--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nss/lib/freebl/ecl/ecp_jm.c	Mon Jul 28 10:47:06 2014 +0200
@@ -0,0 +1,289 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ecp.h"
+#include "ecl-priv.h"
+#include "mplogic.h"
+#include <stdlib.h>
+
+#define MAX_SCRATCH 6
+
+/* Computes R = 2P.  Elliptic curve points P and R can be identical.  Uses 
+ * Modified Jacobian coordinates.
+ *
+ * Assumes input is already field-encoded using field_enc, and returns 
+ * output that is still field-encoded.
+ *
+ */
+mp_err
+ec_GFp_pt_dbl_jm(const mp_int *px, const mp_int *py, const mp_int *pz,
+				 const mp_int *paz4, mp_int *rx, mp_int *ry, mp_int *rz,
+				 mp_int *raz4, mp_int scratch[], const ECGroup *group)
+{
+	mp_err res = MP_OKAY;
+	mp_int *t0, *t1, *M, *S;
+
+	t0 = &scratch[0];
+	t1 = &scratch[1];
+	M = &scratch[2];
+	S = &scratch[3];
+
+#if MAX_SCRATCH < 4
+#error "Scratch array defined too small "
+#endif
+
+	/* Check for point at infinity */
+	if (ec_GFp_pt_is_inf_jac(px, py, pz) == MP_YES) {
+		/* Set r = pt at infinity by setting rz = 0 */
+
+		MP_CHECKOK(ec_GFp_pt_set_inf_jac(rx, ry, rz));
+		goto CLEANUP;
+	}
+
+	/* M = 3 (px^2) + a*(pz^4) */
+	MP_CHECKOK(group->meth->field_sqr(px, t0, group->meth));
+	MP_CHECKOK(group->meth->field_add(t0, t0, M, group->meth));
+	MP_CHECKOK(group->meth->field_add(t0, M, t0, group->meth));
+	MP_CHECKOK(group->meth->field_add(t0, paz4, M, group->meth));
+
+	/* rz = 2 * py * pz */
+	MP_CHECKOK(group->meth->field_mul(py, pz, S, group->meth));
+	MP_CHECKOK(group->meth->field_add(S, S, rz, group->meth));
+
+	/* t0 = 2y^2 , t1 = 8y^4 */
+	MP_CHECKOK(group->meth->field_sqr(py, t0, group->meth));
+	MP_CHECKOK(group->meth->field_add(t0, t0, t0, group->meth));
+	MP_CHECKOK(group->meth->field_sqr(t0, t1, group->meth));
+	MP_CHECKOK(group->meth->field_add(t1, t1, t1, group->meth));
+
+	/* S = 4 * px * py^2 = 2 * px * t0 */
+	MP_CHECKOK(group->meth->field_mul(px, t0, S, group->meth));
+	MP_CHECKOK(group->meth->field_add(S, S, S, group->meth));
+
+
+	/* rx = M^2 - 2S */
+	MP_CHECKOK(group->meth->field_sqr(M, rx, group->meth));
+	MP_CHECKOK(group->meth->field_sub(rx, S, rx, group->meth));
+	MP_CHECKOK(group->meth->field_sub(rx, S, rx, group->meth));
+
+	/* ry = M * (S - rx) - t1 */
+	MP_CHECKOK(group->meth->field_sub(S, rx, S, group->meth));
+	MP_CHECKOK(group->meth->field_mul(S, M, ry, group->meth));
+	MP_CHECKOK(group->meth->field_sub(ry, t1, ry, group->meth));
+
+	/* ra*z^4 = 2*t1*(apz4) */
+	MP_CHECKOK(group->meth->field_mul(paz4, t1, raz4, group->meth));
+	MP_CHECKOK(group->meth->field_add(raz4, raz4, raz4, group->meth));
+
+
+  CLEANUP:
+	return res;
+}
+
+/* Computes R = P + Q where R is (rx, ry, rz), P is (px, py, pz) and Q is
+ * (qx, qy, 1).  Elliptic curve points P, Q, and R can all be identical.
