zte's code,first commit

Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/lib/libssl/openssl-1.1.1o/crypto/bn/bn_gf2m.c b/ap/lib/libssl/openssl-1.1.1o/crypto/bn/bn_gf2m.c
new file mode 100644
index 0000000..a2ea867
--- /dev/null
+++ b/ap/lib/libssl/openssl-1.1.1o/crypto/bn/bn_gf2m.c
@@ -0,0 +1,1166 @@
+/*
+ * Copyright 2002-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <assert.h>
+#include <limits.h>
+#include <stdio.h>
+#include "internal/cryptlib.h"
+#include "bn_local.h"
+
+#ifndef OPENSSL_NO_EC2M
+
+/*
+ * Maximum number of iterations before BN_GF2m_mod_solve_quad_arr should
+ * fail.
+ */
+# define MAX_ITERATIONS 50
+
+# define SQR_nibble(w)   ((((w) & 8) << 3) \
+                       |  (((w) & 4) << 2) \
+                       |  (((w) & 2) << 1) \
+                       |   ((w) & 1))
+
+
+/* Platform-specific macros to accelerate squaring. */
+# if defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
+#  define SQR1(w) \
+    SQR_nibble((w) >> 60) << 56 | SQR_nibble((w) >> 56) << 48 | \
+    SQR_nibble((w) >> 52) << 40 | SQR_nibble((w) >> 48) << 32 | \
+    SQR_nibble((w) >> 44) << 24 | SQR_nibble((w) >> 40) << 16 | \
+    SQR_nibble((w) >> 36) <<  8 | SQR_nibble((w) >> 32)
+#  define SQR0(w) \
+    SQR_nibble((w) >> 28) << 56 | SQR_nibble((w) >> 24) << 48 | \
+    SQR_nibble((w) >> 20) << 40 | SQR_nibble((w) >> 16) << 32 | \
+    SQR_nibble((w) >> 12) << 24 | SQR_nibble((w) >>  8) << 16 | \
+    SQR_nibble((w) >>  4) <<  8 | SQR_nibble((w)      )
+# endif
+# ifdef THIRTY_TWO_BIT
+#  define SQR1(w) \
+    SQR_nibble((w) >> 28) << 24 | SQR_nibble((w) >> 24) << 16 | \
+    SQR_nibble((w) >> 20) <<  8 | SQR_nibble((w) >> 16)
+#  define SQR0(w) \
+    SQR_nibble((w) >> 12) << 24 | SQR_nibble((w) >>  8) << 16 | \
+    SQR_nibble((w) >>  4) <<  8 | SQR_nibble((w)      )
+# endif
+
+# if !defined(OPENSSL_BN_ASM_GF2m)
+/*
+ * Product of two polynomials a, b each with degree < BN_BITS2 - 1, result is
+ * a polynomial r with degree < 2 * BN_BITS - 1 The caller MUST ensure that
+ * the variables have the right amount of space allocated.
+ */
+#  ifdef THIRTY_TWO_BIT
+static void bn_GF2m_mul_1x1(BN_ULONG *r1, BN_ULONG *r0, const BN_ULONG a,
+                            const BN_ULONG b)
+{
+    register BN_ULONG h, l, s;
+    BN_ULONG tab[8], top2b = a >> 30;
+    register BN_ULONG a1, a2, a4;
+
+    a1 = a & (0x3FFFFFFF);
+    a2 = a1 << 1;
+    a4 = a2 << 1;
+
+    tab[0] = 0;
+    tab[1] = a1;
+    tab[2] = a2;
+    tab[3] = a1 ^ a2;
+    tab[4] = a4;
+    tab[5] = a1 ^ a4;
+    tab[6] = a2 ^ a4;
+    tab[7] = a1 ^ a2 ^ a4;
+
+    s = tab[b & 0x7];
+    l = s;
+    s = tab[b >> 3 & 0x7];
+    l ^= s << 3;
+    h = s >> 29;
+    s = tab[b >> 6 & 0x7];
+    l ^= s << 6;
+    h ^= s >> 26;
+    s = tab[b >> 9 & 0x7];
+    l ^= s << 9;
+    h ^= s >> 23;
+    s = tab[b >> 12 & 0x7];
+    l ^= s << 12;
+    h ^= s >> 20;
+    s = tab[b >> 15 & 0x7];
+    l ^= s << 15;
+    h ^= s >> 17;
+    s = tab[b >> 18 & 0x7];
+    l ^= s << 18;
+    h ^= s >> 14;
+    s = tab[b >> 21 & 0x7];
+    l ^= s << 21;
+    h ^= s >> 11;
+    s = tab[b >> 24 & 0x7];
+    l ^= s << 24;
+    h ^= s >> 8;
+    s = tab[b >> 27 & 0x7];
+    l ^= s << 27;
+    h ^= s >> 5;
+    s = tab[b >> 30];
+    l ^= s << 30;
+    h ^= s >> 2;
+
+    /* compensate for the top two bits of a */
+
+    if (top2b & 01) {
