diff options
Diffstat (limited to 'openssl/crypto/ec/ecp_nistz256.c')
| -rwxr-xr-x | openssl/crypto/ec/ecp_nistz256.c | 1486 |
1 files changed, 1486 insertions, 0 deletions
diff --git a/openssl/crypto/ec/ecp_nistz256.c b/openssl/crypto/ec/ecp_nistz256.c new file mode 100755 index 000000000..2cd6599d8 --- /dev/null +++ b/openssl/crypto/ec/ecp_nistz256.c @@ -0,0 +1,1486 @@ +/****************************************************************************** + * * + * Copyright 2014 Intel Corporation * + * * + * Licensed under the Apache License, Version 2.0 (the "License"); * + * you may not use this file except in compliance with the License. * + * You may obtain a copy of the License at * + * * + * http://www.apache.org/licenses/LICENSE-2.0 * + * * + * Unless required by applicable law or agreed to in writing, software * + * distributed under the License is distributed on an "AS IS" BASIS, * + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * + * See the License for the specific language governing permissions and * + * limitations under the License. * + * * + ****************************************************************************** + * * + * Developers and authors: * + * Shay Gueron (1, 2), and Vlad Krasnov (1) * + * (1) Intel Corporation, Israel Development Center * + * (2) University of Haifa * + * Reference: * + * S.Gueron and V.Krasnov, "Fast Prime Field Elliptic Curve Cryptography with * + * 256 Bit Primes" * + * * + ******************************************************************************/ + +#include <string.h> + +#include <openssl/bn.h> +#include <openssl/err.h> +#include <openssl/ec.h> +#include "cryptlib.h" + +#include "ec_lcl.h" + +#if BN_BITS2 != 64 +# define TOBN(hi,lo) lo,hi +#else +# define TOBN(hi,lo) ((BN_ULONG)hi<<32|lo) +#endif + +#if defined(__GNUC__) +# define ALIGN32 __attribute((aligned(32))) +#elif defined(_MSC_VER) +# define ALIGN32 __declspec(align(32)) +#else +# define ALIGN32 +#endif + +#define ALIGNPTR(p,N) ((unsigned char *)p+N-(size_t)p%N) +#define P256_LIMBS (256/BN_BITS2) + +typedef unsigned short u16; + +typedef struct { + BN_ULONG X[P256_LIMBS]; + BN_ULONG Y[P256_LIMBS]; + BN_ULONG Z[P256_LIMBS]; +} P256_POINT; + +typedef struct { + BN_ULONG X[P256_LIMBS]; + BN_ULONG Y[P256_LIMBS]; +} P256_POINT_AFFINE; + +typedef P256_POINT_AFFINE PRECOMP256_ROW[64]; + +/* structure for precomputed multiples of the generator */ +typedef struct ec_pre_comp_st { + const EC_GROUP *group; /* Parent EC_GROUP object */ + size_t w; /* Window size */ + /* + * Constant time access to the X and Y coordinates of the pre-computed, + * generator multiplies, in the Montgomery domain. Pre-calculated + * multiplies are stored in affine form. + */ + PRECOMP256_ROW *precomp; + void *precomp_storage; + int references; +} EC_PRE_COMP; + +/* Functions implemented in assembly */ +/* Modular mul by 2: res = 2*a mod P */ +void ecp_nistz256_mul_by_2(BN_ULONG res[P256_LIMBS], + const BN_ULONG a[P256_LIMBS]); +/* Modular div by 2: res = a/2 mod P */ +void ecp_nistz256_div_by_2(BN_ULONG res[P256_LIMBS], + const BN_ULONG a[P256_LIMBS]); +/* Modular mul by 3: res = 3*a mod P */ +void ecp_nistz256_mul_by_3(BN_ULONG res[P256_LIMBS], + const BN_ULONG a[P256_LIMBS]); +/* Modular add: res = a+b mod P */ +void ecp_nistz256_add(BN_ULONG res[P256_LIMBS], + const BN_ULONG a[P256_LIMBS], + const BN_ULONG b[P256_LIMBS]); +/* Modular sub: res = a-b mod P */ +void ecp_nistz256_sub(BN_ULONG res[P256_LIMBS], + const BN_ULONG a[P256_LIMBS], + const BN_ULONG b[P256_LIMBS]); +/* Modular neg: res = -a mod P */ +void ecp_nistz256_neg(BN_ULONG res[P256_LIMBS], const BN_ULONG a[P256_LIMBS]); +/* Montgomery mul: res = a*b*2^-256 mod P */ +void ecp_nistz256_mul_mont(BN_ULONG res[P256_LIMBS], + const BN_ULONG a[P256_LIMBS], + const BN_ULONG b[P256_LIMBS]); +/* Montgomery sqr: res = a*a*2^-256 mod P */ +void ecp_nistz256_sqr_mont(BN_ULONG res[P256_LIMBS], + const BN_ULONG a[P256_LIMBS]); +/* Convert a number from Montgomery domain, by multiplying with 1 */ +void ecp_nistz256_from_mont(BN_ULONG res[P256_LIMBS], + const BN_ULONG in[P256_LIMBS]); +/* Convert a number to Montgomery domain, by multiplying with 2^512 mod P*/ +void ecp_nistz256_to_mont(BN_ULONG res[P256_LIMBS], + const BN_ULONG in[P256_LIMBS]); +/* Functions that perform constant time access to the precomputed tables */ +void ecp_nistz256_select_w5(P256_POINT * val, + const P256_POINT * in_t, int index); +void ecp_nistz256_select_w7(P256_POINT_AFFINE * val, + const P256_POINT_AFFINE * in_t, int index); + +/* One converted into the Montgomery domain */ +static const BN_ULONG ONE[P256_LIMBS] = { + TOBN(0x00000000, 0x00000001), TOBN(0xffffffff, 0x00000000), + TOBN(0xffffffff, 0xffffffff), TOBN(0x00000000, 0xfffffffe) +}; + +static void *ecp_nistz256_pre_comp_dup(void *); +static void ecp_nistz256_pre_comp_free(void *); +static void ecp_nistz256_pre_comp_clear_free(void *); +static EC_PRE_COMP *ecp_nistz256_pre_comp_new(const EC_GROUP *group); + +/* Precomputed tables for the default generator */ +#include "ecp_nistz256_table.c" + +/* Recode window to a signed digit, see ecp_nistputil.c for details */ +static unsigned int _booth_recode_w5(unsigned int in) +{ + unsigned int s, d; + + s = ~((in >> 5) - 1); + d = (1 << 6) - in - 1; + d = (d & s) | (in & ~s); + d = (d >> 1) + (d & 1); + + return (d << 1) + (s & 1); +} + +static unsigned int _booth_recode_w7(unsigned int in) +{ + unsigned int s, d; + + s = ~((in >> 7) - 1); + d = (1 << 8) - in - 1; + d = (d & s) | (in & ~s); + d = (d >> 1) + (d & 1); + + return (d << 1) + (s & 1); +} + +static void copy_conditional(BN_ULONG dst[P256_LIMBS], + const BN_ULONG src[P256_LIMBS], BN_ULONG move) +{ + BN_ULONG mask1 = -move; + BN_ULONG mask2 = ~mask1; + + dst[0] = (src[0] & mask1) ^ (dst[0] & mask2); + dst[1] = (src[1] & mask1) ^ (dst[1] & mask2); + dst[2] = (src[2] & mask1) ^ (dst[2] & mask2); + dst[3] = (src[3] & mask1) ^ (dst[3] & mask2); + if (P256_LIMBS == 8) { + dst[4] = (src[4] & mask1) ^ (dst[4] & mask2); + dst[5] = (src[5] & mask1) ^ (dst[5] & mask2); + dst[6] = (src[6] & mask1) ^ (dst[6] & mask2); + dst[7] = (src[7] & mask1) ^ (dst[7] & mask2); + } +} + +static BN_ULONG is_zero(BN_ULONG in) +{ + in |= (0 - in); + in = ~in; + in &= BN_MASK2; + in >>= BN_BITS2 - 1; + return in; +} + +static BN_ULONG is_equal(const BN_ULONG a[P256_LIMBS], + const BN_ULONG b[P256_LIMBS]) +{ + BN_ULONG res; + + res = a[0] ^ b[0]; + res |= a[1] ^ b[1]; + res |= a[2] ^ b[2]; + res |= a[3] ^ b[3]; + if (P256_LIMBS == 8) { + res |= a[4] ^ b[4]; + res |= a[5] ^ b[5]; + res |= a[6] ^ b[6]; + res |= a[7] ^ b[7]; + } + + return is_zero(res); +} + +static BN_ULONG is_one(const BN_ULONG a[P256_LIMBS]) +{ + BN_ULONG res; + + res = a[0] ^ ONE[0]; + res |= a[1] ^ ONE[1]; + res |= a[2] ^ ONE[2]; + res |= a[3] ^ ONE[3]; + if (P256_LIMBS == 8) { + res |= a[4] ^ ONE[4]; + res |= a[5] ^ ONE[5]; + res |= a[6] ^ ONE[6]; + } + + return is_zero(res); +} + +#ifndef ECP_NISTZ256_REFERENCE_IMPLEMENTATION +void ecp_nistz256_point_double(P256_POINT *r, const P256_POINT *a); +void ecp_nistz256_point_add(P256_POINT *r, + const P256_POINT *a, const P256_POINT *b); +void ecp_nistz256_point_add_affine(P256_POINT *r, + const P256_POINT *a, + const P256_POINT_AFFINE *b); +#else +/* Point double: r = 2*a */ +static void ecp_nistz256_point_double(P256_POINT *r, const P256_POINT *a) +{ + BN_ULONG S[P256_LIMBS]; + BN_ULONG M[P256_LIMBS]; + BN_ULONG Zsqr[P256_LIMBS]; + BN_ULONG tmp0[P256_LIMBS]; + + const BN_ULONG *in_x = a->X; + const BN_ULONG *in_y = a->Y; + const BN_ULONG *in_z = a->Z; + + BN_ULONG *res_x = r->X; + BN_ULONG *res_y = r->Y; + BN_ULONG *res_z = r->Z; + + ecp_nistz256_mul_by_2(S, in_y); + + ecp_nistz256_sqr_mont(Zsqr, in_z); + + ecp_nistz256_sqr_mont(S, S); + + ecp_nistz256_mul_mont(res_z, in_z, in_y); + ecp_nistz256_mul_by_2(res_z, res_z); + + ecp_nistz256_add(M, in_x, Zsqr); + ecp_nistz256_sub(Zsqr, in_x, Zsqr); + + ecp_nistz256_sqr_mont(res_y, S); + ecp_nistz256_div_by_2(res_y, res_y); + + ecp_nistz256_mul_mont(M, M, Zsqr); + ecp_nistz256_mul_by_3(M, M); + + ecp_nistz256_mul_mont(S, S, in_x); + ecp_nistz256_mul_by_2(tmp0, S); + + ecp_nistz256_sqr_mont(res_x, M); + + ecp_nistz256_sub(res_x, res_x, tmp0); + ecp_nistz256_sub(S, S, res_x); + + ecp_nistz256_mul_mont(S, S, M); + ecp_nistz256_sub(res_y, S, res_y); +} + +/* Point addition: r = a+b */ +static void ecp_nistz256_point_add(P256_POINT *r, + const P256_POINT *a, const P256_POINT *b) +{ + BN_ULONG U2[P256_LIMBS], S2[P256_LIMBS]; + BN_ULONG U1[P256_LIMBS], S1[P256_LIMBS]; + BN_ULONG Z1sqr[P256_LIMBS]; + BN_ULONG Z2sqr[P256_LIMBS]; + BN_ULONG H[P256_LIMBS], R[P256_LIMBS]; + BN_ULONG Hsqr[P256_LIMBS]; + BN_ULONG Rsqr[P256_LIMBS]; + BN_ULONG Hcub[P256_LIMBS]; + + BN_ULONG res_x[P256_LIMBS]; + BN_ULONG res_y[P256_LIMBS]; + BN_ULONG res_z[P256_LIMBS]; + + BN_ULONG in1infty, in2infty; + + const BN_ULONG *in1_x = a->X; + const BN_ULONG *in1_y = a->Y; + const BN_ULONG *in1_z = a->Z; + + const BN_ULONG *in2_x = b->X; + const BN_ULONG *in2_y = b->Y; + const BN_ULONG *in2_z = b->Z; + + /* We encode infinity as (0,0), which is not on the curve, + * so it is OK. */ + in1infty = (in1_x[0] | in1_x[1] | in1_x[2] | in1_x[3] | + in1_y[0] | in1_y[1] | in1_y[2] | in1_y[3]); + if (P256_LIMBS == 8) + in1infty |= (in1_x[4] | in1_x[5] | in1_x[6] | in1_x[7] | + in1_y[4] | in1_y[5] | in1_y[6] | in1_y[7]); + + in2infty = (in2_x[0] | in2_x[1] | in2_x[2] | in2_x[3] | + in2_y[0] | in2_y[1] | in2_y[2] | in2_y[3]); + if (P256_LIMBS == 8) + in2infty |= (in2_x[4] | in2_x[5] | in2_x[6] | in2_x[7] | + in2_y[4] | in2_y[5] | in2_y[6] | in2_y[7]); + + in1infty = is_zero(in1infty); + in2infty = is_zero(in2infty); + + ecp_nistz256_sqr_mont(Z2sqr, in2_z); /* Z2^2 */ + ecp_nistz256_sqr_mont(Z1sqr, in1_z); /* Z1^2 */ + + ecp_nistz256_mul_mont(S1, Z2sqr, in2_z); /* S1 = Z2^3 */ + ecp_nistz256_mul_mont(S2, Z1sqr, in1_z); /* S2 = Z1^3 */ + + ecp_nistz256_mul_mont(S1, S1, in1_y); /* S1 = Y1*Z2^3 */ + ecp_nistz256_mul_mont(S2, S2, in2_y); /* S2 = Y2*Z1^3 */ + ecp_nistz256_sub(R, S2, S1); /* R = S2 - S1 */ + + ecp_nistz256_mul_mont(U1, in1_x, Z2sqr); /* U1 = X1*Z2^2 */ + ecp_nistz256_mul_mont(U2, in2_x, Z1sqr); /* U2 = X2*Z1^2 */ + ecp_nistz256_sub(H, U2, U1); /* H = U2 - U1 */ + + /* + * This should not happen during sign/ecdh, so no constant time violation + */ + if (is_equal(U1, U2) && !in1infty && !in2infty) { + if (is_equal(S1, S2)) { + ecp_nistz256_point_double(r, a); + return; + } else { + memset(r, 0, sizeof(*r)); + return; + } + } + + ecp_nistz256_sqr_mont(Rsqr, R); /* R^2 */ + ecp_nistz256_mul_mont(res_z, H, in1_z); /* Z3 = H*Z1*Z2 */ + ecp_nistz256_sqr_mont(Hsqr, H); /* H^2 */ + ecp_nistz256_mul_mont(res_z, res_z, in2_z); /* Z3 = H*Z1*Z2 */ + ecp_nistz256_mul_mont(Hcub, Hsqr, H); /* H^3 */ + + ecp_nistz256_mul_mont(U2, U1, Hsqr); /* U1*H^2 */ + ecp_nistz256_mul_by_2(Hsqr, U2); /* 2*U1*H^2 */ + + ecp_nistz256_sub(res_x, Rsqr, Hsqr); + ecp_nistz256_sub(res_x, res_x, Hcub); + + ecp_nistz256_sub(res_y, U2, res_x); + + ecp_nistz256_mul_mont(S2, S1, Hcub); + ecp_nistz256_mul_mont(res_y, R, res_y); + ecp_nistz256_sub(res_y, res_y, S2); + + copy_conditional(res_x, in2_x, in1infty); + copy_conditional(res_y, in2_y, in1infty); + copy_conditional(res_z, in2_z, in1infty); + + copy_conditional(res_x, in1_x, in2infty); + copy_conditional(res_y, in1_y, in2infty); + copy_conditional(res_z, in1_z, in2infty); + + memcpy(r->X, res_x, sizeof(res_x)); + memcpy(r->Y, res_y, sizeof(res_y)); + memcpy(r->Z, res_z, sizeof(res_z)); +} + +/* Point addition when b is known to be affine: r = a+b */ +static void ecp_nistz256_point_add_affine(P256_POINT *r, + const P256_POINT *a, + const P256_POINT_AFFINE *b) +{ + BN_ULONG U2[P256_LIMBS], S2[P256_LIMBS]; + BN_ULONG Z1sqr[P256_LIMBS]; + BN_ULONG H[P256_LIMBS], R[P256_LIMBS]; + BN_ULONG Hsqr[P256_LIMBS]; + BN_ULONG Rsqr[P256_LIMBS]; + BN_ULONG Hcub[P256_LIMBS]; + + BN_ULONG res_x[P256_LIMBS]; + BN_ULONG res_y[P256_LIMBS]; + BN_ULONG res_z[P256_LIMBS]; + + BN_ULONG in1infty, in2infty; + + const BN_ULONG *in1_x = a->X; + const BN_ULONG *in1_y = a->Y; + const BN_ULONG *in1_z = a->Z; + + const BN_ULONG *in2_x = b->X; + const BN_ULONG *in2_y = b->Y; + + /* + * In affine representation we encode infty as (0,0), which is not on the + * curve, so it is OK + */ + in1infty = (in1_x[0] | in1_x[1] | in1_x[2] | in1_x[3] | + in1_y[0] | in1_y[1] | in1_y[2] | in1_y[3]); + if (P256_LIMBS == 8) + in1infty |= (in1_x[4] | in1_x[5] | in1_x[6] | in1_x[7] | + in1_y[4] | in1_y[5] | in1_y[6] | in1_y[7]); + + in2infty = (in2_x[0] | in2_x[1] | in2_x[2] | in2_x[3] | + in2_y[0] | in2_y[1] | in2_y[2] | in2_y[3]); + if (P256_LIMBS == 8) + in2infty |= (in2_x[4] | in2_x[5] | in2_x[6] | in2_x[7] | + in2_y[4] | in2_y[5] | in2_y[6] | in2_y[7]); + + in1infty = is_zero(in1infty); + in2infty = is_zero(in2infty); + + ecp_nistz256_sqr_mont(Z1sqr, in1_z); /* Z1^2 */ + + ecp_nistz256_mul_mont(U2, in2_x, Z1sqr); /* U2 = X2*Z1^2 */ + ecp_nistz256_sub(H, U2, in1_x); /* H = U2 - U1 */ + + ecp_nistz256_mul_mont(S2, Z1sqr, in1_z); /* S2 = Z1^3 */ + + ecp_nistz256_mul_mont(res_z, H, in1_z); /* Z3 = H*Z1*Z2 */ + + ecp_nistz256_mul_mont(S2, S2, in2_y); /* S2 = Y2*Z1^3 */ + ecp_nistz256_sub(R, S2, in1_y); /* R = S2 - S1 */ + + ecp_nistz256_sqr_mont(Hsqr, H); /* H^2 */ + ecp_nistz256_sqr_mont(Rsqr, R); /* R^2 */ + ecp_nistz256_mul_mont(Hcub, Hsqr, H); /* H^3 */ + + ecp_nistz256_mul_mont(U2, in1_x, Hsqr); /* U1*H^2 */ + ecp_nistz256_mul_by_2(Hsqr, U2); /* 2*U1*H^2 */ + + ecp_nistz256_sub(res_x, Rsqr, Hsqr); + ecp_nistz256_sub(res_x, res_x, Hcub); + ecp_nistz256_sub(H, U2, res_x); + + ecp_nistz256_mul_mont(S2, in1_y, Hcub); + ecp_nistz256_mul_mont(H, H, R); + ecp_nistz256_sub(res_y, H, S2); + + copy_conditional(res_x, in2_x, in1infty); + copy_conditional(res_x, in1_x, in2infty); + + copy_conditional(res_y, in2_y, in1infty); + copy_conditional(res_y, in1_y, in2infty); + + copy_conditional(res_z, ONE, in1infty); + copy_conditional(res_z, in1_z, in2infty); + + memcpy(r->X, res_x, sizeof(res_x)); + memcpy(r->Y, res_y, sizeof(res_y)); + memcpy(r->Z, res_z, sizeof(res_z)); +} +#endif + +/* r = in^-1 mod p */ +static void ecp_nistz256_mod_inverse(BN_ULONG r[P256_LIMBS], + const BN_ULONG in[P256_LIMBS]) +{ + /* + * The poly is ffffffff 00000001 00000000 00000000 00000000 ffffffff + * ffffffff ffffffff We use FLT and used poly-2 as exponent + */ + BN_ULONG p2[P256_LIMBS]; + BN_ULONG p4[P256_LIMBS]; + BN_ULONG p8[P256_LIMBS]; + BN_ULONG p16[P256_LIMBS]; + BN_ULONG p32[P256_LIMBS]; + BN_ULONG res[P256_LIMBS]; + int i; + + ecp_nistz256_sqr_mont(res, in); + ecp_nistz256_mul_mont(p2, res, in); /* 3*p */ + + ecp_nistz256_sqr_mont(res, p2); + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(p4, res, p2); /* f*p */ + + ecp_nistz256_sqr_mont(res, p4); + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(p8, res, p4); /* ff*p */ + + ecp_nistz256_sqr_mont(res, p8); + for (i = 0; i < 7; i++) + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(p16, res, p8); /* ffff*p */ + + ecp_nistz256_sqr_mont(res, p16); + for (i = 0; i < 15; i++) + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(p32, res, p16); /* ffffffff*p */ + + ecp_nistz256_sqr_mont(res, p32); + for (i = 0; i < 31; i++) + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(res, res, in); + + for (i = 0; i < 32 * 4; i++) + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(res, res, p32); + + for (i = 0; i < 32; i++) + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(res, res, p32); + + for (i = 0; i < 16; i++) + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(res, res, p16); + + for (i = 0; i < 8; i++) + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(res, res, p8); + + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(res, res, p4); + + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(res, res, p2); + + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_sqr_mont(res, res); + ecp_nistz256_mul_mont(res, res, in); + + memcpy(r, res, sizeof(res)); +} + +/* + * ecp_nistz256_bignum_to_field_elem