+ * Uses mixed Modified_Jacobian-affine coordinates. Assumes input is
+ * already field-encoded using field_enc, and returns output that is still
+ * field-encoded. */
+mp_err
+ec_GFp_pt_add_jm_aff(const mp_int *px, const mp_int *py, const mp_int *pz,
+					 const mp_int *paz4, const mp_int *qx,
+					 const mp_int *qy, mp_int *rx, mp_int *ry, mp_int *rz,
+					 mp_int *raz4, mp_int scratch[], const ECGroup *group)
+{
+	mp_err res = MP_OKAY;
+	mp_int *A, *B, *C, *D, *C2, *C3;
+
+	A = &scratch[0];
+	B = &scratch[1];
+	C = &scratch[2];
+	D = &scratch[3];
+	C2 = &scratch[4];
+	C3 = &scratch[5];
+
+#if MAX_SCRATCH < 6
+#error "Scratch array defined too small "
+#endif
+
+	/* If either P or Q is the point at infinity, then return the other
+	 * point */
+	if (ec_GFp_pt_is_inf_jac(px, py, pz) == MP_YES) {
+		MP_CHECKOK(ec_GFp_pt_aff2jac(qx, qy, rx, ry, rz, group));
+		MP_CHECKOK(group->meth->field_sqr(rz, raz4, group->meth));
+		MP_CHECKOK(group->meth->field_sqr(raz4, raz4, group->meth));
+		MP_CHECKOK(group->meth->
+				   field_mul(raz4, &group->curvea, raz4, group->meth));
+		goto CLEANUP;
+	}
+	if (ec_GFp_pt_is_inf_aff(qx, qy) == MP_YES) {
+		MP_CHECKOK(mp_copy(px, rx));
+		MP_CHECKOK(mp_copy(py, ry));
+		MP_CHECKOK(mp_copy(pz, rz));
+		MP_CHECKOK(mp_copy(paz4, raz4));
+		goto CLEANUP;
+	}
+
+	/* A = qx * pz^2, B = qy * pz^3 */
+	MP_CHECKOK(group->meth->field_sqr(pz, A, group->meth));
+	MP_CHECKOK(group->meth->field_mul(A, pz, B, group->meth));
+	MP_CHECKOK(group->meth->field_mul(A, qx, A, group->meth));
+	MP_CHECKOK(group->meth->field_mul(B, qy, B, group->meth));
+
+	/* C = A - px, D = B - py */
+	MP_CHECKOK(group->meth->field_sub(A, px, C, group->meth));
+	MP_CHECKOK(group->meth->field_sub(B, py, D, group->meth));
+
+	/* C2 = C^2, C3 = C^3 */
+	MP_CHECKOK(group->meth->field_sqr(C, C2, group->meth));
+	MP_CHECKOK(group->meth->field_mul(C, C2, C3, group->meth));
+
+	/* rz = pz * C */
+	MP_CHECKOK(group->meth->field_mul(pz, C, rz, group->meth));
+
+	/* C = px * C^2 */
+	MP_CHECKOK(group->meth->field_mul(px, C2, C, group->meth));
+	/* A = D^2 */
+	MP_CHECKOK(group->meth->field_sqr(D, A, group->meth));
+
+	/* rx = D^2 - (C^3 + 2 * (px * C^2)) */
+	MP_CHECKOK(group->meth->field_add(C, C, rx, group->meth));
+	MP_CHECKOK(group->meth->field_add(C3, rx, rx, group->meth));
+	MP_CHECKOK(group->meth->field_sub(A, rx, rx, group->meth));
+
+	/* C3 = py * C^3 */
+	MP_CHECKOK(group->meth->field_mul(py, C3, C3, group->meth));
+
+	/* ry = D * (px * C^2 - rx) - py * C^3 */
+	MP_CHECKOK(group->meth->field_sub(C, rx, ry, group->meth));
+	MP_CHECKOK(group->meth->field_mul(D, ry, ry, group->meth));
+	MP_CHECKOK(group->meth->field_sub(ry, C3, ry, group->meth));
+
+	/* raz4 = a * rz^4 */
+	MP_CHECKOK(group->meth->field_sqr(rz, raz4, group->meth));
+	MP_CHECKOK(group->meth->field_sqr(raz4, raz4, group->meth));
+	MP_CHECKOK(group->meth->
+			   field_mul(raz4, &group->curvea, raz4, group->meth));
+CLEANUP:
+	return res;
+}
+
+/* Computes R = nP where R is (rx, ry) and P is the base point. Elliptic
+ * curve points P and R can be identical. Uses mixed Modified-Jacobian
+ * co-ordinates for doubling and Chudnovsky Jacobian coordinates for