+        l ^= b << 30;
+        h ^= b >> 2;
+    }
+    if (top2b & 02) {
+        l ^= b << 31;
+        h ^= b >> 1;
+    }
+
+    *r1 = h;
+    *r0 = l;
+}
+#  endif
+#  if defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
+static void bn_GF2m_mul_1x1(BN_ULONG *r1, BN_ULONG *r0, const BN_ULONG a,
+                            const BN_ULONG b)
+{
+    register BN_ULONG h, l, s;
+    BN_ULONG tab[16], top3b = a >> 61;
+    register BN_ULONG a1, a2, a4, a8;
+
+    a1 = a & (0x1FFFFFFFFFFFFFFFULL);
+    a2 = a1 << 1;
+    a4 = a2 << 1;
+    a8 = a4 << 1;
+
+    tab[0] = 0;
+    tab[1] = a1;
+    tab[2] = a2;
+    tab[3] = a1 ^ a2;
+    tab[4] = a4;
+    tab[5] = a1 ^ a4;
+    tab[6] = a2 ^ a4;
+    tab[7] = a1 ^ a2 ^ a4;
+    tab[8] = a8;
+    tab[9] = a1 ^ a8;
+    tab[10] = a2 ^ a8;
+    tab[11] = a1 ^ a2 ^ a8;
+    tab[12] = a4 ^ a8;
+    tab[13] = a1 ^ a4 ^ a8;
+    tab[14] = a2 ^ a4 ^ a8;
+    tab[15] = a1 ^ a2 ^ a4 ^ a8;
+
+    s = tab[b & 0xF];
+    l = s;
+    s = tab[b >> 4 & 0xF];
+    l ^= s << 4;
+    h = s >> 60;
+    s = tab[b >> 8 & 0xF];
+    l ^= s << 8;
+    h ^= s >> 56;
+    s = tab[b >> 12 & 0xF];
+    l ^= s << 12;
+    h ^= s >> 52;
+    s = tab[b >> 16 & 0xF];
+    l ^= s << 16;
+    h ^= s >> 48;
+    s = tab[b >> 20 & 0xF];
+    l ^= s << 20;
+    h ^= s >> 44;
+    s = tab[b >> 24 & 0xF];
+    l ^= s << 24;
+    h ^= s >> 40;
+    s = tab[b >> 28 & 0xF];
+    l ^= s << 28;
+    h ^= s >> 36;
+    s = tab[b >> 32 & 0xF];
+    l ^= s << 32;
+    h ^= s >> 32;
+    s = tab[b >> 36 & 0xF];
+    l ^= s << 36;
+    h ^= s >> 28;
+    s = tab[b >> 40 & 0xF];
+    l ^= s << 40;
+    h ^= s >> 24;
+    s = tab[b >> 44 & 0xF];
+    l ^= s << 44;
+    h ^= s >> 20;
+    s = tab[b >> 48 & 0xF];
+    l ^= s << 48;
+    h ^= s >> 16;
+    s = tab[b >> 52 & 0xF];
+    l ^= s << 52;
+    h ^= s >> 12;
+    s = tab[b >> 56 & 0xF];
+    l ^= s << 56;
+    h ^= s >> 8;
+    s = tab[b >> 60];
+    l ^= s << 60;
+    h ^= s >> 4;
+
+    /* compensate for the top three bits of a */
+
+    if (top3b & 01) {
+        l ^= b << 61;
+        h ^= b >> 3;
+    }
+    if (top3b & 02) {
+        l ^= b << 62;
+        h ^= b >> 2;
+    }
+    if (top3b & 04) {
+        l ^= b << 63;
+        h ^= b >> 1;
+    }
+
+    *r1 = h;
+    *r0 = l;
+}
+#  endif
+
+/*
+ * Product of two polynomials a, b each with degree < 2 * BN_BITS2 - 1,
+ * result is a polynomial r with degree < 4 * BN_BITS2 - 1 The caller MUST
+ * ensure that the variables have the right amount of space allocated.
+ */
+static void bn_GF2m_mul_2x2(BN_ULONG *r, const BN_ULONG a1, const BN_ULONG a0,
+                            const BN_ULONG b1, const BN_ULONG b0)
+{
+    BN_ULONG m1, m0;
+    /* r[3] = h1, r[2] = h0; r[1] = l1; r[0] = l0 */
+    bn_GF2m_mul_1x1(r + 3, r + 2, a1, b1);
+    bn_GF2m_mul_1x1(r + 1, r, a0, b0);
+    bn_GF2m_mul_1x1(&m1, &m0, a0 ^ a1, b0 ^ b1);
+    /* Correction on m1 ^= l1 ^ h1; m0 ^= l0 ^ h0; */
+    r[2] ^= m1 ^ r[1] ^ r[3];   /* h0 ^= m1 ^ l1 ^ h1; */
+    r[1] = r[3] ^ r[2] ^ r[0] ^ m1 ^ m0; /* l1 ^= l0 ^ h0 ^ m0; */
+}
+# else
+void bn_GF2m_mul_2x2(BN_ULONG *r, BN_ULONG a1, BN_ULONG a0, BN_ULONG b1,
+                     BN_ULONG b0);
+# endif
+
+/*
+ * Add polynomials a and b and store result in r; r could be a or b, a and b
+ * could be equal; r is the bitwise XOR of a and b.
