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-rw-r--r--security/nss/lib/freebl/ecl/ecp_aff.c308
1 files changed, 308 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/ecl/ecp_aff.c b/security/nss/lib/freebl/ecl/ecp_aff.c
new file mode 100644
index 000000000..47fb27326
--- /dev/null
+++ b/security/nss/lib/freebl/ecl/ecp_aff.c
@@ -0,0 +1,308 @@
+/* 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 "mplogic.h"
+#include <stdlib.h>
+
+/* Checks if point P(px, py) is at infinity. Uses affine coordinates. */
+mp_err
+ec_GFp_pt_is_inf_aff(const mp_int *px, const mp_int *py)
+{
+
+ if ((mp_cmp_z(px) == 0) && (mp_cmp_z(py) == 0)) {
+ return MP_YES;
+ } else {
+ return MP_NO;
+ }
+}
+
+/* Sets P(px, py) to be the point at infinity. Uses affine coordinates. */
+mp_err
+ec_GFp_pt_set_inf_aff(mp_int *px, mp_int *py)
+{
+ mp_zero(px);
+ mp_zero(py);
+ return MP_OKAY;
+}
+
+/* Computes R = P + Q based on IEEE P1363 A.10.1. Elliptic curve points P,
+ * Q, and R can all be identical. Uses 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_aff(const mp_int *px, const mp_int *py, const mp_int *qx,
+ const mp_int *qy, mp_int *rx, mp_int *ry,
+ const ECGroup *group)
+{
+ mp_err res = MP_OKAY;
+ mp_int lambda, temp, tempx, tempy;
+
+ MP_DIGITS(&lambda) = 0;
+ MP_DIGITS(&temp) = 0;
+ MP_DIGITS(&tempx) = 0;
+ MP_DIGITS(&tempy) = 0;
+ MP_CHECKOK(mp_init(&lambda));
+ MP_CHECKOK(mp_init(&temp));
+ MP_CHECKOK(mp_init(&tempx));
+ MP_CHECKOK(mp_init(&tempy));
+ /* if P = inf, then R = Q */
+ if (ec_GFp_pt_is_inf_aff(px, py) == 0) {
+ MP_CHECKOK(mp_copy(qx, rx));
+ MP_CHECKOK(mp_copy(qy, ry));
+ res = MP_OKAY;
+ goto CLEANUP;
+ }
+ /* if Q = inf, then R = P */
+ if (ec_GFp_pt_is_inf_aff(qx, qy) == 0) {
+ MP_CHECKOK(mp_copy(px, rx));
+ MP_CHECKOK(mp_copy(py, ry));
+ res = MP_OKAY;
+ goto CLEANUP;
+ }
+ /* if px != qx, then lambda = (py-qy) / (px-qx) */
+ if (mp_cmp(px, qx) != 0) {
+ MP_CHECKOK(group->meth->field_sub(py, qy, &tempy, group->meth));
+ MP_CHECKOK(group->meth->field_sub(px, qx, &tempx, group->meth));
+ MP_CHECKOK(group->meth->field_div(&tempy, &tempx, &lambda, group->meth));
+ } else {
+ /* if py != qy or qy = 0, then R = inf */
+ if (((mp_cmp(py, qy) != 0)) || (mp_cmp_z(qy) == 0)) {
+ mp_zero(rx);
+ mp_zero(ry);
+ res = MP_OKAY;
+ goto CLEANUP;
+ }
+ /* lambda = (3qx^2+a) / (2qy) */
+ MP_CHECKOK(group->meth->field_sqr(qx, &tempx, group->meth));
+ MP_CHECKOK(mp_set_int(&temp, 3));
+ if (group->meth->field_enc) {
+ MP_CHECKOK(group->meth->field_enc(&temp, &temp, group->meth));
+ }
+ MP_CHECKOK(group->meth->field_mul(&tempx, &temp, &tempx, group->meth));
+ MP_CHECKOK(group->meth->field_add(&tempx, &group->curvea, &tempx, group->meth));
+ MP_CHECKOK(mp_set_int(&temp, 2));
+ if (group->meth->field_enc) {
+ MP_CHECKOK(group->meth->field_enc(&temp, &temp, group->meth));
+ }
+ MP_CHECKOK(group->meth->field_mul(qy, &temp, &tempy, group->meth));
+ MP_CHECKOK(group->meth->field_div(&tempx, &tempy, &lambda, group->meth));
+ }
+ /* rx = lambda^2 - px - qx */
+ MP_CHECKOK(group->meth->field_sqr(&lambda, &tempx, group->meth));
+ MP_CHECKOK(group->meth->field_sub(&tempx, px, &tempx, group->meth));
