blob: ab9b9fbd507981d8a4e9f69e704c1ea5aaa51974 [file] [log] [blame]
/* Copyright 2016 Brian Smith.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include "ecp_nistz256.h"
#include "../../limbs/limbs.h"
#include "../../internal.h"
#include "../bn/internal.h"
#include "../../limbs/limbs.inl"
typedef Limb Elem[P256_LIMBS];
typedef Limb ScalarMont[P256_LIMBS];
typedef Limb Scalar[P256_LIMBS];
/* Prototypes to avoid -Wmissing-prototypes warnings. */
void GFp_p256_scalar_mul_mont(ScalarMont r, const ScalarMont a,
const ScalarMont b);
void GFp_p256_scalar_sqr_mont(ScalarMont r, const ScalarMont a);
void GFp_p256_scalar_sqr_rep_mont(ScalarMont r, const ScalarMont a, int rep);
#if defined(OPENSSL_ARM) || defined(OPENSSL_X86)
void GFp_nistz256_sqr_mont(Elem r, const Elem a) {
/* XXX: Inefficient. TODO: optimize with dedicated squaring routine. */
GFp_nistz256_mul_mont(r, a, a);
}
#endif
#if !defined(OPENSSL_X86_64)
void GFp_p256_scalar_mul_mont(ScalarMont r, const ScalarMont a,
const ScalarMont b) {
static const BN_ULONG N[] = {
TOBN(0xf3b9cac2, 0xfc632551),
TOBN(0xbce6faad, 0xa7179e84),
TOBN(0xffffffff, 0xffffffff),
TOBN(0xffffffff, 0x00000000),
};
static const BN_ULONG N_N0[] = {
BN_MONT_CTX_N0(0xccd1c8aa, 0xee00bc4f)
};
/* XXX: Inefficient. TODO: optimize with dedicated multiplication routine. */
GFp_bn_mul_mont(r, a, b, N, N_N0, P256_LIMBS);
}
#endif
#if defined(OPENSSL_X86_64)
void GFp_p256_scalar_sqr_mont(ScalarMont r, const ScalarMont a) {
GFp_p256_scalar_sqr_rep_mont(r, a, 1);
}
#else
void GFp_p256_scalar_sqr_mont(ScalarMont r, const ScalarMont a) {
GFp_p256_scalar_mul_mont(r, a, a);
}
void GFp_p256_scalar_sqr_rep_mont(ScalarMont r, const ScalarMont a, int rep) {
assert(rep >= 1);
GFp_p256_scalar_sqr_mont(r, a);
for (int i = 1; i < rep; ++i) {
GFp_p256_scalar_sqr_mont(r, r);
}
}
#endif
#if !defined(OPENSSL_X86_64)
#include <string.h>
/* TODO(perf): Optimize these. */
void GFp_nistz256_select_w5(P256_POINT *out, const P256_POINT table[16],
int index) {
assert(index >= 0);
size_t index_s = (size_t)index; /* XXX: constant time? */
alignas(32) Elem x; memset(x, 0, sizeof(x));
alignas(32) Elem y; memset(y, 0, sizeof(y));
alignas(32) Elem z; memset(z, 0, sizeof(z));
for (size_t i = 0; i < 16; ++i) {
Limb mask = constant_time_eq_w(index_s, i + 1);
for (size_t j = 0; j < P256_LIMBS; ++j) {
x[j] |= table[i].X[j] & mask;
y[j] |= table[i].Y[j] & mask;
z[j] |= table[i].Z[j] & mask;
}
}
limbs_copy(out->X, x, P256_LIMBS);
limbs_copy(out->Y, y, P256_LIMBS);
limbs_copy(out->Z, z, P256_LIMBS);
}
void GFp_nistz256_select_w7(P256_POINT_AFFINE *out,
const P256_POINT_AFFINE table[64], int index) {
assert(index >= 0);
size_t index_as_s = (size_t)index; /* XXX: constant time? */
alignas(32) Elem x; memset(x, 0, sizeof(x));
alignas(32) Elem y; memset(y, 0, sizeof(y));
for (size_t i = 0; i < 64; ++i) {
Limb mask = constant_time_eq_w(index_as_s, i + 1);
for (size_t j = 0; j < P256_LIMBS; ++j) {
x[j] |= table[i].X[j] & mask;
y[j] |= table[i].Y[j] & mask;
}
}
limbs_copy(out->X, x, P256_LIMBS);
limbs_copy(out->Y, y, P256_LIMBS);
}
#endif