+ */
+int BN_GF2m_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
+{
+    int i;
+    const BIGNUM *at, *bt;
+
+    bn_check_top(a);
+    bn_check_top(b);
+
+    if (a->top < b->top) {
+        at = b;
+        bt = a;
+    } else {
+        at = a;
+        bt = b;
+    }
+
+    if (bn_wexpand(r, at->top) == NULL)
+        return 0;
+
+    for (i = 0; i < bt->top; i++) {
+        r->d[i] = at->d[i] ^ bt->d[i];
+    }
+    for (; i < at->top; i++) {
+        r->d[i] = at->d[i];
+    }
+
+    r->top = at->top;
+    bn_correct_top(r);
+
+    return 1;
+}
+
+/*-
+ * Some functions allow for representation of the irreducible polynomials
+ * as an int[], say p.  The irreducible f(t) is then of the form:
+ *     t^p[0] + t^p[1] + ... + t^p[k]
+ * where m = p[0] > p[1] > ... > p[k] = 0.
+ */
+
+/* Performs modular reduction of a and store result in r.  r could be a. */
+int BN_GF2m_mod_arr(BIGNUM *r, const BIGNUM *a, const int p[])
+{
+    int j, k;
+    int n, dN, d0, d1;
+    BN_ULONG zz, *z;
+
+    bn_check_top(a);
+
+    if (!p[0]) {
+        /* reduction mod 1 => return 0 */
+        BN_zero(r);
+        return 1;
+    }
+
+    /*
+     * Since the algorithm does reduction in the r value, if a != r, copy the
+     * contents of a into r so we can do reduction in r.
+     */
+    if (a != r) {
+        if (!bn_wexpand(r, a->top))
+            return 0;
+        for (j = 0; j < a->top; j++) {
+            r->d[j] = a->d[j];
+        }
+        r->top = a->top;
+    }
+    z = r->d;
+
+    /* start reduction */
+    dN = p[0] / BN_BITS2;
+    for (j = r->top - 1; j > dN;) {
+        zz = z[j];
+        if (z[j] == 0) {
+            j--;
+            continue;
+        }
+        z[j] = 0;
+
+        for (k = 1; p[k] != 0; k++) {
+            /* reducing component t^p[k] */
+            n = p[0] - p[k];
+            d0 = n % BN_BITS2;
+            d1 = BN_BITS2 - d0;
+            n /= BN_BITS2;
+            z[j - n] ^= (zz >> d0);
+            if (d0)
+                z[j - n - 1] ^= (zz << d1);
+        }
+
+        /* reducing component t^0 */
+        n = dN;
+        d0 = p[0] % BN_BITS2;
+        d1 = BN_BITS2 - d0;
+        z[j - n] ^= (zz >> d0);
+        if (d0)
+            z[j - n - 1] ^= (zz << d1);
+    }
+
+    /* final round of reduction */
+    while (j == dN) {
+
+        d0 = p[0] % BN_BITS2;
+        zz = z[dN] >> d0;
+        if (zz == 0)
+            break;
+        d1 = BN_BITS2 - d0;
+
+        /* clear up the top d1 bits */
+        if (d0)
+            z[dN] = (z[dN] << d1) >> d1;
+        else
+            z[dN] = 0;
+        z[0] ^= zz;             /* reduction t^0 component */
+
+        for (k = 1; p[k] != 0; k++) {
+            BN_ULONG tmp_ulong;
+
+            /* reducing component t^p[k] */
+            n = p[k] / BN_BITS2;
+            d0 = p[k] % BN_BITS2;
+            d1 = BN_BITS2 - d0;
+            z[n] ^= (zz << d0);
+            if (d0 && (tmp_ulong = zz >> d1))
+                z[n + 1] ^= tmp_ulong;
+        }
+
+    }
+
+    bn_correct_top(r);
+    return 1;
+}
+
+/*
+ * Performs modular reduction of a by p and store result in r.  r could be a.
+ * This function calls down to the BN_GF2m_mod_arr implementation; this wrapper
+ * function is only provided for convenience; for best performance, use the
+ * BN_GF2m_mod_arr function.
+ */
+int BN_GF2m_mod(BIGNUM *r, const BIGNUM *a, const BIGNUM *p)
+{
+    int ret = 0;
+    int arr[6];
+    bn_check_top(a);
+    bn_check_top(p);
+    ret = BN_GF2m_poly2arr(p, arr, OSSL_NELEM(arr));
+    if (!ret || ret > (int)OSSL_NELEM(arr)) {
+        BNerr(BN_F_BN_GF2M_MOD, BN_R_INVALID_LENGTH);
+        return 0;
+    }
+    ret = BN_GF2m_mod_arr(r, a, arr);
+    bn_check_top(r);
+    return ret;
+}
+
+/*
+ * Compute the product of two polynomials a and b, reduce modulo p, and store
+ * the result in r.  r could be a or b; a could be b.