copies the contents of |in| to |out| and + * returns one if it fits. Otherwise it returns zero. + */ +static int ecp_nistz256_bignum_to_field_elem(BN_ULONG out[P256_LIMBS], + const BIGNUM *in) +{ + if (in->top > P256_LIMBS) + return 0; + + memset(out, 0, sizeof(BN_ULONG) * P256_LIMBS); + memcpy(out, in->d, sizeof(BN_ULONG) * in->top); + return 1; +} + +/* r = sum(scalar[i]*point[i]) */ +static void ecp_nistz256_windowed_mul(const EC_GROUP *group, + P256_POINT *r, + const BIGNUM **scalar, + const EC_POINT **point, + int num, BN_CTX *ctx) +{ + int i, j; + unsigned int index; + unsigned char (*p_str)[33] = NULL; + const unsigned int window_size = 5; + const unsigned int mask = (1 << (window_size + 1)) - 1; + unsigned int wvalue; + BN_ULONG tmp[P256_LIMBS]; + ALIGN32 P256_POINT h; + const BIGNUM **scalars = NULL; + P256_POINT (*table)[16] = NULL; + void *table_storage = NULL; + + if ((table_storage = + OPENSSL_malloc(num * 16 * sizeof(P256_POINT) + 64)) == NULL + || (p_str = + OPENSSL_malloc(num * 33 * sizeof(unsigned char))) == NULL + || (scalars = OPENSSL_malloc(num * sizeof(BIGNUM *))) == NULL) { + ECerr(EC_F_ECP_NISTZ256_WINDOWED_MUL, ERR_R_MALLOC_FAILURE); + goto err; + } else { + table = (void *)ALIGNPTR(table_storage, 64); + } + + for (i = 0; i < num; i++) { + P256_POINT *row = table[i]; + + if ((BN_num_bits(scalar[i]) > 256) || BN_is_negative(scalar[i])) { + BIGNUM *mod; + + if ((mod = BN_CTX_get(ctx)) == NULL) + goto err; + if (!BN_nnmod(mod, scalar[i], &group->order, ctx)) { + ECerr(EC_F_ECP_NISTZ256_WINDOWED_MUL, ERR_R_BN_LIB); + goto err; + } + scalars[i] = mod; + } else + scalars[i] = scalar[i]; + + for (j = 0; j < scalars[i]->top * BN_BYTES; j += BN_BYTES) { + BN_ULONG d = scalars[i]->d[j / BN_BYTES]; + + p_str[i][j + 0] = d & 0xff; + p_str[i][j + 1] = (d >> 8) & 0xff; + p_str[i][j + 2] = (d >> 16) & 0xff; + p_str[i][j + 3] = (d >>= 24) & 0xff; + if (BN_BYTES == 8) { + d >>= 8; + p_str[i][j + 4] = d & 0xff; + p_str[i][j + 5] = (d >> 8) & 0xff; + p_str[i][j + 6] = (d >> 16) & 0xff; + p_str[i][j + 7] = (d >> 24) & 0xff; + } + } + for (; j < 33; j++) + p_str[i][j] = 0; + + /* table[0] is implicitly (0,0,0) (the point at infinity), + * therefore it is not stored. All other values are actually + * stored with an offset of -1 in table. + */ + + if (!ecp_nistz256_bignum_to_field_elem(row[1 - 1].X, &point[i]->X) + || !ecp_nistz256_bignum_to_field_elem(row[1 - 1].Y, &point[i]->Y) + || !ecp_nistz256_bignum_to_field_elem(row[1 - 1].Z, &point[i]->Z)) { + ECerr(EC_F_ECP_NISTZ256_WINDOWED_MUL, EC_R_COORDINATES_OUT_OF_RANGE); + goto err; + } + + ecp_nistz256_point_double(&row[ 2 - 1], &row[ 1 - 1]); + ecp_nistz256_point_add (&row[ 3 - 1], &row[ 2 - 1], &row[1 - 1]); + ecp_nistz256_point_double(&row[ 4 - 1], &row[ 2 - 1]); + ecp_nistz256_point_double(&row[ 6 - 1], &row[ 3 - 1]); + ecp_nistz256_point_double(&row[ 8 - 1], &row[ 4 - 1]); + ecp_nistz256_point_double(&row[12 - 1], &row[ 6 - 1]); + ecp_nistz256_point_add (&row[ 5 - 1], &row[ 4 - 1], &row[1 - 1]); + ecp_nistz256_point_add (&row[ 7 - 1], &row[ 6 - 1], &row[1 - 1]); + ecp_nistz256_point_add (&row[ 9 - 1], &row[ 8 - 1], &row[1 - 1]); + ecp_nistz256_point_add (&row[13 - 1], &row[12 - 1], &row[1 - 1]); + ecp_nistz256_point_double(&row[14 - 1], &row[ 7 - 1]); + ecp_nistz256_point_double(&row[10 - 1], &row[ 5 - 1]); + ecp_nistz256_point_add (&row[15 - 1], &row[14 - 1], &row[1 - 1]); + ecp_nistz256_point_add (&row[11 - 1], &row[10 - 1], &row[1 - 1]); + ecp_nistz256_point_add (&row[16 - 1], &row[15 - 1], &row[1 - 1]); + } + + index = 255; + + wvalue = p_str[0][(index - 1) / 8]; + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + + ecp_nistz256_select_w5(r, table[0], _booth_recode_w5(wvalue) >> 1); + + while (index >= 5) { + for (i = (index == 255 ? 1 : 0); i < num; i++) { + unsigned int off = (index - 1) / 8; + + wvalue = p_str[i][off] | p_str[i][off + 1] << 8; + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + + wvalue = _booth_recode_w5(wvalue); + + ecp_nistz256_select_w5(&h, table[i], wvalue >> 1); + + ecp_nistz256_neg(tmp, h.Y); + copy_conditional(h.Y, tmp, (wvalue & 1)); + + ecp_nistz256_point_add(r, r, &h); + } + + index -= window_size; + + ecp_nistz256_point_double(r, r); + ecp_nistz256_point_double(r, r); + ecp_nistz256_point_double(r, r); + ecp_nistz256_point_double(r, r); + ecp_nistz256_point_double(r, r); + } + + /* Final window */ + for (i = 0; i < num; i++) { + wvalue = p_str[i][0]; + wvalue = (wvalue << 1) & mask; + + wvalue = _booth_recode_w5(wvalue); + + ecp_nistz256_select_w5(&h, table[i], wvalue >> 1); + + ecp_nistz256_neg(tmp, h.Y); + copy_conditional(h.Y, tmp, wvalue & 1); + + ecp_nistz256_point_add(r, r, &h); + } + + err: + if (table_storage) + OPENSSL_free(table_storage); + if (p_str) + OPENSSL_free(p_str); + if (scalars) + OPENSSL_free(scalars); +} + +/* Coordinates of G, for which we have precomputed tables */ +const static BN_ULONG def_xG[P256_LIMBS] = { + TOBN(0x79e730d4, 0x18a9143c), TOBN(0x75ba95fc, 0x5fedb601), + TOBN(0x79fb732b, 0x77622510), TOBN(0x18905f76, 0xa53755c6) +}; + +const static BN_ULONG def_yG[P256_LIMBS] = { + TOBN(0xddf25357, 