/*
* Use is subject to license terms.
*
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/* *********************************************************************
*
* The Original Code is the elliptic curve math library for binary polynomial field curves.
*
* The Initial Developer of the Original Code is
* Sun Microsystems, Inc.
* Portions created by the Initial Developer are Copyright (C) 2003
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Sheueling Chang-Shantz <sheueling.chang@sun.com>,
* Stephen Fung <fungstep@hotmail.com>, and
* Douglas Stebila <douglas@stebila.ca>, Sun Microsystems Laboratories.
*
*********************************************************************** */
#include "ec2.h"
#include "mplogic.h"
#include "mp_gf2m.h"
#ifndef _KERNEL
#include <stdlib.h>
#endif
/* Compute the x-coordinate x/z for the point 2*(x/z) in Montgomery
* projective coordinates. Uses algorithm Mdouble in appendix of Lopez, J.
* and Dahab, R. "Fast multiplication on elliptic curves over GF(2^m)
* without precomputation". modified to not require precomputation of
* c=b^{2^{m-1}}. */
static mp_err
{
return res;
}
* Montgomery projective coordinates. Uses algorithm Madd in appendix of
* Lopex, J. and Dahab, R. "Fast multiplication on elliptic curves over
* GF(2^m) without precomputation". */
static mp_err
{
return res;
}
/* Compute the x, y affine coordinates from the point (x1, z1) (x2, z2)
* using Montgomery point multiplication algorithm Mxy() in appendix of
* Lopex, J. and Dahab, R. "Fast multiplication on elliptic curves over
* GF(2^m) without precomputation". Returns: 0 on error 1 if return value
* should be the point at infinity 2 otherwise */
static int
{
int ret = 0;
ret = 1;
goto CLEANUP;
}
ret = 2;
goto CLEANUP;
}
}
ret = 2;
return ret;
} else {
return 0;
}
}
/* Computes R = nP based on algorithm 2P of Lopex, J. and Dahab, R. "Fast
* multiplication on elliptic curves over GF(2^m) without
* precomputation". Elliptic curve points P and R can be identical. Uses
* Montgomery projective coordinates. */
{
int i, j;
/* if result should be point at infinity */
goto CLEANUP;
}
* x1^2 =
* px^2 */
* =
* px^4
* +
* b
*/
/* find top-most bit and go one past it */
i = MP_USED(n) - 1;
j = MP_DIGIT_BIT - 1;
top_bit = 1;
mask >>= 1;
j--;
}
mask >>= 1;
j--;
/* if top most bit was at word break, go to next word */
if (!mask) {
i--;
j = MP_DIGIT_BIT - 1;
}
for (; i >= 0; i--) {
for (; j >= 0; j--) {
} else {
}
mask >>= 1;
}
j = MP_DIGIT_BIT - 1;
}
/* convert out of "projective" coordinates */
if (i == 0) {
goto CLEANUP;
} else if (i == 1) {
} else {
}
return res;
}