Koh-ichi NAGAO


A Weil Descent Attack against Elliptic Curve Cryptosystems over Quartic Extension Fields
Seigo ARITA Kazuto MATSUO Koh-ichi NAGAO Mahoro SHIMURA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2006/05/01
Vol. E89-A  No. 5  pp. 1246-1254
Type of Manuscript:  Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
elliptic curve cryptosystemshyperelliptic curve cryptosystemsWeil descent attackScholten formCab curves
 Summary | Full Text:PDF(285.6KB)

Analysis of Baby-Step Giant-Step Algorithms for Non-uniform Distributions
Koh-ichi NAGAO Shigenori UCHIYAMA Naoki KANAYAMA Kazuto MATSUO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2004/01/01
Vol. E87-A  No. 1  pp. 10-17
Type of Manuscript:  Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Fundamental
Keyword: 
baby-step giant-step algorithmfinite group
 Summary | Full Text:PDF(298.6KB)

Generating Secure Genus Two Hyperelliptic Curves Using Elkies' Point Counting Algorithm
Naoki KANAYAMA Koh-ichi NAGAO Shigenori UCHIYAMA 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2003/04/01
Vol. E86-A  No. 4  pp. 919-927
Type of Manuscript:  PAPER
Category: Information Security
Keyword: 
hyperelliptic curveBSGSpoint counting
 Summary | Full Text:PDF(279.8KB)

On the Euclidean Algorithm of Polynomials
Yuichi FUTA Koh-ichi NAGAO 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 2001/05/01
Vol. E84-A  No. 5  pp. 1261-1265
Type of Manuscript:  Special Section LETTER (Special Section on Discrete Mathematics and Its Applications)
Category: 
Keyword: 
Euclidean algorithmpolynomialKaratsuba's algorithm
 Summary | Full Text:PDF(147.8KB)