0xce95560a), TOBN(0x8b4ab8e4, 0xba19e45c), + TOBN(0xd2e88688, 0xdd21f325), TOBN(0x8571ff18, 0x25885d85) +}; + +/* + * ecp_nistz256_is_affine_G returns one if |generator| is the standard, P-256 + * generator. + */ +static int ecp_nistz256_is_affine_G(const EC_POINT *generator) +{ + return (generator->X.top == P256_LIMBS) && + (generator->Y.top == P256_LIMBS) && + (generator->Z.top == (P256_LIMBS - P256_LIMBS / 8)) && + is_equal(generator->X.d, def_xG) && + is_equal(generator->Y.d, def_yG) && is_one(generator->Z.d); +} + +static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx) +{ + /* + * We precompute a table for a Booth encoded exponent (wNAF) based + * computation. Each table holds 64 values for safe access, with an + * implicit value of infinity at index zero. We use window of size 7, and + * therefore require ceil(256/7) = 37 tables. + */ + BIGNUM *order; + EC_POINT *P = NULL, *T = NULL; + const EC_POINT *generator; + EC_PRE_COMP *pre_comp; + int i, j, k, ret = 0; + size_t w; + + PRECOMP256_ROW *preComputedTable = NULL; + unsigned char *precomp_storage = NULL; + + /* if there is an old EC_PRE_COMP object, throw it away */ + EC_EX_DATA_free_data(&group->extra_data, ecp_nistz256_pre_comp_dup, + ecp_nistz256_pre_comp_free, + ecp_nistz256_pre_comp_clear_free); + + generator = EC_GROUP_get0_generator(group); + if (generator == NULL) { + ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE, EC_R_UNDEFINED_GENERATOR); + return 0; + } + + if (ecp_nistz256_is_affine_G(generator)) { + /* + * No need to calculate tables for the standard generator because we + * have them statically. + */ + return 1; + } + + if ((pre_comp = ecp_nistz256_pre_comp_new(group)) == NULL) + return 0; + + if (ctx == NULL) { + ctx = BN_CTX_new(); + if (ctx == NULL) + goto err; + } + + BN_CTX_start(ctx); + order = BN_CTX_get(ctx); + + if (order == NULL) + goto err; + + if (!EC_GROUP_get_order(group, order, ctx)) + goto err; + + if (BN_is_zero(order)) { + ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE, EC_R_UNKNOWN_ORDER); + goto err; + } + + w = 7; + + if ((precomp_storage = + OPENSSL_malloc(37 * 64 * sizeof(P256_POINT_AFFINE) + 64)) == NULL) { + ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE, ERR_R_MALLOC_FAILURE); + goto err; + } else { + preComputedTable = (void *)ALIGNPTR(precomp_storage, 64); + } + + P = EC_POINT_new(group); + T = EC_POINT_new(group); + + /* + * The zero entry is implicitly infinity, and we skip it, storing other + * values with -1 offset. + */ + EC_POINT_copy(T, generator); + + for (k = 0; k < 64; k++) { + EC_POINT_copy(P, T); + for (j = 0; j < 37; j++) { + /* + * It would be faster to use + * ec_GFp_simple_points_make_affine and make multiple + * points affine at the same time. + */ + ec_GFp_simple_make_affine(group, P, ctx); + ecp_nistz256_bignum_to_field_elem(preComputedTable[j] + [k].X, &P->X); + ecp_nistz256_bignum_to_field_elem(preComputedTable[j] + [k].Y, &P->Y); + for (i = 0; i < 7; i++) + ec_GFp_simple_dbl(group, P, P, ctx); + } + ec_GFp_simple_add(group, T, T, generator, ctx); + } + + pre_comp->group = group; + pre_comp->w = w; + pre_comp->precomp = preComputedTable; + pre_comp->precomp_storage = precomp_storage; + + precomp_storage = NULL; + + if (!EC_EX_DATA_set_data(&group->extra_data, pre_comp, + ecp_nistz256_pre_comp_dup, + ecp_nistz256_pre_comp_free, + ecp_nistz256_pre_comp_clear_free)) { + goto err; + } + + pre_comp = NULL; + + ret = 1; + + err: + if (ctx != NULL) + BN_CTX_end(ctx); + if (pre_comp) + ecp_nistz256_pre_comp_free(pre_comp); + if (precomp_storage) + OPENSSL_free(precomp_storage); + if (P) + EC_POINT_free(P); + if (T) + EC_POINT_free(T); + return ret; +} + +/* + * Note that by default ECP_NISTZ256_AVX2 is undefined. While it's great + * code processing 4 points in parallel, corresponding serial operation + * is several times slower, because it uses 29x29=58-bit multiplication + * as opposite to 64x64=128-bit in integer-only scalar case. As result + * it doesn't provide *significant* performance improvement. Note that + * just defining ECP_NISTZ256_AVX2 is not sufficient to make it work, + * you'd need to compile even asm/ecp_nistz256-avx.pl module. + */ +#if defined(ECP_NISTZ256_AVX2) +# if !(defined(__x86_64) || defined(__x86_64__)) || \ + defined(_M_AMD64) || defined(_MX64)) || \ + !(defined(__GNUC__) || defined(_MSC_VER)) /* this is for ALIGN32 */ +# undef ECP_NISTZ256_AVX2 +# else +/* Constant time access, loading four values, from four consecutive tables */ +void ecp_nistz256_avx2_select_w7(P256_POINT_AFFINE * val, + const P256_POINT_AFFINE * in_t, int index); +void ecp_nistz256_avx2_multi_select_w7(void *result, const void *in, int index0, + int index1, int index2, int index3); +void ecp_nistz256_avx2_transpose_convert(void *RESULTx4, const void *in); +void ecp_nistz256_avx2_convert_transpose_back(void *result, const void *Ax4); +void ecp_nistz256_avx2_point_add_affine_x4(void *RESULTx4, const void *Ax4, + const void *Bx4); +void ecp_nistz256_avx2_point_add_affines_x4(void *RESULTx4, const void *Ax4, + const void *Bx4); +void ecp_nistz256_avx2_to_mont(void *RESULTx4, const void *Ax4); +void ecp_nistz256_avx2_from_mont(void *RESULTx4, const void *Ax4); +void ecp_nistz256_avx2_set1(void *RESULTx4); +int ecp_nistz_avx2_eligible(void); + +static void