Patent ID: 6782100
Filing Date: 2004-08-24
Classification: G06F,H04L

Abstract:
A method of computing a public key kP in an elliptic curve cryptosystem, said method comprising:a) utilising the x coordinate of a seed point P to perform successive double and add operations on P to obtain the values of the x coordinates of (kâˆ’1)P and kP; b) determining at least one point on the elliptic curve corresponding to one of the possible values of (kâˆ’1)P by deriving a possible value of the y coordinate of (kâˆ’1)P from the x coordinate of (kâˆ’1)P; c) determining at least one point on the elliptic curve corresponding to one of the possible values of kP by deriving a possible value of the y coordinate of kP from the x coordinate of kP; d) selecting as the value of kP the one of the possible points corresponding to kP that differs by P from one of the possible points corresponding to (kâˆ’1)P to form the public key kP.