Factorization of Square-Free Integers with High Bits Known
Bagus SANTOSO Noboru KUNIHIRO Naoki KANAYAMA Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2008/01/01
Vol. E91-A  No. 1  pp. 306-315
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Cryptanalysis
Keyword: 
factorizationlatticeCoppersmith's method
 Summary | Full Text:PDF(332.9KB)

New Message Differences for Collision Attacks on MD4 and MD5
Yu SASAKI Lei WANG Noboru KUNIHIRO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2008/01/01
Vol. E91-A  No. 1  pp. 55-63
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Hash Functions
Keyword: 
collision attackmessage differenceMD4MD5hash function
 Summary | Full Text:PDF(265KB)

Provably Secure Multisignatures in Formal Security Model and Their Optimality
Yuichi KOMANO Kazuo OHTA Atsushi SHIMBO Shinichi KAWAMURA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2008/01/01
Vol. E91-A  No. 1  pp. 107-118
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Signatures
Keyword: 
multisignaturestrapdoor one-way permutation (TOWP)claw-free permutation (CFP)provably securerandom oracle model
 Summary | Full Text:PDF(346.7KB)

Improved Collision Search for Hash Functions: New Advanced Message Modification
Yusuke NAITO Kazuo OHTA Noboru KUNIHIRO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2008/01/01
Vol. E91-A  No. 1  pp. 46-54
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Hash Functions
Keyword: 
hash functioncollision attackcollision searchadvanced message modification
 Summary | Full Text:PDF(302.9KB)

Provably Secure Untraceable Electronic Cash against Insider Attacks
Yoshikazu HANATANI Yuichi KOMANO Kazuo OHTA Noboru KUNIHIRO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2007/05/01
Vol. E90-A  No. 5  pp. 980-991
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
blind multisignatureelectronic cashprovable securityrandom oracle modelinsider attacks
 Summary | Full Text:PDF(279.5KB)

Constant-Round Multiparty Computation for Interval Test, Equality Test, and Comparison
Takashi NISHIDE Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2007/05/01
Vol. E90-A  No. 5  pp. 960-968
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
multiparty computationsecret sharingbitwise sharingcomputing with encrypted data
 Summary | Full Text:PDF(237.5KB)

Improved Collision Attacks on MD4 and MD5
Yu SASAKI Yusuke NAITO Noboru KUNIHIRO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2007/01/01
Vol. E90-A  No. 1  pp. 36-47
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Hash Functions
Keyword: 
message modificationcollision attackMD5MD4hash function
 Summary | Full Text:PDF(260.9KB)

Toward the Fair Anonymous Signatures: Deniable Ring Signatures
Yuichi KOMANO Kazuo OHTA Atsushi SHIMBO Shinichi KAWAMURA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2007/01/01
Vol. E90-A  No. 1  pp. 54-64
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Signatures
Keyword: 
group signaturesring signaturesDLPCDHDDHrandom oracle model
 Summary | Full Text:PDF(284.1KB)

Universally Composable Hierarchical Hybrid Authenticated Key Exchange
Haruki OTA Kazuki YONEYAMA Shinsaku KIYOMOTO Toshiaki TANAKA Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2007/01/01
Vol. E90-A  No. 1  pp. 139-151
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Protocols
Keyword: 
passwordDiffie-Hellmanauthenticated key exchangeuniversal composabilityhierarchical hybrid constructionMAC (Message Authentication Code)
 Summary | Full Text:PDF(334.6KB)

Visual Secret Sharing Schemes for Multiple Secret Images Allowing the Rotation of Shares
Mitsugu IWAMOTO Lei WANG Kazuki YONEYAMA Noboru KUNIHIRO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2006/05/01
Vol. E89-A  No. 5  pp. 1382-1395
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
visual secret sharing schemesvisual cryptographysecret sharing schemesmultiple secret imagesrotation of shares
 Summary | Full Text:PDF(527.7KB)

Maurer-Yacobi ID-Based Key Distribution Revisited
Noboru KUNIHIRO Wataru ABE Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2006/05/01
Vol. E89-A  No. 5  pp. 1421-1424
Type of Manuscript:  Special Section LETTER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
ID-based key distributionbaby step/giant step algorithmPohlig-Hellman algorithm
 Summary | Full Text:PDF(75.5KB)