booth_recode_w7(unsigned char *sign, + unsigned char *digit, unsigned char in) +{ + unsigned char s, d; + + s = ~((in >> 7) - 1); + d = (1 << 8) - in - 1; + d = (d & s) | (in & ~s); + d = (d >> 1) + (d & 1); + + *sign = s & 1; + *digit = d; +} + +/* + * ecp_nistz256_avx2_mul_g performs multiplication by G, using only the + * precomputed table. It does 4 affine point additions in parallel, + * significantly speeding up point multiplication for a fixed value. + */ +static void ecp_nistz256_avx2_mul_g(P256_POINT *r, + unsigned char p_str[33], + const P256_POINT_AFFINE(*preComputedTable)[64]) +{ + const unsigned int window_size = 7; + const unsigned int mask = (1 << (window_size + 1)) - 1; + unsigned int wvalue; + /* Using 4 windows at a time */ + unsigned char sign0, digit0; + unsigned char sign1, digit1; + unsigned char sign2, digit2; + unsigned char sign3, digit3; + unsigned int index = 0; + BN_ULONG tmp[P256_LIMBS]; + int i; + + ALIGN32 BN_ULONG aX4[4 * 9 * 3] = { 0 }; + ALIGN32 BN_ULONG bX4[4 * 9 * 2] = { 0 }; + ALIGN32 P256_POINT_AFFINE point_arr[P256_LIMBS]; + ALIGN32 P256_POINT res_point_arr[P256_LIMBS]; + + /* Initial four windows */ + wvalue = *((u16 *) & p_str[0]); + wvalue = (wvalue << 1) & mask; + index += window_size; + booth_recode_w7(&sign0, &digit0, wvalue); + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign1, &digit1, wvalue); + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign2, &digit2, wvalue); + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign3, &digit3, wvalue); + + ecp_nistz256_avx2_multi_select_w7(point_arr, preComputedTable[0], + digit0, digit1, digit2, digit3); + + ecp_nistz256_neg(tmp, point_arr[0].Y); + copy_conditional(point_arr[0].Y, tmp, sign0); + ecp_nistz256_neg(tmp, point_arr[1].Y); + copy_conditional(point_arr[1].Y, tmp, sign1); + ecp_nistz256_neg(tmp, point_arr[2].Y); + copy_conditional(point_arr[2].Y, tmp, sign2); + ecp_nistz256_neg(tmp, point_arr[3].Y); + copy_conditional(point_arr[3].Y, tmp, sign3); + + ecp_nistz256_avx2_transpose_convert(aX4, point_arr); + ecp_nistz256_avx2_to_mont(aX4, aX4); + ecp_nistz256_avx2_to_mont(&aX4[4 * 9], &aX4[4 * 9]); + ecp_nistz256_avx2_set1(&aX4[4 * 9 * 2]); + + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign0, &digit0, wvalue); + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign1, &digit1, wvalue); + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign2, &digit2, wvalue); + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign3, &digit3, wvalue); + + ecp_nistz256_avx2_multi_select_w7(point_arr, preComputedTable[4 * 1], + digit0, digit1, digit2, digit3); + + ecp_nistz256_neg(tmp, point_arr[0].Y); + copy_conditional(point_arr[0].Y, tmp, sign0); + ecp_nistz256_neg(tmp, point_arr[1].Y); + copy_conditional(point_arr[1].Y, tmp, sign1); + ecp_nistz256_neg(tmp, point_arr[2].Y); + copy_conditional(point_arr[2].Y, tmp, sign2); + ecp_nistz256_neg(tmp, point_arr[3].Y); + copy_conditional(point_arr[3].Y, tmp, sign3); + + ecp_nistz256_avx2_transpose_convert(bX4, point_arr); + ecp_nistz256_avx2_to_mont(bX4, bX4); + ecp_nistz256_avx2_to_mont(&bX4[4 * 9], &bX4[4 * 9]); + /* Optimized when both inputs are affine */ + ecp_nistz256_avx2_point_add_affines_x4(aX4, aX4, bX4); + + for (i = 2; i < 9; i++) { + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign0, &digit0, wvalue); + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign1, &digit1, wvalue); + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign2, &digit2, wvalue); + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + booth_recode_w7(&sign3, &digit3, wvalue); + + ecp_nistz256_avx2_multi_select_w7(point_arr, + preComputedTable[4 * i], + digit0, digit1, digit2, digit3); + + ecp_nistz256_neg(tmp, point_arr[0].Y); + copy_conditional(point_arr[0].Y, tmp, sign0); + ecp_nistz256_neg(tmp, point_arr[1].Y); + copy_conditional(point_arr[1].Y, tmp, sign1); + ecp_nistz256_neg(tmp, point_arr[2].Y); + copy_conditional(point_arr[2].Y, tmp, sign2); + ecp_nistz256_neg(tmp, point_arr[3].Y); + copy_conditional(point_arr[3].Y, tmp, sign3); + + ecp_nistz256_avx2_transpose_convert(bX4, point_arr); + ecp_nistz256_avx2_to_mont(bX4, bX4); + ecp_nistz256_avx2_to_mont(&bX4[4 * 9], &bX4[4 * 9]); + + ecp_nistz256_avx2_point_add_affine_x4(aX4, aX4, bX4); + } + + ecp_nistz256_avx2_from_mont(&aX4[4 * 9 * 0], &aX4[4 * 9 * 0]); + ecp_nistz256_avx2_from_mont(&aX4[4 * 9 * 1], &aX4[4 * 9 * 1]); + ecp_nistz256_avx2_from_mont(&aX4[4 * 9 * 2], &aX4[4 * 9 * 2]); + + ecp_nistz256_avx2_convert_transpose_back(res_point_arr, aX4); + /* Last window is performed serially */ + wvalue = *((u16 *) & p_str[(index - 1) / 8]); + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + booth_recode_w7(&sign0, &digit0, wvalue); + ecp_nistz256_avx2_select_w7((P256_POINT_AFFINE *) r, + preComputedTable[36], digit0); + ecp_nistz256_neg(tmp, r->Y); + copy_conditional(r->Y, tmp, sign0); + memcpy(r->Z, ONE, sizeof(ONE)); + /* Sum the four windows */ + ecp_nistz256_point_add(r, r, &res_point_arr[0]); + ecp_nistz256_point_add(r, r, &res_point_arr[1]); + ecp_nistz256_point_add(r, r, &res_point_arr[2]); + ecp_nistz256_point_add(r, r, &res_point_arr[3]); +} +# endif +#endif + +static int ecp_nistz256_set_from_affine(EC_POINT *out, const EC_GROUP *group, + const P256_POINT_AFFINE *in, + BN_CTX *ctx) +{ + BIGNUM x, y; + BN_ULONG d_x[P256_LIMBS], d_y[P256_LIMBS]; + int ret = 0; + + memcpy(d_x, in->X, sizeof(d_x)); + x.d = d_x; + x.dmax = x.top = P256_LIMBS; + x.neg = 0; + x.flags = BN_FLG_STATIC_DATA; + + memcpy(d_y, in->Y, sizeof(d_y)); + y.d = d_y; + y.dmax = y.top = P256_LIMBS; + y.neg = 0; + y.flags = BN_FLG_STATIC_DATA; + + ret = EC_POINT_set_affine_coordinates_GFp(group, out, &x, &y, ctx); + + return ret; +} + +/* r = scalar*G + sum(scalars[i]*points[i]) */ +static int ecp_nistz256_points_mul(const EC_GROUP *group, + EC_POINT *r, + const BIGNUM *scalar, + size_t num, + const EC_POINT *points[], + const BIGNUM *scalars[], BN_CTX *ctx) +{ + int i = 0, ret = 0, no_precomp_for_generator = 0, p_is_infinity = 0; + size_t j; + unsigned char p_str[33] = { 0 }; + const PRECOMP256_ROW *preComputedTable = NULL; + const EC_PRE_COMP *pre_comp = NULL; + const EC_POINT *generator = NULL; + unsigned int index = 0; + const unsigned int window_size = 7; + const unsigned int mask = (1 << (window_size + 1)) - 1; + unsigned int wvalue; + ALIGN32 union { + P256_POINT p; + P256_POINT_AFFINE a; + } t, p; + BIGNUM *tmp_scalar; + + if (group->meth != r->meth) { + ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS); + return 0; + } + if ((scalar == NULL) && (num == 0)) + return EC_POINT_set_to_infinity(group, r); + + for (j = 0; j < num; j++) { + if (group->meth != points[j]->meth) { + ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS); + return 0; + } + } + + /* Need 256 bits for space for all coordinates. */ + bn_wexpand(&r->X, P256_LIMBS); + bn_wexpand(&r->Y, P256_LIMBS); + bn_wexpand(&r->Z, P256_LIMBS); + r->X.top = P256_LIMBS; + r->Y.top = P256_LIMBS; + r->Z.top = P256_LIMBS; + + if (scalar) { + generator = EC_GROUP_get0_generator(group); + if (generator == NULL) { + ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_UNDEFINED_GENERATOR); + goto err; + } + + /* look if we can use precomputed multiples of generator */ + pre_comp = + EC_EX_DATA_get_data(group->extra_data, ecp_nistz256_pre_comp_dup, + ecp_nistz256_pre_comp_free, + ecp_nistz256_pre_comp_clear_free); + + if (pre_comp) { + /* + * If there is a precomputed table for the generator, check that + * it was generated with the same generator. + */ + EC_POINT *pre_comp_generator = EC_POINT_new(group); + if (pre_comp_generator == NULL) + goto err; + + if (!ecp_nistz256_set_from_affine + (pre_comp_generator, group, pre_comp->precomp[0], ctx)) + goto err; + + if (0 == EC_POINT_cmp(group, generator, pre_comp_generator, ctx)) + preComputedTable = (const PRECOMP256_ROW *)pre_comp->precomp; + + EC_POINT_free(pre_comp_generator); + } + + if (preComputedTable == NULL && ecp_nistz256_is_affine_G(generator)) { + /* + * If there is no precomputed data, but the generator + * is the default, a hardcoded table of precomputed + * data is used. This is because applications, such as + * Apache, do not use EC_KEY_precompute_mult. + */ + preComputedTable = (const PRECOMP256_ROW *)ecp_nistz256_precomputed; + } + + if (preComputedTable) { + if ((BN_num_bits(scalar) > 256) + || BN_is_negative(scalar)) { + if ((tmp_scalar = BN_CTX_get(ctx)) == NULL) + goto err; + + if (!BN_nnmod(tmp_scalar, scalar, &group->order, ctx)) { + ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_BN_LIB); + goto err; + } + scalar = tmp_scalar; + } + + for (i = 0; i < scalar->top * BN_BYTES; i += BN_BYTES) { + BN_ULONG d = scalar->d[i / BN_BYTES]; + + p_str[i + 0] = d & 0xff; + p_str[i + 1] = (d >> 8) & 0xff; + p_str[i + 2] = (d >> 16) & 0xff; + p_str[i + 3] = (d >>= 24) & 0xff; + if (BN_BYTES == 8) { + d >>= 8; + p_str[i + 4] = d & 0xff; + p_str[i + 5] = (d >> 8) & 0xff; + p_str[i + 6] = (d >> 16) & 0xff; + p_str[i + 7] = (d >> 24) & 0xff; + } + } + + for (; i < 33; i++) + p_str[i] = 0; + +#if defined(ECP_NISTZ256_AVX2) + if (ecp_nistz_avx2_eligible()) { + ecp_nistz256_avx2_mul_g(&p.p, p_str, preComputedTable); + } else +#endif + { + /* First window */ + wvalue = (p_str[0] << 1) & mask; + index += window_size; + + wvalue = _booth_recode_w7(wvalue); + + ecp_nistz256_select_w7(&p.a, preComputedTable[0], wvalue >> 1); + + ecp_nistz256_neg(p.p.Z, p.p.Y); + copy_conditional(p.p.Y, p.p.Z, wvalue & 1); + + memcpy(p.p.Z, ONE, sizeof(ONE)); + + for (i = 1; i < 37; i++) { + unsigned int off = (index - 1) / 8; + wvalue = p_str[off] | p_str[off + 1] << 8; + wvalue = (wvalue >> ((index - 1) % 8)) & mask; + index += window_size; + + wvalue = _booth_recode_w7(wvalue); + + ecp_nistz256_select_w7(&t.a, + preComputedTable[i], wvalue >> 1); + + ecp_nistz256_neg(t.p.Z, t.a.Y); + copy_conditional(t.a.Y, t.p.Z, wvalue & 1); + + ecp_nistz256_point_add_affine(&p.p, &p.p, &t.a); + } + } + } else { + p_is_infinity = 1; + no_precomp_for_generator = 1; + } + } else + p_is_infinity = 1; + + if (no_precomp_for_generator) { + /* + * Without a precomputed table for the generator, it has to be + * handled like a normal point. + */ + const BIGNUM **new_scalars; + const EC_POINT **new_points; + + new_scalars = OPENSSL_malloc((num + 1) * sizeof(BIGNUM *)); + if (!new_scalars) { + ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE); + return 0; + } + + new_points = OPENSSL_malloc((num + 1) * sizeof(EC_POINT *)); + if (!new_points) { + OPENSSL_free(new_scalars); + ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE); + return 