In this paper we propose a new
addition formula in projective coordinates for elliptic curves over GF(2n).
The new formula speeds up the elliptic curve scalar multiplication by reducing
the number of field multiplications. This was achieved by rewriting the
elliptic curve addition formula. The complexity analysis shows that the new
addition formula speeds up the addition in projective coordinates by about 10
-12 percent, which leads to enhanced
scalar multiplication methods for random and Koblitz curves.