Title: Calculation method, calculation equipment and computer program
Application Number: 200510089045 Application Date: 2005.08.03
Publication Number: 1841443 Publication Date: 2006.10.04
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: G09C1/00,G06F7/72
Applicant(s) Name: Fujitsu Ltd. Address:
Inventor(s) Name: Itoh Kouichi
Attorney & Agent: li hui
Abstract:
     A computation method for use in cryptography which employs the Montgomery modular multiplication algorithm. To speed up the computation process, an equivalence which gives the same remainder value as a divisor n is computed as a value relating to a Montgomery conversion parameter used in a Montgomery multiplication remainder operation. That is, the method calculates an equivalence H 0 = 2 m*k 1 (mod n) relating to a divisor n of 2 m*k 1 (step A), computes an equivalence H = 2 E(p, m, k) (mod n) of 2 E(p, m, k) (mod n) from H 0 by an REDC operation (step B), and performs a correction operation by H = REDC (H, G) n for g = 2 k*G/p, m, k ) when 2 P > mxk (step C).
Time: 8