Keita EMURA


Generic Constructions for Fully Secure Revocable Attribute-Based Encryption
Kotoko YAMADA Nuttapong ATTRAPADUNG Keita EMURA Goichiro HANAOKA Keisuke TANAKA 
Publication:   
Publication Date: 2018/09/01
Vol. E101-A  No. 9  pp. 1456-1472
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
revocable attribute-based encryptionpair encodingidentity-based revocationdoubly spatial encryption
 Summary | Full Text:PDF(1.9MB)

Group Signature with Deniability: How to Disavow a Signature
Ai ISHIDA Keita EMURA Goichiro HANAOKA Yusuke SAKAI Keisuke TANAKA 
Publication:   
Publication Date: 2017/09/01
Vol. E100-A  No. 9  pp. 1825-1837
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
group signaturedeniabilitynon-interactive zero-knowledge proofbilinear map
 Summary | Full Text:PDF(1.5MB)

Semi-Generic Transformation of Revocable Hierarchical Identity-Based Encryption and Its DBDH Instantiation
Keita EMURA Jae Hong SEO Taek-Young YOUN 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2016/01/01
Vol. E99-A  No. 1  pp. 83-91
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: 
Keyword: 
revocable hierarchical identity-based encryptionsemi-generic transformation
 Summary | Full Text:PDF(860.1KB)

Disavowable Public Key Encryption with Non-Interactive Opening
Ai ISHIDA Keita EMURA Goichiro HANAOKA Yusuke SAKAI Keisuke TANAKA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2015/12/01
Vol. E98-A  No. 12  pp. 2446-2455
Type of Manuscript:  Special Section PAPER (Special Section on Information Theory and Its Applications)
Category: Cryptography and Information Security
Keyword: 
public key encryption with non-interactive openingdisavowabilitynon-interactive zero-knowledge proof
 Summary | Full Text:PDF(1.4MB)

Revocable Identity-Based Encryption with Rejoin Functionality
Jae Hong SEO Keita EMURA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2014/08/01
Vol. E97-A  No. 8  pp. 1806-1809
Type of Manuscript:  LETTER
Category: Cryptography and Information Security
Keyword: 
Revocable Identity-Based Encryptionscalabilityrejoin functionality
 Summary | Full Text:PDF(102.6KB)

On Discrete Logarithm Based Additively Homomorphic Encryption
Jae Hong SEO Keita EMURA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2013/11/01
Vol. E96-A  No. 11  pp. 2286-2289
Type of Manuscript:  LETTER
Category: Cryptography and Information Security
Keyword: 
additive homomorphic encryptiondiscrete logarithm problemElGamal encryption
 Summary | Full Text:PDF(83.2KB)

A Remark on “ Efficient Revocable ID-Based Encryption with a Public Channel”
Jae Hong SEO Keita EMURA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2013/11/01
Vol. E96-A  No. 11  pp. 2282-2285
Type of Manuscript:  LETTER
Category: Cryptography and Information Security
Keyword: 
revocable identity-based encryptionscalabilitydecryption key exposure resilience
 Summary | Full Text:PDF(93.8KB)

Methods for Restricting Message Space in Public-Key Encryption
Yusuke SAKAI Keita EMURA Goichiro HANAOKA Yutaka KAWAI Kazumasa OMOTE 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2013/06/01
Vol. E96-A  No. 6  pp. 1156-1168
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
public-key encryptionabuse detectionformat checking
 Summary | Full Text:PDF(978.9KB)

A Timed-Release Proxy Re-Encryption Scheme
Keita EMURA Atsuko MIYAJI Kazumasa OMOTE 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2011/08/01
Vol. E94-A  No. 8  pp. 1682-1695
Type of Manuscript:  PAPER
Category: Cryptography and Information Security
Keyword: 
timed-release encryptionproxy re-encryption
 Summary | Full Text:PDF(397.7KB)