+ MP_CHECKOK(group->meth->field_sub(&tempx, qx, &tempx, group->meth));
+ /* ry = (x1-x2) * lambda - y1 */
+ MP_CHECKOK(group->meth->field_sub(qx, &tempx, &tempy, group->meth));
+ MP_CHECKOK(group->meth->field_mul(&tempy, &lambda, &tempy, group->meth));
+ MP_CHECKOK(group->meth->field_sub(&tempy, qy, &tempy, group->meth));
+ MP_CHECKOK(mp_copy(&tempx, rx));
+ MP_CHECKOK(mp_copy(&tempy, ry));
+
+CLEANUP:
+ mp_clear(&lambda);
+ mp_clear(&temp);
+ mp_clear(&tempx);
+ mp_clear(&tempy);
+ return res;
+}
+
+/* Computes R = P - Q. Elliptic curve points P, Q, and R can all be
+ * identical. Uses affine coordinates. Assumes input is already
+ * field-encoded using field_enc, and returns output that is still
+ * field-encoded. */
+mp_err
+ec_GFp_pt_sub_aff(const mp_int *px, const mp_int *py, const mp_int *qx,
+ const mp_int *qy, mp_int *rx, mp_int *ry,
+ const ECGroup *group)
+{
+ mp_err res = MP_OKAY;
+ mp_int nqy;
+
+ MP_DIGITS(&nqy) = 0;
+ MP_CHECKOK(mp_init(&nqy));
+ /* nqy = -qy */
+ MP_CHECKOK(group->meth->field_neg(qy, &nqy, group->meth));
+ res = group->point_add(px, py, qx, &nqy, rx, ry, group);
+CLEANUP:
+ mp_clear(&nqy);
+ return res;
+}
+
+/* Computes R = 2P. Elliptic curve points P and R can be identical. Uses
+ * affine coordinates. Assumes input is already field-encoded using
+ * field_enc, and returns output that is still field-encoded. */
+mp_err
+ec_GFp_pt_dbl_aff(const mp_int *px, const mp_int *py, mp_int *rx,
+ mp_int *ry, const ECGroup *group)
+{
+ return ec_GFp_pt_add_aff(px, py, px, py, rx, ry, group);
+}
+
+/* by default, this routine is unused and thus doesn't need to be compiled */
+#ifdef ECL_ENABLE_GFP_PT_MUL_AFF
+/* Computes R = nP based on IEEE P1363 A.10.3. Elliptic curve points P and
+ * R can be identical. Uses affine coordinates. Assumes input is already
+ * field-encoded using field_enc, and returns output that is still
+ * field-encoded. */
+mp_err
+ec_GFp_pt_mul_aff(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 k, k3, qx, qy, sx, sy;
+ int b1, b3, i, l;
+
+ MP_DIGITS(&k) = 0;
+ MP_DIGITS(&k3) = 0;
+ MP_DIGITS(&qx) = 0;
+ MP_DIGITS(&qy) = 0;
+ MP_DIGITS(&sx) = 0;
+ MP_DIGITS(&sy) = 0;
+ MP_CHECKOK(mp_init(&k));
+ MP_CHECKOK(mp_init(&k3));
+ MP_CHECKOK(mp_init(&qx));
+ MP_CHECKOK(mp_init(&qy));
+ MP_CHECKOK(mp_init(&sx));
+ MP_CHECKOK(mp_init(&sy));
+
+ /* if n = 0 then r = inf */
+ if (mp_cmp_z(n) == 0) {
+ mp_zero(rx);
+ mp_zero(ry);
+ res = MP_OKAY;
+ goto CLEANUP;
+ }
+ /* Q = P, k = n */
+ MP_CHECKOK(mp_copy(px, &qx));
+ MP_CHECKOK(mp_copy(py, &qy));
+ MP_CHECKOK(mp_copy(n, &k));
+ /* if n < 0 then Q = -Q, k = -k */
+ if (mp_cmp_z(n) < 0) {
+ MP_CHECKOK(group->meth->field_neg(&qy, &qy, group->meth));
+ MP_CHECKOK(mp_neg(&k, &k));
+ }
+#ifdef ECL_DEBUG /* basic double and add method */
+ l = mpl_significant_bits(&k) - 1;
+ MP_CHECKOK(mp_copy(&qx, &sx));
+ MP_CHECKOK(mp_copy(&qy, &sy));
+ for (i = l - 1; i >= 0; i--) {
+ /* S = 2S */
+ MP_CHECKOK(group->point_dbl(&sx, &sy, &sx, &sy, group));
+ /* if k_i = 1, then S = S + Q */
+ if (mpl_get_bit(&k, i) != 0) {
+ MP_CHECKOK(group->point_add(&sx, &sy, &qx, &qy, &sx, &sy, group));
+ }
+ }
+#else /* double and add/subtract method from \
+ * standard */
