Wakaha OGATA


CCA-Secure Leakage-Resilient Identity-Based Encryption without q-Type Assumptions
Toi TOMITA Wakaha OGATA Kaoru KUROSAWA Ryo KUWAYAMA 
Publication:   
Publication Date: 2020/10/01
Vol. E103-A  No. 10  pp. 1157-1166
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: cryptography
Keyword: 
identity-based encryptionleakage-resilienceCCA-security
 Summary | Full Text:PDF

No-Dictionary Searchable Symmetric Encryption
Wakaha OGATA Kaoru KUROSAWA 
Publication:   
Publication Date: 2019/01/01
Vol. E102-A  No. 1  pp. 114-124
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
searchable symmetric encryptiondictionaryverifiablesearch pattern
 Summary | Full Text:PDF

Multi-Divisible On-Line/Off-Line Encryptions
Dan YAMAMOTO Wakaha OGATA 
Publication:   
Publication Date: 2017/01/01
Vol. E100-A  No. 1  pp. 91-102
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
public-key encryptionon-line/off-line encryptiondivisiblemulti-user settingKEM
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Computationally Secure Verifiable Secret Sharing Scheme for Distributing Many Secrets
Wakaha OGATA Toshinori ARAKI 
Publication:   
Publication Date: 2017/01/01
Vol. E100-A  No. 1  pp. 103-114
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
secret sharingmulti-secret sharingon-line secret sharingverifiable secret sharingcomputational security
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Secret Sharing with Share-Conversion: Achieving Small Share-Size and Extendibility to Multiparty Computation
Ryo KIKUCHI Koji CHIDA Dai IKARASHI Wakaha OGATA Koki HAMADA Katsumi TAKAHASHI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2015/01/01
Vol. E98-A  No. 1  pp. 213-222
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Foundation
Keyword: 
secret sharing schememultiparty computationcode-efficiency
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Certificateless Aggregate Signature Schemes with Improved Security
Nguyen Quoc VIET Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2015/01/01
Vol. E98-A  No. 1  pp. 92-99
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Public Key Based Cryptography
Keyword: 
certificateless signatureaggregate signaturecoalition attack
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Cheating Detectable Secret Sharing Schemes for Random Bit Strings
Wakaha OGATA Toshinori ARAKI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2013/11/01
Vol. E96-A  No. 11  pp. 2230-2234
Type of Manuscript:  PAPER
Category: Cryptography and Information Security
Keyword: 
secret sharingcheating detection
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Undeniable and Unpretendable Signatures
Le Trieu PHONG Kaoru KUROSAWA Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2012/01/01
Vol. E95-A  No. 1  pp. 138-150
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Authentication
Keyword: 
anonymityundeniable signaturesselective/all conversionunpretendable signaturesanonymous auction
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A Simple and Efficient Secret Sharing Scheme Secure against Cheating
Toshinori ARAKI Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2011/06/01
Vol. E94-A  No. 6  pp. 1338-1345
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
secret sharingcheating detection
 Summary | Full Text:PDF

Provably Secure On-Line Secret Sharing Scheme
Tatsumi OBA Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2011/01/01
Vol. E94-A  No. 1  pp. 139-149
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Secure Protocol
Keyword: 
secret sharingon-line secret sharingpublic bulletin boardprovably secure
 Summary | Full Text:PDF

New RSA-Based (Selectively) Convertible Undeniable Signature Schemes
Le Trieu PHONG Kaoru KUROSAWA Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2010/01/01
Vol. E93-A  No. 1  pp. 63-75
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Digital Signature
Keyword: 
RSAundeniable signatureselective/all conversionstandard model
 Summary | Full Text:PDF

Efficient Almost Secure 1-Round Message Transmission Schemes for 3t+1 Channels
Toshinori ARAKI Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2010/01/01
Vol. E93-A  No. 1  pp. 126-135
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Secure Protocol
Keyword: 
unconditionally secure message transmissionsecret sharing
 Summary | Full Text:PDF

New Identity-Based Blind Signature and Blind Decryption Scheme in the Standard Model
Le Trieu PHONG Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2009/08/01
Vol. E92-A  No. 8  pp. 1822-1835
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: Theory
Keyword: 
blind HIBEidentity-based blind signatureblind decryptionprovable securitystandard model
 Summary | Full Text:PDF

Collision-Based Power Attack for RSA with Small Public Exponent
Kouichi ITOH Dai YAMAMOTO Jun YAJIMA Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Information and Systems
Publication Date: 2009/05/01
Vol. E92-D  No. 5  pp. 897-908
Type of Manuscript:  Special Section PAPER (Special Section on Information and Communication System Security)
Category: Implementation Issues
Keyword: 
power attackcollision attackSPADPARSAwindow methodcountermeasure
 Summary | Full Text:PDF