0; + } + + memcpy(new_scalars, scalars, num * sizeof(BIGNUM *)); + new_scalars[num] = scalar; + memcpy(new_points, points, num * sizeof(EC_POINT *)); + new_points[num] = generator; + + scalars = new_scalars; + points = new_points; + num++; + } + + if (num) { + P256_POINT *out = &t.p; + if (p_is_infinity) + out = &p.p; + + ecp_nistz256_windowed_mul(group, out, scalars, points, num, ctx); + + if (!p_is_infinity) + ecp_nistz256_point_add(&p.p, &p.p, out); + } + + if (no_precomp_for_generator) { + OPENSSL_free(points); + OPENSSL_free(scalars); + } + + memcpy(r->X.d, p.p.X, sizeof(p.p.X)); + memcpy(r->Y.d, p.p.Y, sizeof(p.p.Y)); + memcpy(r->Z.d, p.p.Z, sizeof(p.p.Z)); + bn_correct_top(&r->X); + bn_correct_top(&r->Y); + bn_correct_top(&r->Z); + + ret = 1; + + err: + return ret; +} + +static int ecp_nistz256_get_affine(const EC_GROUP *group, + const EC_POINT *point, + BIGNUM *x, BIGNUM *y, BN_CTX *ctx) +{ + BN_ULONG z_inv2[P256_LIMBS]; + BN_ULONG z_inv3[P256_LIMBS]; + BN_ULONG x_aff[P256_LIMBS]; + BN_ULONG y_aff[P256_LIMBS]; + BN_ULONG point_x[P256_LIMBS], point_y[P256_LIMBS], point_z[P256_LIMBS]; + + if (EC_POINT_is_at_infinity(group, point)) { + ECerr(EC_F_ECP_NISTZ256_GET_AFFINE, EC_R_POINT_AT_INFINITY); + return 0; + } + + if (!ecp_nistz256_bignum_to_field_elem(point_x, &point->X) || + !ecp_nistz256_bignum_to_field_elem(point_y, &point->Y) || + !ecp_nistz256_bignum_to_field_elem(point_z, &point->Z)) { + ECerr(EC_F_ECP_NISTZ256_GET_AFFINE, EC_R_COORDINATES_OUT_OF_RANGE); + return 0; + } + + ecp_nistz256_mod_inverse(z_inv3, point_z); + ecp_nistz256_sqr_mont(z_inv2, z_inv3); + ecp_nistz256_mul_mont(x_aff, z_inv2, point_x); + + if (x != NULL) { + bn_wexpand(x, P256_LIMBS); + x->top = P256_LIMBS; + ecp_nistz256_from_mont(x->d, x_aff); + bn_correct_top(x); + } + + if (y != NULL) { + ecp_nistz256_mul_mont(z_inv3, z_inv3, z_inv2); + ecp_nistz256_mul_mont(y_aff, z_inv3, point_y); + bn_wexpand(y, P256_LIMBS); + y->top = P256_LIMBS; + ecp_nistz256_from_mont(y->d, y_aff); + bn_correct_top(y); + } + + return 1; +} + +static EC_PRE_COMP *ecp_nistz256_pre_comp_new(const EC_GROUP *group) +{ + EC_PRE_COMP *ret = NULL; + + if (!group) + return NULL; + + ret = (EC_PRE_COMP *)OPENSSL_malloc(sizeof(EC_PRE_COMP)); + + if (!ret) { + ECerr(EC_F_ECP_NISTZ256_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE); + return ret; + } + + ret->group = group; + ret->w = 6; /* default */ + ret->precomp = NULL; + ret->precomp_storage = NULL; + ret->references = 1; + return ret; +} + +static void *ecp_nistz256_pre_comp_dup(void *src_) +{ + EC_PRE_COMP *src = src_; + + /* no need to actually copy, these objects never change! */ + CRYPTO_add(&src->references, 1, CRYPTO_LOCK_EC_PRE_COMP); + + return src_; +} + +static void ecp_nistz256_pre_comp_free(void *pre_) +{ + int i; + EC_PRE_COMP *pre = pre_; + + if (!pre) + return; + + i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP); + if (i > 0) + return; + + if (pre->precomp_storage) + OPENSSL_free(pre->precomp_storage); + + OPENSSL_free(pre); +} + +static void ecp_nistz256_pre_comp_clear_free(void *pre_) +{ + int i; + EC_PRE_COMP *pre = pre_; + + if (!pre) + return; + + i = CRYPTO_add(&pre->references, -1, CRYPTO_LOCK_EC_PRE_COMP); + if (i > 0) + return; + + if (pre->precomp_storage) { + OPENSSL_cleanse(pre->precomp, + 32 * sizeof(unsigned char) * (1 << pre->w) * 2 * 37); + OPENSSL_free(pre->precomp_storage); + } + OPENSSL_cleanse(pre, sizeof *pre); + OPENSSL_free(pre); +} + +static int ecp_nistz256_window_have_precompute_mult(const EC_GROUP *group) +{ + /* There is a hard-coded table for the default generator. */ + const EC_POINT *generator = EC_GROUP_get0_generator(group); + if (generator != NULL && ecp_nistz256_is_affine_G(generator)) { + /* There is a hard-coded table for the default generator. */ + return 1; + } + + return EC_EX_DATA_get_data(group->extra_data, ecp_nistz256_pre_comp_dup, + ecp_nistz256_pre_comp_free, + ecp_nistz256_pre_comp_clear_free) != NULL; +} + +const EC_METHOD *EC_GFp_nistz256_method(void) +{ + static const EC_METHOD ret = { + EC_FLAGS_DEFAULT_OCT, + NID_X9_62_prime_field, + ec_GFp_mont_group_init, + ec_GFp_mont_group_finish, + ec_GFp_mont_group_clear_finish, + ec_GFp_mont_group_copy, + ec_GFp_mont_group_set_curve, + ec_GFp_simple_group_get_curve, + ec_GFp_simple_group_get_degree, + ec_GFp_simple_group_check_discriminant, + ec_GFp_simple_point_init, + ec_GFp_simple_point_finish, + ec_GFp_simple_point_clear_finish, + ec_GFp_simple_point_copy, + ec_GFp_simple_point_set_to_infinity, + ec_GFp_simple_set_Jprojective_coordinates_GFp, + ec_GFp_simple_get_Jprojective_coordinates_GFp, + ec_GFp_simple_point_set_affine_coordinates, + ecp_nistz256_get_affine, + 0, 0, 0, + ec_GFp_simple_add, + ec_GFp_simple_dbl, + ec_GFp_simple_invert, + ec_GFp_simple_is_at_infinity, + ec_GFp_simple_is_on_curve, + ec_GFp_simple_cmp, + ec_GFp_simple_make_affine, + ec_GFp_simple_points_make_affine, + ecp_nistz256_points_mul, /* mul */ + ecp_nistz256_mult_precompute, /* precompute_mult */ + ecp_nistz256_window_have_precompute_mult, /* have_precompute_mult */ + ec_GFp_mont_field_mul, + ec_GFp_mont_field_sqr, + 0, /* field_div */ + ec_GFp_mont_field_encode, + ec_GFp_mont_field_decode, + ec_GFp_mont_field_set_to_one + }; + + return &ret; +} |