+ */
+int BN_GF2m_mod_mul_arr(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
+                        const int p[], BN_CTX *ctx)
+{
+    int zlen, i, j, k, ret = 0;
+    BIGNUM *s;
+    BN_ULONG x1, x0, y1, y0, zz[4];
+
+    bn_check_top(a);
+    bn_check_top(b);
+
+    if (a == b) {
+        return BN_GF2m_mod_sqr_arr(r, a, p, ctx);
+    }
+
+    BN_CTX_start(ctx);
+    if ((s = BN_CTX_get(ctx)) == NULL)
+        goto err;
+
+    zlen = a->top + b->top + 4;
+    if (!bn_wexpand(s, zlen))
+        goto err;
+    s->top = zlen;
+
+    for (i = 0; i < zlen; i++)
+        s->d[i] = 0;
+
+    for (j = 0; j < b->top; j += 2) {
+        y0 = b->d[j];
+        y1 = ((j + 1) == b->top) ? 0 : b->d[j + 1];
+        for (i = 0; i < a->top; i += 2) {
+            x0 = a->d[i];
+            x1 = ((i + 1) == a->top) ? 0 : a->d[i + 1];
+            bn_GF2m_mul_2x2(zz, x1, x0, y1, y0);
+            for (k = 0; k < 4; k++)
+                s->d[i + j + k] ^= zz[k];
+        }
+    }
+
+    bn_correct_top(s);
+    if (BN_GF2m_mod_arr(r, s, p))
+        ret = 1;
+    bn_check_top(r);
+
+ err:
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+/*
+ * Compute the product of two polynomials a and b, reduce modulo p, and store
+ * the result in r.  r could be a or b; a could equal b. This function calls
+ * down to the BN_GF2m_mod_mul_arr implementation; this wrapper function is
+ * only provided for convenience; for best performance, use the
+ * BN_GF2m_mod_mul_arr function.
+ */
+int BN_GF2m_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
+                    const BIGNUM *p, BN_CTX *ctx)
+{
+    int ret = 0;
+    const int max = BN_num_bits(p) + 1;
+    int *arr = NULL;
+    bn_check_top(a);
+    bn_check_top(b);
+    bn_check_top(p);
+    if ((arr = OPENSSL_malloc(sizeof(*arr) * max)) == NULL)
+        goto err;
+    ret = BN_GF2m_poly2arr(p, arr, max);
+    if (!ret || ret > max) {
+        BNerr(BN_F_BN_GF2M_MOD_MUL, BN_R_INVALID_LENGTH);
+        goto err;
+    }
+    ret = BN_GF2m_mod_mul_arr(r, a, b, arr, ctx);
+    bn_check_top(r);
+ err:
+    OPENSSL_free(arr);
+    return ret;
+}
+
+/* Square a, reduce the result mod p, and store it in a.  r could be a. */
+int BN_GF2m_mod_sqr_arr(BIGNUM *r, const BIGNUM *a, const int p[],
+                        BN_CTX *ctx)
+{
+    int i, ret = 0;
+    BIGNUM *s;
+
+    bn_check_top(a);
+    BN_CTX_start(ctx);
+    if ((s = BN_CTX_get(ctx)) == NULL)
+        goto err;
+    if (!bn_wexpand(s, 2 * a->top))
+        goto err;
+
+    for (i = a->top - 1; i >= 0; i--) {
+        s->d[2 * i + 1] = SQR1(a->d[i]);
+        s->d[2 * i] = SQR0(a->d[i]);
+    }
+
+    s->top = 2 * a->top;
+    bn_correct_top(s);
+    if (!BN_GF2m_mod_arr(r, s, p))
+        goto err;
+    bn_check_top(r);
+    ret = 1;
+ err:
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+/*
+ * Square a, reduce the result mod p, and store it in a.  r could be a. This
+ * function calls down to the BN_GF2m_mod_sqr_arr implementation; this
+ * wrapper function is only provided for convenience; for best performance,
+ * use the BN_GF2m_mod_sqr_arr function.
+ */
+int BN_GF2m_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
+{
+    int ret = 0;
+    const int max = BN_num_bits(p) + 1;
+    int *arr = NULL;
+
+    bn_check_top(a);
+    bn_check_top(p);
+    if ((arr = OPENSSL_malloc(sizeof(*arr) * max)) == NULL)
+        goto err;
+    ret = BN_GF2m_poly2arr(p, arr, max);
+    if (!ret || ret > max) {
+        BNerr(BN_F_BN_GF2M_MOD_SQR, BN_R_INVALID_LENGTH);
+        goto err;
+    }
+    ret = BN_GF2m_mod_sqr_arr(r, a, arr, ctx);
+    bn_check_top(r);
+ err:
+    OPENSSL_free(arr);
+    return ret;
+}
+
+/*
+ * Invert a, reduce modulo p, and store the result in r. r could be a. Uses
+ * Modified Almost Inverse Algorithm (Algorithm 10) from Hankerson, D.,
+ * Hernandez, J.L., and Menezes, A.  "Software Implementation of Elliptic
+ * Curve Cryptography Over Binary Fields".
