Title:
FORWARD SECURE ELECTRONIC SIGNATURE METHOD, APPARATUS THEREFOR, PROGRAM AND RECORDING MEDIUM THEREFOR
Document Type and Number:
Japanese Patent JP3939586
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To completely update a session key efficiently with a little information without limiting the number of times of updating.
SOLUTION: Random numbers (s) and x (element of Zq) are generated, master verification keys h=gs mod p and y=gx mod p are calculated and disclosed, and a random number (u) is generated to calculate a=gu, e=H(a, h, y, g) and v=u-es mod q. When the session verification key and a signature key are defined as (e, v, g) and (s, x), a random number w (element of Zq) is generated with respect to a message (m) to calculate b=gw, c=H(b, h, y, g, m) and z=w-cx mod q, and signatures (c) and (z) are generated. When updating the session key, a random number r (element of Zq) is generated to define g'=gr, s'=r-1s mod q, x'=r-1s mod q, a'=g'u', e'=H(a', h, y, g'), v'=u'-e's' mod q, (S', x') and (e', v', g') as updated keys.
Inventors:
Wisteria Saki Eiichiro
Application Number:
JP2002132765A
Publication Date:
July 04, 2007
Filing Date:
May 08, 2002
Export Citation:
Assignee:
Nippon Telegraph and Telephone Corporation
International Classes:
H04L9/32; (IPC1-7): H04L9/32
Other References:
M.Bellare and S.Miner,"A forward-secure digital signature scheme",Advances in Cryptoloty CRYPTO'99,Springer-Verlag,1999年10月13日,p.431-448
Attorney, Agent or Firm:
Naoki Nakao
Taku Kusano
Yukio Nakamura
Minoru Inagaki
Taku Kusano
Yukio Nakamura
Minoru Inagaki