+ * additions. Assumes input is already field-encoded using field_enc, and
+ * returns output that is still field-encoded. Uses 5-bit window NAF
+ * method (algorithm 11) for scalar-point multiplication from Brown,
+ * Hankerson, Lopez, Menezes. Software Implementation of the NIST Elliptic 
+ * Curves Over Prime Fields. */
+mp_err
+ec_GFp_pt_mul_jm_wNAF(const mp_int *n, const mp_int *px, const mp_int *py,
+					  mp_int *rx, mp_int *ry, const ECGroup *group)
+{
+	mp_err res = MP_OKAY;
+	mp_int precomp[16][2], rz, tpx, tpy;
+	mp_int raz4;
+	mp_int scratch[MAX_SCRATCH];
+	signed char *naf = NULL;
+	int i, orderBitSize;
+
+	MP_DIGITS(&rz) = 0;
+	MP_DIGITS(&raz4) = 0;
+	MP_DIGITS(&tpx) = 0;
+	MP_DIGITS(&tpy) = 0;
+	for (i = 0; i < 16; i++) {
+		MP_DIGITS(&precomp[i][0]) = 0;
+		MP_DIGITS(&precomp[i][1]) = 0;
+	}
+	for (i = 0; i < MAX_SCRATCH; i++) {
+		MP_DIGITS(&scratch[i]) = 0;
+	}
+
+	ARGCHK(group != NULL, MP_BADARG);
+	ARGCHK((n != NULL) && (px != NULL) && (py != NULL), MP_BADARG);
+
+	/* initialize precomputation table */
+	MP_CHECKOK(mp_init(&tpx));
+	MP_CHECKOK(mp_init(&tpy));;
+	MP_CHECKOK(mp_init(&rz));
+	MP_CHECKOK(mp_init(&raz4));
+
+	for (i = 0; i < 16; i++) {
+		MP_CHECKOK(mp_init(&precomp[i][0]));
+		MP_CHECKOK(mp_init(&precomp[i][1]));
+	}
+	for (i = 0; i < MAX_SCRATCH; i++) {
+		MP_CHECKOK(mp_init(&scratch[i]));
+	}
+
+	/* Set out[8] = P */
+	MP_CHECKOK(mp_copy(px, &precomp[8][0]));
+	MP_CHECKOK(mp_copy(py, &precomp[8][1]));
+
+	/* Set (tpx, tpy) = 2P */
+	MP_CHECKOK(group->
+			   point_dbl(&precomp[8][0], &precomp[8][1], &tpx, &tpy,
+						 group));
+
+	/* Set 3P, 5P, ..., 15P */
+	for (i = 8; i < 15; i++) {
+		MP_CHECKOK(group->
+				   point_add(&precomp[i][0], &precomp[i][1], &tpx, &tpy,
+							 &precomp[i + 1][0], &precomp[i + 1][1],
+							 group));
+	}
+
+	/* Set -15P, -13P, ..., -P */
+	for (i = 0; i < 8; i++) {
+		MP_CHECKOK(mp_copy(&precomp[15 - i][0], &precomp[i][0]));
+		MP_CHECKOK(group->meth->
+				   field_neg(&precomp[15 - i][1], &precomp[i][1],
+							 group->meth));
+	}
+
+	/* R = inf */
+	MP_CHECKOK(ec_GFp_pt_set_inf_jac(rx, ry, &rz));
+
+	orderBitSize = mpl_significant_bits(&group->order);
+
+	/* Allocate memory for NAF */
+	naf = (signed char *) malloc(sizeof(signed char) * (orderBitSize + 1));
+	if (naf == NULL) {
+		res = MP_MEM;
+		goto CLEANUP;
+	}
+
+	/* Compute 5NAF */
+	ec_compute_wNAF(naf, orderBitSize, n, 5);
+
+	/* wNAF method */
+	for (i = orderBitSize; i >= 0; i--) {
+		/* R = 2R */
+		ec_GFp_pt_dbl_jm(rx, ry, &rz, &raz4, rx, ry, &rz, 
+					     &raz4, scratch, group);
+		if (naf[i] != 0) {
+			ec_GFp_pt_add_jm_aff(rx, ry, &rz, &raz4,
+								 &precomp[(naf[i] + 15) / 2][0],
+								 &precomp[(naf[i] + 15) / 2][1], rx, ry,
+								 &rz, &raz4, scratch, group);
+		}
+	}
+
+	/* convert result S to affine coordinates */
+	MP_CHECKOK(ec_GFp_pt_jac2aff(rx, ry, &rz, rx, ry, group));
+
+  CLEANUP:
+	for (i = 0; i < MAX_SCRATCH; i++) {
+		mp_clear(&scratch[i]);
+	}
+	for (i = 0; i < 16; i++) {
+		mp_clear(&precomp[i][0]);
+		mp_clear(&precomp[i][1]);
+	}
+	mp_clear(&tpx);
+	mp_clear(&tpy);
+	mp_clear(&rz);
+	mp_clear(&raz4);
+	free(naf);
+	return res;
+}