1. A method for multiplying an elliptic curve point Q(x,y) by a scalar to provide a point kQ, the method comprising the steps of: a) selecting an elliptic curve over a finite field F such that there exists an endomorphism ψ where ψ(Q)=λ.Q for all points Q(x,y) on the elliptic curve, and λ is an integer, b) establishing a representation of said scalar k as a combination of components k i and said integer λ c) combining said representation and said point Q to form a composite representation of a multiple corresponding to kQ and d) computing a value corresponding to said point kQ from said composite representation of kQ.