Keita XAGAWA


Key-Private Proxy Re-Encryption from Lattices, Revisited
Ryo NISHIMAKI Keita XAGAWA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2015/01/01
Vol. E98-A  No. 1  pp. 100-116
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Public Key Based Cryptography
Keyword: 
proxy re-encryptionkey privacyanonymitylattices
 Summary | Full Text:PDF(616.6KB)

Non-malleable Multiple Public-Key Encryption
Atsushi FUJIOKA Eiichiro FUJISAKI Keita XAGAWA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2014/06/01
Vol. E97-A  No. 6  pp. 1318-1334
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
Multiple public-key encryptionNon-malleabilityAdversarially chosen public-key attacksThreshold public-key encryptionand Completely non-malleable public-key encryption.
 Summary | Full Text:PDF(715.9KB)

Secure Hierarchical Identity-Based Identification without Random Oracles
Atsushi FUJIOKA Taiichi SAITO Keita XAGAWA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2014/06/01
Vol. E97-A  No. 6  pp. 1307-1317
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
hierarchical identity-based identificationimpersonation under active and concurrent attackscomputational Diffie-Hellman assumptionRSA assumption
 Summary | Full Text:PDF(652.3KB)