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-rw-r--r--security/nss/lib/freebl/ecl/ecp_jm.c297
1 files changed, 297 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/ecl/ecp_jm.c b/security/nss/lib/freebl/ecl/ecp_jm.c
new file mode 100644
index 0000000000..7998421713
--- /dev/null
+++ b/security/nss/lib/freebl/ecl/ecp_jm.c
@@ -0,0 +1,297 @@
+/* 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.
+ *
+ */
+static 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. */
+static 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));
+
+ /* Check P == Q */
+ if (mp_cmp(A, px) == 0) {
+ if (mp_cmp(B, py) == 0) {
+ /* If Px == Qx && Py == Qy, double P. */
+ return ec_GFp_pt_dbl_jm(px, py, pz, paz4, rx, ry, rz, raz4,
+ scratch, group);
+ }
+ /* If Px == Qx && Py != Qy, return point at infinity. */
+ return ec_GFp_pt_set_inf_jac(rx, ry, rz);
+ }
+
+ /* 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 = 0;
+
+ 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);
+ if (naf) {
+ memset(naf, 0, orderBitSize + 1);
+ }
+ free(naf);
+ return res;
+}
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