Forgery Attacks on Time-Stamp, Signed PDF and X.509 Certificate
Kouichi ITOH Tetsuya IZU Wakaha OGATA Takeshi SHIMOYAMA Masahiko TAKENAKA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2009/01/01
Vol. E92-A  No. 1  pp. 67-75
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Digital Signature
Keyword: 
Bleichenbacher's forgery attackRSASSA-PKCS-v1_5time-stampPDFX.509 certificateAcrobatAcrobat Reader
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Relationship between Standard Model Plaintext Awareness and Message Hiding
Isamu TERANISHI Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2008/01/01
Vol. E91-A  No. 1  pp. 244-261
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Security Notions
Keyword: 
plaintext awarenessstandard model
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General Conversion for Obtaining Strongly Existentially Unforgeable Signatures
Isamu TERANISHI Takuro OYAMA Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2008/01/01
Vol. E91-A  No. 1  pp. 94-106
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Signatures
Keyword: 
signature schemestrong unforgeabilitystandard modelchameleon commitmentchosen message security
 Summary | Full Text:PDF

Comments on the Security Proofs of Some Signature Schemes Based on Factorization
Wakaha OGATA Naoya MATSUMOTO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2007/02/01
Vol. E90-A  No. 2  pp. 526-530
Type of Manuscript:  LETTER
Category: Information Security
Keyword: 
digital signatureRabin-type signaturerandom oracle modelsimulationfactorization
 Summary | Full Text:PDF

A General Model of Structured Multisignatures with Message Flexibility
Dan YAMAMOTO Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2007/01/01
Vol. E90-A  No. 1  pp. 83-90
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Signatures
Keyword: 
multisignaturesaggregate signaturesbilinear mapsrandom oracle model
 Summary | Full Text:PDF

On Some Variations of Kurosawa-Desmedt Public-Key Encryption Scheme
Le Trieu PHONG Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2007/01/01
Vol. E90-A  No. 1  pp. 226-230
Type of Manuscript:  Special Section LETTER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
hybrid encryptionstandard modelDDH assumptionIND-CCA
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Efficient Divisible Voting Scheme
Natsuki ISHIDA Shin'ichiro MATSUO Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2005/01/01
Vol. E88-A  No. 1  pp. 230-238
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Application
Keyword: 
secure electronic votinghomomorphic encryption
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k out of n Oblivious Transfer without Random Oracles
Wakaha OGATA Ryota SASAHARA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2004/01/01
Vol. E87-A  No. 1  pp. 147-151
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Protocol
Keyword: 
oblivious transfer protocolrandom oracle model
 Summary | Full Text:PDF

Electronic Ticket Scheme for ITS
Shin'ichiro MATSUO Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2003/01/01
Vol. E86-A  No. 1  pp. 142-150
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Protocols etc.
Keyword: 
ITSelectronic ticketelectronic money
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Matching Oblivious Transfer: How to Exchange Valuable Data
Shin'ichiro MATSUO Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2003/01/01
Vol. E86-A  No. 1  pp. 189-193
Type of Manuscript:  Special Section LETTER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
oblivious transfermultiparty protocolelectronic market and matching
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On the Practical Secret Sharing Scheme
Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2001/01/01
Vol. E84-A  No. 1  pp. 256-261
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
secret sharing schemeramp schemecheating of participantshare size
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Analysis on Secret Sharing Schemes with Non-Graphical Access Structures
Koji OKADA Wakaha OGATA Keiichi SAKANO Kaoru KUROSAWA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1997/01/25
Vol. E80-A  No. 1  pp. 85-89
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
secret sharingshare sizenon-graphical
 Summary | Full Text:PDF

Reshufflable and Laziness Tolerant Mental Card Game Protocol
Kaoru KUROSAWA Yutaka KATAYAMA Wakaha OGATA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1997/01/25
Vol. E80-A  No. 1  pp. 72-78
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
mental pokerzero knowledgemultiparty protocolprobabilistic encryptionlaziness tolerant
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4-Move Perfect ZKIP for Some Promise Problems
Kaoru KUROSAWA Wakaha OGATA Shigeo TSUJII 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1995/01/25
Vol. E78-A  No. 1  pp. 34-41
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
perfect ZKIPpromise problempromised BPP
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On Claw Free Families
Wakaha OGATA Kaoru KUROSAWA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1994/01/25
Vol. E77-A  No. 1  pp. 72-80
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
claw freeone-way functionhomomorphic propertydigital signaturehash function
 Summary | Full Text:PDF