+ /* k3 = 3 * k */
+ MP_CHECKOK(mp_set_int(&k3, 3));
+ MP_CHECKOK(mp_mul(&k, &k3, &k3));
+ /* S = Q */
+ MP_CHECKOK(mp_copy(&qx, &sx));
+ MP_CHECKOK(mp_copy(&qy, &sy));
+ /* l = index of high order bit in binary representation of 3*k */
+ l = mpl_significant_bits(&k3) - 1;
+ /* for i = l-1 downto 1 */
+ for (i = l - 1; i >= 1; i--) {
+ /* S = 2S */
+ MP_CHECKOK(group->point_dbl(&sx, &sy, &sx, &sy, group));
+ b3 = MP_GET_BIT(&k3, i);
+ b1 = MP_GET_BIT(&k, i);
+ /* if k3_i = 1 and k_i = 0, then S = S + Q */
+ if ((b3 == 1) && (b1 == 0)) {
+ MP_CHECKOK(group->point_add(&sx, &sy, &qx, &qy, &sx, &sy, group));
+ /* if k3_i = 0 and k_i = 1, then S = S - Q */
+ } else if ((b3 == 0) && (b1 == 1)) {
+ MP_CHECKOK(group->point_sub(&sx, &sy, &qx, &qy, &sx, &sy, group));
+ }
+ }
+#endif
+ /* output S */
+ MP_CHECKOK(mp_copy(&sx, rx));
+ MP_CHECKOK(mp_copy(&sy, ry));
+
+CLEANUP:
+ mp_clear(&k);
+ mp_clear(&k3);
+ mp_clear(&qx);
+ mp_clear(&qy);
+ mp_clear(&sx);
+ mp_clear(&sy);
+ return res;
+}
+#endif
+
+/* Validates a point on a GFp curve. */
+mp_err
+ec_GFp_validate_point(const mp_int *px, const mp_int *py, const ECGroup *group)
+{
+ mp_err res = MP_NO;
+ mp_int accl, accr, tmp, pxt, pyt;
+
+ MP_DIGITS(&accl) = 0;
+ MP_DIGITS(&accr) = 0;
+ MP_DIGITS(&tmp) = 0;
+ MP_DIGITS(&pxt) = 0;
+ MP_DIGITS(&pyt) = 0;
+ MP_CHECKOK(mp_init(&accl));
+ MP_CHECKOK(mp_init(&accr));
+ MP_CHECKOK(mp_init(&tmp));
+ MP_CHECKOK(mp_init(&pxt));
+ MP_CHECKOK(mp_init(&pyt));
+
+ /* 1: Verify that publicValue is not the point at infinity */
+ if (ec_GFp_pt_is_inf_aff(px, py) == MP_YES) {
+ res = MP_NO;
+ goto CLEANUP;
+ }
+ /* 2: Verify that the coordinates of publicValue are elements
+ * of the field.
+ */
+ if ((MP_SIGN(px) == MP_NEG) || (mp_cmp(px, &group->meth->irr) >= 0) ||
+ (MP_SIGN(py) == MP_NEG) || (mp_cmp(py, &group->meth->irr) >= 0)) {
+ res = MP_NO;
+ goto CLEANUP;
+ }
+ /* 3: Verify that publicValue is on the curve. */
+ if (group->meth->field_enc) {
+ group->meth->field_enc(px, &pxt, group->meth);
+ group->meth->field_enc(py, &pyt, group->meth);
+ } else {
+ MP_CHECKOK(mp_copy(px, &pxt));
+ MP_CHECKOK(mp_copy(py, &pyt));
+ }
+ /* left-hand side: y^2 */
+ MP_CHECKOK(group->meth->field_sqr(&pyt, &accl, group->meth));
+ /* right-hand side: x^3 + a*x + b = (x^2 + a)*x + b by Horner's rule */
+ MP_CHECKOK(group->meth->field_sqr(&pxt, &tmp, group->meth));
+ MP_CHECKOK(group->meth->field_add(&tmp, &group->curvea, &tmp, group->meth));
+ MP_CHECKOK(group->meth->field_mul(&tmp, &pxt, &accr, group->meth));
+ MP_CHECKOK(group->meth->field_add(&accr, &group->curveb, &accr, group->meth));
+ /* check LHS - RHS == 0 */
+ MP_CHECKOK(group->meth->field_sub(&accl, &accr, &accr, group->meth));
+ if (mp_cmp_z(&accr) != 0) {
+ res = MP_NO;
+ goto CLEANUP;
+ }
+ /* 4: Verify that the order of the curve times the publicValue
+ * is the point at infinity.
+ */
+ MP_CHECKOK(ECPoint_mul(group, &group->order, px, py, &pxt, &pyt));
+ if (ec_GFp_pt_is_inf_aff(&pxt, &pyt) != MP_YES) {
+ res = MP_NO;
+ goto CLEANUP;
+ }
+
+ res = MP_YES;
+
+CLEANUP:
+ mp_clear(&accl);
+ mp_clear(&accr);
+ mp_clear(&tmp);
+ mp_clear(&pxt);
+ mp_clear(&pyt);
+ return res;
+}