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Diffstat (limited to '')
-rw-r--r-- | security/nss/lib/freebl/ecl/ecp_jm.c | 297 |
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; +} |