+ */
+static int BN_GF2m_mod_inv_vartime(BIGNUM *r, const BIGNUM *a,
+                                   const BIGNUM *p, BN_CTX *ctx)
+{
+    BIGNUM *b, *c = NULL, *u = NULL, *v = NULL, *tmp;
+    int ret = 0;
+
+    bn_check_top(a);
+    bn_check_top(p);
+
+    BN_CTX_start(ctx);
+
+    b = BN_CTX_get(ctx);
+    c = BN_CTX_get(ctx);
+    u = BN_CTX_get(ctx);
+    v = BN_CTX_get(ctx);
+    if (v == NULL)
+        goto err;
+
+    if (!BN_GF2m_mod(u, a, p))
+        goto err;
+    if (BN_is_zero(u))
+        goto err;
+
+    if (!BN_copy(v, p))
+        goto err;
+# if 0
+    if (!BN_one(b))
+        goto err;
+
+    while (1) {
+        while (!BN_is_odd(u)) {
+            if (BN_is_zero(u))
+                goto err;
+            if (!BN_rshift1(u, u))
+                goto err;
+            if (BN_is_odd(b)) {
+                if (!BN_GF2m_add(b, b, p))
+                    goto err;
+            }
+            if (!BN_rshift1(b, b))
+                goto err;
+        }
+
+        if (BN_abs_is_word(u, 1))
+            break;
+
+        if (BN_num_bits(u) < BN_num_bits(v)) {
+            tmp = u;
+            u = v;
+            v = tmp;
+            tmp = b;
+            b = c;
+            c = tmp;
+        }
+
+        if (!BN_GF2m_add(u, u, v))
+            goto err;
+        if (!BN_GF2m_add(b, b, c))
+            goto err;
+    }
+# else
+    {
+        int i;
+        int ubits = BN_num_bits(u);
+        int vbits = BN_num_bits(v); /* v is copy of p */
+        int top = p->top;
+        BN_ULONG *udp, *bdp, *vdp, *cdp;
+
+        if (!bn_wexpand(u, top))
+            goto err;
+        udp = u->d;
+        for (i = u->top; i < top; i++)
+            udp[i] = 0;
+        u->top = top;
+        if (!bn_wexpand(b, top))
+          goto err;
+        bdp = b->d;
+        bdp[0] = 1;
+        for (i = 1; i < top; i++)
+            bdp[i] = 0;
+        b->top = top;
+        if (!bn_wexpand(c, top))
+          goto err;
+        cdp = c->d;
+        for (i = 0; i < top; i++)
+            cdp[i] = 0;
+        c->top = top;
+        vdp = v->d;             /* It pays off to "cache" *->d pointers,
+                                 * because it allows optimizer to be more
+                                 * aggressive. But we don't have to "cache"
+                                 * p->d, because *p is declared 'const'... */
+        while (1) {
+            while (ubits && !(udp[0] & 1)) {
+                BN_ULONG u0, u1, b0, b1, mask;
+
+                u0 = udp[0];
+                b0 = bdp[0];
+                mask = (BN_ULONG)0 - (b0 & 1);
+                b0 ^= p->d[0] & mask;
+                for (i = 0; i < top - 1; i++) {
+                    u1 = udp[i + 1];
+                    udp[i] = ((u0 >> 1) | (u1 << (BN_BITS2 - 1))) & BN_MASK2;
+                    u0 = u1;
+                    b1 = bdp[i + 1] ^ (p->d[i + 1] & mask);
+                    bdp[i] = ((b0 >> 1) | (b1 << (BN_BITS2 - 1))) & BN_MASK2;
+                    b0 = b1;
+                }
+                udp[i] = u0 >> 1;
+                bdp[i] = b0 >> 1;
+                ubits--;
+            }
+
+            if (ubits <= BN_BITS2) {
+                if (udp[0] == 0) /* poly was reducible */
+                    goto err;
+                if (udp[0] == 1)
+                    break;
+            }
+
+            if (ubits < vbits) {
+                i = ubits;
+                ubits = vbits;
+                vbits = i;
+                tmp = u;
+                u = v;
+                v = tmp;
+                tmp = b;
+                b = c;
+                c = tmp;
+                udp = vdp;
+                vdp = v->d;
+                bdp = cdp;
+                cdp = c->d;
+            }
+            for (i = 0; i < top; i++) {
+                udp[i] ^= vdp[i];
+                bdp[i] ^= cdp[i];
+            }
+            if (ubits == vbits) {
+                BN_ULONG ul;
+                int utop = (ubits - 1) / BN_BITS2;
+
+                while ((ul = udp[utop]) == 0 && utop)
+                    utop--;
+                ubits = utop * BN_BITS2 + BN_num_bits_word(ul);
+            }
+        }
+        bn_correct_top(b);
+    }
+# endif
+
+    if (!BN_copy(r, b))
+        goto err;
+    bn_check_top(r);
+    ret = 1;
+
+ err:
+# ifdef BN_DEBUG                /* BN_CTX_end would complain about the
+                                 * expanded form */
+    bn_correct_top(c);
+    bn_correct_top(u);
+    bn_correct_top(v);
+# endif
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+/*-
+ * Wrapper for BN_GF2m_mod_inv_vartime that blinds the input before calling.
