Method of privacy communication using elliptic curves

Patent 5351297 Issued on September 27, 1994. Estimated Expiration Date:

April 16, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

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Inventors

Assignee

Matsushita Electric Industrial Co., Ltd.

Application

No. 048478 filed on 04/16/1993

US Classes:

380/28, PARTICULAR ALGORITHMIC FUNCTION ENCODING380/30Public key

Examiners

Primary: Cain, David

Attorney, Agent or Firm

Price, Gess & Ubell

Foreign Patent References

59-107658 JP. 06/12/1984
63-52536 JP. 03/12/1988
1119144 JP. 05/12/1989
3505033 JP. 10/12/1991

International Class

H04K 001/00

Foreign Application Priority Data

1991-06-28 JP

Abstract

The present invention provides a method of privacy communication, in which an elliptic curve E and an element thereof are notified to all parties who wish to communicate, and data are transmitted from one party to another by using a calculation of the element and coded data made in secret by each party. The method is characterized by a construction of E(GF(p)) such whose number of elements has exactly p, assuming that p is a prime number and E(GF(p)) is a group of elements of GF(p) on the elliptic curve E. More particularly, E(GF(p)) is constructed by an algorithm: let d be a positive integer such that gives an imaginary quadratic field Q((-d1/2)) with a small class number; then find a prime number p such that 4⋅p-1=d⋅square number; and find a solution of a class polynomial Hd (x)=0 modulo p such that is defined by d and given with a j-invariant.