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;
}
['int BN_GF2m_mod_inv(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx)\n{\n    BIGNUM *b = NULL;\n    int ret = 0;\n    BN_CTX_start(ctx);\n    if ((b = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    do {\n        if (!BN_priv_rand(b, BN_num_bits(p) - 1,\n                          BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY))\n            goto err;\n    } while (BN_is_zero(b));\n    if (!BN_GF2m_mod_mul(r, a, b, p, ctx))\n        goto err;\n    if (!BN_GF2m_mod_inv_vartime(r, r, p, ctx))\n        goto err;\n    if (!BN_GF2m_mod_mul(r, r, b, p, ctx))\n        goto err;\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}', 'int BN_priv_rand(BIGNUM *rnd, int bits, int top, int bottom)\n{\n    return bnrand(PRIVATE, rnd, bits, top, bottom, NULL);\n}', 'static int bnrand(BNRAND_FLAG flag, BIGNUM *rnd, int bits, int top, int bottom,\n                  BN_CTX *ctx)\n{\n    unsigned char *buf = NULL;\n    int b, ret = 0, bit, bytes, mask;\n    OPENSSL_CTX *libctx = bn_get_lib_ctx(ctx);\n    if (bits == 0) {\n        if (top != BN_RAND_TOP_ANY || bottom != BN_RAND_BOTTOM_ANY)\n            goto toosmall;\n        BN_zero(rnd);\n        return 1;\n    }\n    if (bits < 0 || (bits == 1 && top > 0))\n        goto toosmall;\n    bytes = (bits + 7) / 8;\n    bit = (bits - 1) % 8;\n    mask = 0xff << (bit + 1);\n    buf = OPENSSL_malloc(bytes);\n    if (buf == NULL) {\n        BNerr(BN_F_BNRAND, ERR_R_MALLOC_FAILURE);\n        goto err;\n    }\n    b = flag == NORMAL ? rand_bytes_ex(libctx, buf, bytes)\n                       : rand_priv_bytes_ex(libctx, buf, bytes);\n    if (b <= 0)\n        goto err;\n    if (flag == TESTING) {\n        int i;\n        unsigned char c;\n        for (i = 0; i < bytes; i++) {\n            if (rand_bytes_ex(libctx, &c, 1) <= 0)\n                goto err;\n            if (c >= 128 && i > 0)\n                buf[i] = buf[i - 1];\n            else if (c < 42)\n                buf[i] = 0;\n            else if (c < 84)\n                buf[i] = 255;\n        }\n    }\n    if (top >= 0) {\n        if (top) {\n            if (bit == 0) {\n                buf[0] = 1;\n                buf[1] |= 0x80;\n            } else {\n                buf[0] |= (3 << (bit - 1));\n            }\n        } else {\n            buf[0] |= (1 << bit);\n        }\n    }\n    buf[0] &= ~mask;\n    if (bottom)\n        buf[bytes - 1] |= 1;\n    if (!BN_bin2bn(buf, bytes, rnd))\n        goto err;\n    ret = 1;\n err:\n    OPENSSL_clear_free(buf, bytes);\n    bn_check_top(rnd);\n    return ret;\ntoosmall:\n    BNerr(BN_F_BNRAND, BN_R_BITS_TOO_SMALL);\n    return 0;\n}', 'int BN_GF2m_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,\n                    const BIGNUM *p, BN_CTX *ctx)\n{\n    int ret = 0;\n    const int max = BN_num_bits(p) + 1;\n    int *arr = NULL;\n    bn_check_top(a);\n    bn_check_top(b);\n    bn_check_top(p);\n    if ((arr = OPENSSL_malloc(sizeof(*arr) * max)) == NULL)\n        goto err;\n    ret = BN_GF2m_poly2arr(p, arr, max);\n    if (!ret || ret > max) {\n        BNerr(BN_F_BN_GF2M_MOD_MUL, BN_R_INVALID_LENGTH);\n        goto err;\n    }\n    ret = BN_GF2m_mod_mul_arr(r, a, b, arr, ctx);\n    bn_check_top(r);\n err:\n    OPENSSL_free(arr);\n    return ret;\n}', 'int BN_GF2m_mod_mul_arr(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,\n                        const int p[], BN_CTX *ctx)\n{\n    int zlen, i, j, k, ret = 0;\n    BIGNUM *s;\n    BN_ULONG x1, x0, y1, y0, zz[4];\n    bn_check_top(a);\n    bn_check_top(b);\n    if (a == b) {\n        return BN_GF2m_mod_sqr_arr(r, a, p, ctx);\n    }\n    BN_CTX_start(ctx);\n    if ((s = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    zlen = a->top + b->top + 4;\n    if (!bn_wexpand(s, zlen))\n        goto err;\n    s->top = zlen;\n    for (i = 0; i < zlen; i++)\n        s->d[i] = 0;\n    for (j = 0; j < b->top; j += 2) {\n        y0 = b->d[j];\n        y1 = ((j + 1) == b->top) ? 0 : b->d[j + 1];\n        for (i = 0; i < a->top; i += 2) {\n            x0 = a->d[i];\n            x1 = ((i + 1) == a->top) ? 0 : a->d[i + 1];\n            bn_GF2m_mul_2x2(zz, x1, x0, y1, y0);\n            for (k = 0; k < 4; k++)\n                s->d[i + j + k] ^= zz[k];\n        }\n    }\n    bn_correct_top(s);\n    if (BN_GF2m_mod_arr(r, s, p))\n        ret = 1;\n    bn_check_top(r);\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}']