109 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			109 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
/* Copyright 2016 Brian Smith.
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 *
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 * Permission to use, copy, modify, and/or distribute this software for any
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 * purpose with or without fee is hereby granted, provided that the above
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 * copyright notice and this permission notice appear in all copies.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
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 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
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 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#include "ecp_nistz256.h"
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#include "../../limbs/limbs.h"
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#include "../../internal.h"
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#include "../bn/internal.h"
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#include "../../limbs/limbs.inl"
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typedef Limb Elem[P256_LIMBS];
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typedef Limb ScalarMont[P256_LIMBS];
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typedef Limb Scalar[P256_LIMBS];
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void GFp_p256_scalar_sqr_rep_mont(ScalarMont r, const ScalarMont a, Limb rep);
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#if defined(OPENSSL_ARM) || defined(OPENSSL_X86)
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void GFp_nistz256_sqr_mont(Elem r, const Elem a) {
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  /* XXX: Inefficient. TODO: optimize with dedicated squaring routine. */
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  GFp_nistz256_mul_mont(r, a, a);
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}
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#endif
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#if !defined(OPENSSL_X86_64)
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void GFp_p256_scalar_mul_mont(ScalarMont r, const ScalarMont a,
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                              const ScalarMont b) {
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  static const BN_ULONG N[] = {
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    TOBN(0xf3b9cac2, 0xfc632551),
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    TOBN(0xbce6faad, 0xa7179e84),
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    TOBN(0xffffffff, 0xffffffff),
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    TOBN(0xffffffff, 0x00000000),
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  };
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  static const BN_ULONG N_N0[] = {
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    BN_MONT_CTX_N0(0xccd1c8aa, 0xee00bc4f)
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  };
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  /* XXX: Inefficient. TODO: optimize with dedicated multiplication routine. */
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  GFp_bn_mul_mont(r, a, b, N, N_N0, P256_LIMBS);
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}
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#endif
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#if defined(OPENSSL_X86_64)
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void GFp_p256_scalar_sqr_mont(ScalarMont r, const ScalarMont a) {
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  GFp_p256_scalar_sqr_rep_mont(r, a, 1);
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}
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#else
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void GFp_p256_scalar_sqr_mont(ScalarMont r, const ScalarMont a) {
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  GFp_p256_scalar_mul_mont(r, a, a);
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}
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void GFp_p256_scalar_sqr_rep_mont(ScalarMont r, const ScalarMont a, Limb rep) {
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  dev_assert_secret(rep >= 1);
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  GFp_p256_scalar_sqr_mont(r, a);
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  for (Limb i = 1; i < rep; ++i) {
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    GFp_p256_scalar_sqr_mont(r, r);
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  }
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}
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#endif
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#if !defined(OPENSSL_X86_64)
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/* TODO(perf): Optimize these. */
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void GFp_nistz256_select_w5(P256_POINT *out, const P256_POINT table[16],
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                            crypto_word index) {
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  dev_assert_secret(index >= 0);
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  alignas(32) Elem x; limbs_zero(x, P256_LIMBS);
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  alignas(32) Elem y; limbs_zero(y, P256_LIMBS);
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  alignas(32) Elem z; limbs_zero(z, P256_LIMBS);
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  // TODO: Rewrite in terms of |limbs_select|.
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  for (size_t i = 0; i < 16; ++i) {
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    crypto_word equal = constant_time_eq_w(index, (crypto_word)i + 1);
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    for (size_t j = 0; j < P256_LIMBS; ++j) {
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      x[j] = constant_time_select_w(equal, table[i].X[j], x[j]);
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      y[j] = constant_time_select_w(equal, table[i].Y[j], y[j]);
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      z[j] = constant_time_select_w(equal, table[i].Z[j], z[j]);
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    }
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  }
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  limbs_copy(out->X, x, P256_LIMBS);
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  limbs_copy(out->Y, y, P256_LIMBS);
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  limbs_copy(out->Z, z, P256_LIMBS);
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}
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#if defined GFp_USE_LARGE_TABLE
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void GFp_nistz256_select_w7(P256_POINT_AFFINE *out,
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                            const PRECOMP256_ROW table, crypto_word index) {
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  alignas(32) Limb xy[P256_LIMBS * 2];
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  limbs_select(xy, table, P256_LIMBS * 2, 64, index - 1);
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  limbs_copy(out->X, &xy[0], P256_LIMBS);
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  limbs_copy(out->Y, &xy[P256_LIMBS], P256_LIMBS);
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}
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#endif
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#endif
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