+ * This is not constant time.
+ * But it does eliminate first order deduction on the input.
+ */
+int BN_GF2m_mod_inv(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
+{
+    BIGNUM *b = NULL;
+    int ret = 0;
+
+    BN_CTX_start(ctx);
+    if ((b = BN_CTX_get(ctx)) == NULL)
+        goto err;
+
+    /* generate blinding value */
+    do {
+        if (!BN_priv_rand(b, BN_num_bits(p) - 1,
+                          BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY))
+            goto err;
+    } while (BN_is_zero(b));
+
+    /* r := a * b */
+    if (!BN_GF2m_mod_mul(r, a, b, p, ctx))
+        goto err;
+
+    /* r := 1/(a * b) */
+    if (!BN_GF2m_mod_inv_vartime(r, r, p, ctx))
+        goto err;
+
+    /* r := b/(a * b) = 1/a */
+    if (!BN_GF2m_mod_mul(r, r, b, p, ctx))
+        goto err;
+
+    ret = 1;
+
+ err:
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+/*
+ * Invert xx, reduce modulo p, and store the result in r. r could be xx.
+ * This function calls down to the BN_GF2m_mod_inv implementation; this
+ * wrapper function is only provided for convenience; for best performance,
+ * use the BN_GF2m_mod_inv function.
+ */
+int BN_GF2m_mod_inv_arr(BIGNUM *r, const BIGNUM *xx, const int p[],
+                        BN_CTX *ctx)
+{
+    BIGNUM *field;
+    int ret = 0;
+
+    bn_check_top(xx);
+    BN_CTX_start(ctx);
+    if ((field = BN_CTX_get(ctx)) == NULL)
+        goto err;
+    if (!BN_GF2m_arr2poly(p, field))
+        goto err;
+
+    ret = BN_GF2m_mod_inv(r, xx, field, ctx);
+    bn_check_top(r);
+
+ err:
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+/*
+ * Divide y by x, reduce modulo p, and store the result in r. r could be x
+ * or y, x could equal y.
+ */
+int BN_GF2m_mod_div(BIGNUM *r, const BIGNUM *y, const BIGNUM *x,
+                    const BIGNUM *p, BN_CTX *ctx)
+{
+    BIGNUM *xinv = NULL;
+    int ret = 0;
+
+    bn_check_top(y);
+    bn_check_top(x);
+    bn_check_top(p);
+
+    BN_CTX_start(ctx);
+    xinv = BN_CTX_get(ctx);
+    if (xinv == NULL)
+        goto err;
+
+    if (!BN_GF2m_mod_inv(xinv, x, p, ctx))
+        goto err;
+    if (!BN_GF2m_mod_mul(r, y, xinv, p, ctx))
+        goto err;
+    bn_check_top(r);
+    ret = 1;
+
+ err:
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+/*
+ * Divide yy by xx, reduce modulo p, and store the result in r. r could be xx
+ * * or yy, xx could equal yy. This function calls down to the
+ * BN_GF2m_mod_div implementation; this wrapper function is only provided for
+ * convenience; for best performance, use the BN_GF2m_mod_div function.
+ */
+int BN_GF2m_mod_div_arr(BIGNUM *r, const BIGNUM *yy, const BIGNUM *xx,
+                        const int p[], BN_CTX *ctx)
+{
+    BIGNUM *field;
+    int ret = 0;
+
+    bn_check_top(yy);
+    bn_check_top(xx);
+
+    BN_CTX_start(ctx);
+    if ((field = BN_CTX_get(ctx)) == NULL)
+        goto err;
+    if (!BN_GF2m_arr2poly(p, field))
+        goto err;
+
+    ret = BN_GF2m_mod_div(r, yy, xx, field, ctx);
+    bn_check_top(r);
+
+ err:
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+/*
+ * Compute the bth power of a, reduce modulo p, and store the result in r.  r
+ * could be a. Uses simple square-and-multiply algorithm A.5.1 from IEEE
+ * P1363.