Taxonomical Security Consideration of OAEP Variants
Yuichi KOMANO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2006/05/01
Vol. E89-A  No. 5  pp. 1233-1245
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
OAEPSAEPprovably securereductionPaddingrandom oracle
 Summary | Full Text:PDF(287.8KB)

Solutions to Security Problems of Rivest and Shamir's PayWord Scheme
Norio ADACHI Satoshi AOKI Yuichi KOMANO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2005/01/01
Vol. E88-A  No. 1  pp. 195-202
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Application
Keyword: 
micropaymentPayWord Schemedigital signaturehash chain
 Summary | Full Text:PDF(241.6KB)

Probabilistic Multi-Signature Schemes Using a One-Way Trapdoor Permutation
Kei KAWAUCHI Yuichi KOMANO Kazuo OHTA Mitsuru TADA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2004/05/01
Vol. E87-A  No. 5  pp. 1141-1153
Type of Manuscript:  Special Section LETTER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
multi-signature schemeprobabilistic signature schemeexact securityrandom oracle model
 Summary | Full Text:PDF(317.6KB)

OAEP-ES--Methodology of Universal Padding Technique--
Yuichi KOMANO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2004/01/01
Vol. E87-A  No. 1  pp. 110-119
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Asymmetric Cipher
Keyword: 
OAEPPSSuniversal paddingreductionprovably secure
 Summary | Full Text:PDF(318.2KB)

Cryptographic Works of Dr. Kenji Koyama: In Memoria
Noboru KUNIHIRO Kazuo OHTA Tatsuaki OKAMOTO Routo TERADA Yukio TSURUOKA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2001/01/01
Vol. E84-A  No. 1  pp. 108-113
Type of Manuscript:  INVITED PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
modern cryptographykey managementzero-knowledge proofelliptic curve applications
 Summary | Full Text:PDF(216.8KB)

E2--A New 128-Bit Block Cipher
Masayuki KANDA Shiho MORIAI Kazumaro AOKI Hiroki UEDA Youichi TAKASHIMA Kazuo OHTA Tsutomu MATSUMOTO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2000/01/25
Vol. E83-A  No. 1  pp. 48-59
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
encryption algorithmblock cipherE2AESdesign strategy
 Summary | Full Text:PDF(1.3MB)

Multi-Signature Schemes Secure against Active Insider Attacks
Kazuo OHTA Tatsuaki OKAMOTO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1999/01/25
Vol. E82-A  No. 1  pp. 21-31
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
digital signatureFiat-Shamir schemeSchnorr schemerandom oracle modelzero-knowledge interactive proofprovable security
 Summary | Full Text:PDF(219.6KB)

Remarks on Transformable Digital Signatures
Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1998/05/25
Vol. E81-A  No. 5  pp. 814-817
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
digital signatureblind decryptionoracle attacktransformability RSA schemeElGamal schemecommutative random-self reducible problem
 Summary | Full Text:PDF(348.9KB)

Security of the Extended Fiat-Shamir Schemes
Kazuo OHTA Tatsuaki OKAMOTO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1998/01/25
Vol. E81-A  No. 1  pp. 65-71
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
the Fiat-Shamir schemezero-knowledge proofidentificationno-transferable informationdigital signatures
 Summary | Full Text:PDF(673.4KB)

One-Time Zero-Knowledge Authentications and Their Applications to Untraceable Electronic Cash
Tatsuaki OKAMOTO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1998/01/25
Vol. E81-A  No. 1  pp. 2-10
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
electronic cashzero-knowledge proofsuntraceabilityoff-line cash
 Summary | Full Text:PDF(827.8KB)

Collision Search of a Hash Function by Using Random Mapping
Hikaru MORITA Hideki ODAGI Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1998/01/25
Vol. E81-A  No. 1  pp. 35-40
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
hash functioncollisionpseudo random functionrandom mapping
 Summary | Full Text:PDF(471.5KB)

Linear Cryptanalysis of FEAL
Kazumaro AOKI Kazuo OHTA Shiho MORIAI Mitsuru MATSUI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1998/01/25
Vol. E81-A  No. 1  pp. 88-97
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
linear cryptanalysis1R-attack2R-attackeffective key bitseffective text bitsFEAL
 Summary | Full Text:PDF(776.8KB)

