Merged origin/release (checked in because wanted to merge new stuff)

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;
+}