+ */
+int BN_GF2m_mod_exp_arr(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
+                        const int p[], BN_CTX *ctx)
+{
+    int ret = 0, i, n;
+    BIGNUM *u;
+
+    bn_check_top(a);
+    bn_check_top(b);
+
+    if (BN_is_zero(b))
+        return BN_one(r);
+
+    if (BN_abs_is_word(b, 1))
+        return (BN_copy(r, a) != NULL);
+
+    BN_CTX_start(ctx);
+    if ((u = BN_CTX_get(ctx)) == NULL)
+        goto err;
+
+    if (!BN_GF2m_mod_arr(u, a, p))
+        goto err;
+
+    n = BN_num_bits(b) - 1;
+    for (i = n - 1; i >= 0; i--) {
+        if (!BN_GF2m_mod_sqr_arr(u, u, p, ctx))
+            goto err;
+        if (BN_is_bit_set(b, i)) {
+            if (!BN_GF2m_mod_mul_arr(u, u, a, p, ctx))
+                goto err;
+        }
+    }
+    if (!BN_copy(r, u))
+        goto err;
+    bn_check_top(r);
+    ret = 1;
+ err:
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+/*
+ * Compute the bth power of a, reduce modulo p, and store the result in r.  r
+ * could be a. This function calls down to the BN_GF2m_mod_exp_arr
+ * implementation; this wrapper function is only provided for convenience;
+ * for best performance, use the BN_GF2m_mod_exp_arr function.
+ */
+int BN_GF2m_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
+                    const BIGNUM *p, BN_CTX *ctx)
+{
+    int ret = 0;
+    const int max = BN_num_bits(p) + 1;
+    int *arr = NULL;
+    bn_check_top(a);
+    bn_check_top(b);
+    bn_check_top(p);
+    if ((arr = OPENSSL_malloc(sizeof(*arr) * max)) == NULL)
+        goto err;
+    ret = BN_GF2m_poly2arr(p, arr, max);
+    if (!ret || ret > max) {
+        BNerr(BN_F_BN_GF2M_MOD_EXP, BN_R_INVALID_LENGTH);
+        goto err;
+    }
+    ret = BN_GF2m_mod_exp_arr(r, a, b, arr, ctx);
+    bn_check_top(r);
+ err:
+    OPENSSL_free(arr);
+    return ret;
+}
+
+/*
+ * Compute the square root of a, reduce modulo p, and store the result in r.
+ * r could be a. Uses exponentiation as in algorithm A.4.1 from IEEE P1363.
+ */
+int BN_GF2m_mod_sqrt_arr(BIGNUM *r, const BIGNUM *a, const int p[],
+                         BN_CTX *ctx)
+{
+    int ret = 0;
+    BIGNUM *u;
+
+    bn_check_top(a);
+
+    if (!p[0]) {
+        /* reduction mod 1 => return 0 */
+        BN_zero(r);
+        return 1;
+    }
+
+    BN_CTX_start(ctx);
+    if ((u = BN_CTX_get(ctx)) == NULL)
+        goto err;
+
+    if (!BN_set_bit(u, p[0] - 1))
+        goto err;
+    ret = BN_GF2m_mod_exp_arr(r, a, u, p, ctx);
+    bn_check_top(r);
+
+ err:
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+/*
+ * Compute the square root of a, reduce modulo p, and store the result in r.
+ * r could be a. This function calls down to the BN_GF2m_mod_sqrt_arr
+ * implementation; this wrapper function is only provided for convenience;
+ * for best performance, use the BN_GF2m_mod_sqrt_arr function.
+ */
+int BN_GF2m_mod_sqrt(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)
+{
+    int ret = 0;
+    const int max = BN_num_bits(p) + 1;
+    int *arr = NULL;
+    bn_check_top(a);
+    bn_check_top(p);
+    if ((arr = OPENSSL_malloc(sizeof(*arr) * max)) == NULL)
+        goto err;
+    ret = BN_GF2m_poly2arr(p, arr, max);
+    if (!ret || ret > max) {
+        BNerr(BN_F_BN_GF2M_MOD_SQRT, BN_R_INVALID_LENGTH);
+        goto err;
+    }
+    ret = BN_GF2m_mod_sqrt_arr(r, a, arr, ctx);
+    bn_check_top(r);
+ err:
+    OPENSSL_free(arr);
+    return ret;
+}
+
+/*
+ * Find r such that r^2 + r = a mod p.  r could be a. If no r exists returns
+ * 0. Uses algorithms A.4.7 and A.4.6 from IEEE P1363.