Strict Evaluation of the Maximum Average of Differential Probability and the Maximum Average of Linear Probability
Kazumaro AOKI Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1997/01/25
Vol. E80-A  No. 1  pp. 2-8
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
Feistel cipherdifferential cryptanalysislinear cryptanalysisdifferential probabilitypotential of linear approximate hull
 Summary | Full Text:PDF(404.6KB)

Key-Dependency of Linear Probability of RC5
Shiho MORIAI Kazumaro AOKI Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1997/01/25
Vol. E80-A  No. 1  pp. 9-18
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
RC5linear cryptanalysislinear probabilityweak keykey-dependency
 Summary | Full Text:PDF(660.8KB)

The Best Linear Expression Search of FEAL
Shiho MORIAI Kazumaro AOKI Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1996/01/25
Vol. E79-A  No. 1  pp. 2-11
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
Linear Cryptanalysisbest linear expressionFEALsearch algorithm
 Summary | Full Text:PDF(754.8KB)

Differential-Linear Cryptanalysis of FEAL-8
Kazumaro AOKI Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1996/01/25
Vol. E79-A  No. 1  pp. 20-27
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
code breakblock cipherdifferential-linear cryptanalysisFEAL
 Summary | Full Text:PDF(561.5KB)

New Proposal and Comparison of Closure Tests--More Efficient than the CRYPTO'92 Test for DES--
Hikaru MORITA Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1994/01/25
Vol. E77-A  No. 1  pp. 15-19
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
switching closure test (SCT)cycling closure test (CCT)meet-in-the-middle closure test (MCT)DES cipher
 Summary | Full Text:PDF(413.2KB)

Message Authentication Codes and Differential Attack
Kazuo OHTA Mitsuru MATSUI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1994/01/25
Vol. E77-A  No. 1  pp. 8-14
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
 Summary | Full Text:PDF(648KB)

A Switching Closure Test to Analyze Cryptosystems
Hikaru MORITA Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1992/04/25
Vol. E75-A  No. 4  pp. 498-503
Type of Manuscript:  Special Section PAPER (Special Issue on Discrete Mathematics and Its Application)
Category: 
Keyword: 
cryptosystemgroupclosure testmeet-in-the-middle techniqueDES cipherRSA schemebirth-day paradox
 Summary | Full Text:PDF(440.9KB)

Interactive Bi-proof Systems and Undeniable Signature Schemes
Atsushi FUJIOKA Tatsuaki OKAMOTO Kazuo OHTA 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 1992/01/25
Vol. E75-D  No. 1  pp. 102-109
Type of Manuscript:  Special Section PAPER (Special Section on Theoretical Foundations of Computing)
Category: 
Keyword: 
interactive proof systemrandom self-reducibilityminimum knowledgenessdigital signature
 Summary | Full Text:PDF(644.7KB)

Abuses of Undeniable Signatures and Their Countermeasures
Kazuo OHTA Tatsuaki OKAMOTO Atsushi FUJIOKA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1991/08/25
Vol. E74-A  No. 8  pp. 2109-2113
Type of Manuscript:  Special Section PAPER (Special Issue on Cryptography and Information Security)
Category: 
Keyword: 
 Summary | Full Text:PDF(384.9KB)

Membership Authentication for Hierarchical Multigroups Using a Master Secret Key
Kazuo OHTA Tatsuaki OKAMOTO 
Publication:   IEICE TRANSACTIONS (1976-1990)
Publication Date: 1990/07/25
Vol. E73-E  No. 7  pp. 1107-1110
Type of Manuscript:  Special Section PAPER (Special Issue on Cryptography and Information Security)
Category: Authentication Techniques
Keyword: 
 Summary | Full Text:PDF(364.9KB)

The Construction of Collision Messages for Hash Functions
Masahiko IWATA Kazuo OHTA Shoji MIYAGUCHI 
Publication:   IEICE TRANSACTIONS (1976-1990)
Publication Date: 1990/07/25
Vol. E73-E  No. 7  pp. 1100-1106
Type of Manuscript:  Special Section PAPER (Special Issue on Cryptography and Information Security)
Category: Authentication Techniques
Keyword: 
 Summary | Full Text:PDF(453.4KB)