+ */
+int BN_GF2m_mod_solve_quad_arr(BIGNUM *r, const BIGNUM *a_, const int p[],
+                               BN_CTX *ctx)
+{
+    int ret = 0, count = 0, j;
+    BIGNUM *a, *z, *rho, *w, *w2, *tmp;
+
+    bn_check_top(a_);
+
+    if (!p[0]) {
+        /* reduction mod 1 => return 0 */
+        BN_zero(r);
+        return 1;
+    }
+
+    BN_CTX_start(ctx);
+    a = BN_CTX_get(ctx);
+    z = BN_CTX_get(ctx);
+    w = BN_CTX_get(ctx);
+    if (w == NULL)
+        goto err;
+
+    if (!BN_GF2m_mod_arr(a, a_, p))
+        goto err;
+
+    if (BN_is_zero(a)) {
+        BN_zero(r);
+        ret = 1;
+        goto err;
+    }
+
+    if (p[0] & 0x1) {           /* m is odd */
+        /* compute half-trace of a */
+        if (!BN_copy(z, a))
+            goto err;
+        for (j = 1; j <= (p[0] - 1) / 2; j++) {
+            if (!BN_GF2m_mod_sqr_arr(z, z, p, ctx))
+                goto err;
+            if (!BN_GF2m_mod_sqr_arr(z, z, p, ctx))
+                goto err;
+            if (!BN_GF2m_add(z, z, a))
+                goto err;
+        }
+
+    } else {                    /* m is even */
+
+        rho = BN_CTX_get(ctx);
+        w2 = BN_CTX_get(ctx);
+        tmp = BN_CTX_get(ctx);
+        if (tmp == NULL)
+            goto err;
+        do {
+            if (!BN_priv_rand(rho, p[0], BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY))
+                goto err;
+            if (!BN_GF2m_mod_arr(rho, rho, p))
+                goto err;
+            BN_zero(z);
+            if (!BN_copy(w, rho))
+                goto err;
+            for (j = 1; j <= p[0] - 1; j++) {
+                if (!BN_GF2m_mod_sqr_arr(z, z, p, ctx))
+                    goto err;
+                if (!BN_GF2m_mod_sqr_arr(w2, w, p, ctx))
+                    goto err;
+                if (!BN_GF2m_mod_mul_arr(tmp, w2, a, p, ctx))
+                    goto err;
+                if (!BN_GF2m_add(z, z, tmp))
+                    goto err;
+                if (!BN_GF2m_add(w, w2, rho))
+                    goto err;
+            }
+            count++;
+        } while (BN_is_zero(w) && (count < MAX_ITERATIONS));
+        if (BN_is_zero(w)) {
+            BNerr(BN_F_BN_GF2M_MOD_SOLVE_QUAD_ARR, BN_R_TOO_MANY_ITERATIONS);
+            goto err;
+        }
+    }
+
+    if (!BN_GF2m_mod_sqr_arr(w, z, p, ctx))
+        goto err;
+    if (!BN_GF2m_add(w, z, w))
+        goto err;
+    if (BN_GF2m_cmp(w, a)) {
+        BNerr(BN_F_BN_GF2M_MOD_SOLVE_QUAD_ARR, BN_R_NO_SOLUTION);
+        goto err;
+    }
+
+    if (!BN_copy(r, z))
+        goto err;
+    bn_check_top(r);
+
+    ret = 1;
+
+ err:
+    BN_CTX_end(ctx);
+    return ret;
+}
+
+/*
+ * Find r such that r^2 + r = a mod p.  r could be a. If no r exists returns
+ * 0. This function calls down to the BN_GF2m_mod_solve_quad_arr
+ * implementation; this wrapper function is only provided for convenience;
+ * for best performance, use the BN_GF2m_mod_solve_quad_arr function.
+ */
+int BN_GF2m_mod_solve_quad(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
+                           BN_CTX *ctx)
+{
+    int ret = 0;
+    const int max = BN_num_bits(p) + 1;
+    int *arr = NULL;
+    bn_check_top(a);
+    bn_check_top(p);
+    if ((arr = OPENSSL_malloc(sizeof(*arr) * max)) == NULL)
+        goto err;
+    ret = BN_GF2m_poly2arr(p, arr, max);
+    if (!ret || ret > max) {
+        BNerr(BN_F_BN_GF2M_MOD_SOLVE_QUAD, BN_R_INVALID_LENGTH);
+        goto err;
+    }
+    ret = BN_GF2m_mod_solve_quad_arr(r, a, arr, ctx);
+    bn_check_top(r);
+ err:
+    OPENSSL_free(arr);
+    return ret;
+}
+
+/*
+ * Convert the bit-string representation of a polynomial ( \sum_{i=0}^n a_i *
+ * x^i) into an array of integers corresponding to the bits with non-zero
+ * coefficient.  Array is terminated with -1. Up to max elements of the array
+ * will be filled.  Return value is total number of array elements that would
+ * be filled if array was large enough.
+ */
+int BN_GF2m_poly2arr(const BIGNUM *a, int p[], int max)
+{
+    int i, j, k = 0;
+    BN_ULONG mask;
+
+    if (BN_is_zero(a))
+        return 0;
+
+    for (i = a->top - 1; i >= 0; i--) {
+        if (!a->d[i])
+            /* skip word if a->d[i] == 0 */
+            continue;
+        mask = BN_TBIT;
+        for (j = BN_BITS2 - 1; j >= 0; j--) {
+            if (a->d[i] & mask) {
+                if (k < max)
+                    p[k] = BN_BITS2 * i + j;
+                k++;
+            }
+            mask >>= 1;
+        }
+    }
+
+    if (k < max) {
+        p[k] = -1;
+        k++;
+    }
+
+    return k;
+}
+
+/*
+ * Convert the coefficient array representation of a polynomial to a
+ * bit-string.  The array must be terminated by -1.
+ */
+int BN_GF2m_arr2poly(const int p[], BIGNUM *a)
+{
+    int i;
+
+    bn_check_top(a);
+    BN_zero(a);
+    for (i = 0; p[i] != -1; i++) {
+        if (BN_set_bit(a, p[i]) == 0)
+            return 0;
+    }
+    bn_check_top(a);
+
+    return 1;
+}
+
+#endif