void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp)
{
    int i, j, max;
    const BN_ULONG *ap;
    BN_ULONG *rp;
    max = n * 2;
    ap = a;
    rp = r;
    rp[0] = rp[max - 1] = 0;
    rp++;
    j = n;
    if (--j > 0) {
        ap++;
        rp[j] = bn_mul_words(rp, ap, j, ap[-1]);
        rp += 2;
    }
    for (i = n - 2; i > 0; i--) {
        j--;
        ap++;
        rp[j] = bn_mul_add_words(rp, ap, j, ap[-1]);
        rp += 2;
    }
    bn_add_words(r, r, r, max);
    bn_sqr_words(tmp, a, n);
    bn_add_words(r, r, tmp, max);
}
['static int test_check_private_exponent(void)\n{\n    int ret = 0;\n    RSA *key = NULL;\n    BN_CTX *ctx = NULL;\n    BIGNUM *p = NULL, *q = NULL, *e = NULL, *d = NULL, *n = NULL;\n    ret = TEST_ptr(key = RSA_new())\n          && TEST_ptr(ctx = BN_CTX_new())\n          && TEST_ptr(p = BN_new())\n          && TEST_ptr(q = BN_new())\n          && TEST_true(BN_set_word(p, 15))\n          && TEST_true(BN_set_word(q, 17))\n          && TEST_true(RSA_set0_factors(key, p, q));\n    if (!ret) {\n        BN_free(p);\n        BN_free(q);\n        goto end;\n    }\n    ret = TEST_ptr(e = BN_new())\n          && TEST_ptr(d = BN_new())\n          && TEST_ptr(n = BN_new())\n          && TEST_true(BN_set_word(e, 5))\n          && TEST_true(BN_set_word(d, 157))\n          && TEST_true(BN_set_word(n, 15*17))\n          && TEST_true(RSA_set0_key(key, n, e, d));\n    if (!ret) {\n        BN_free(e);\n        BN_free(d);\n        BN_free(n);\n        goto end;\n    }\n    ret = TEST_false(rsa_check_private_exponent(key, 8, ctx))\n          && TEST_true(BN_set_word(d, 45))\n          && TEST_true(rsa_check_private_exponent(key, 8, ctx))\n          && TEST_false(rsa_check_private_exponent(key, 16, ctx))\n          && TEST_true(BN_set_word(d, 16))\n          && TEST_false(rsa_check_private_exponent(key, 8, ctx))\n          && TEST_true(BN_set_word(d, 46))\n          && TEST_false(rsa_check_private_exponent(key, 8, ctx));\nend:\n    RSA_free(key);\n    BN_CTX_free(ctx);\n    return ret;\n}', 'int BN_set_word(BIGNUM *a, BN_ULONG w)\n{\n    bn_check_top(a);\n    if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)\n        return 0;\n    a->neg = 0;\n    a->d[0] = w;\n    a->top = (w ? 1 : 0);\n    a->flags &= ~BN_FLG_FIXED_TOP;\n    bn_check_top(a);\n    return 1;\n}', 'int rsa_check_private_exponent(const RSA *rsa, int nbits, BN_CTX *ctx)\n{\n    int ret;\n    BIGNUM *r, *p1, *q1, *lcm, *p1q1, *gcd;\n    if (BN_num_bits(rsa->d) <= (nbits >> 1))\n        return 0;\n    BN_CTX_start(ctx);\n    r = BN_CTX_get(ctx);\n    p1 = BN_CTX_get(ctx);\n    q1 = BN_CTX_get(ctx);\n    lcm = BN_CTX_get(ctx);\n    p1q1 = BN_CTX_get(ctx);\n    gcd = BN_CTX_get(ctx);\n    ret = (gcd != NULL\n          && (rsa_get_lcm(ctx, rsa->p, rsa->q, lcm, gcd, p1, q1, p1q1) == 1)\n          && (BN_cmp(rsa->d, lcm) < 0)\n          && BN_mod_mul(r, rsa->e, rsa->d, lcm, ctx)\n          && BN_is_one(r));\n    BN_clear(p1);\n    BN_clear(q1);\n    BN_clear(lcm);\n    BN_clear(gcd);\n    BN_CTX_end(ctx);\n    return ret;\n}', 'int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,\n               BN_CTX *ctx)\n{\n    BIGNUM *t;\n    int ret = 0;\n    bn_check_top(a);\n    bn_check_top(b);\n    bn_check_top(m);\n    BN_CTX_start(ctx);\n    if ((t = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    if (a == b) {\n        if (!BN_sqr(t, a, ctx))\n            goto err;\n    } else {\n        if (!BN_mul(t, a, b, ctx))\n            goto err;\n    }\n    if (!BN_nnmod(r, t, m, ctx))\n        goto err;\n    bn_check_top(r);\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}', 'int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)\n{\n    int ret = bn_sqr_fixed_top(r, a, ctx);\n    bn_correct_top(r);\n    bn_check_top(r);\n    return ret;\n}', 'int bn_sqr_fixed_top(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)\n{\n    int max, al;\n    int ret = 0;\n    BIGNUM *tmp, *rr;\n    bn_check_top(a);\n    al = a->top;\n    if (al <= 0) {\n        r->top = 0;\n        r->neg = 0;\n        return 1;\n    }\n    BN_CTX_start(ctx);\n    rr = (a != r) ? r : BN_CTX_get(ctx);\n    tmp = BN_CTX_get(ctx);\n    if (rr == NULL || tmp == NULL)\n        goto err;\n    max = 2 * al;\n    if (bn_wexpand(rr, max) == NULL)\n        goto err;\n    if (al == 4) {\n#ifndef BN_SQR_COMBA\n        BN_ULONG t[8];\n        bn_sqr_normal(rr->d, a->d, 4, t);\n#else\n        bn_sqr_comba4(rr->d, a->d);\n#endif\n    } else if (al == 8) {\n#ifndef BN_SQR_COMBA\n        BN_ULONG t[16];\n        bn_sqr_normal(rr->d, a->d, 8, t);\n#else\n        bn_sqr_comba8(rr->d, a->d);\n#endif\n    } else {\n#if defined(BN_RECURSION)\n        if (al < BN_SQR_RECURSIVE_SIZE_NORMAL) {\n            BN_ULONG t[BN_SQR_RECURSIVE_SIZE_NORMAL * 2];\n            bn_sqr_normal(rr->d, a->d, al, t);\n        } else {\n            int j, k;\n            j = BN_num_bits_word((BN_ULONG)al);\n            j = 1 << (j - 1);\n            k = j + j;\n            if (al == j) {\n                if (bn_wexpand(tmp, k * 2) == NULL)\n                    goto err;\n                bn_sqr_recursive(rr->d, a->d, al, tmp->d);\n            } else {\n                if (bn_wexpand(tmp, max) == NULL)\n                    goto err;\n                bn_sqr_normal(rr->d, a->d, al, tmp->d);\n            }\n        }\n#else\n        if (bn_wexpand(tmp, max) == NULL)\n            goto err;\n        bn_sqr_normal(rr->d, a->d, al, tmp->d);\n#endif\n    }\n    rr->neg = 0;\n    rr->top = max;\n    rr->flags |= BN_FLG_FIXED_TOP;\n    if (r != rr && BN_copy(r, rr) == NULL)\n        goto err;\n    ret = 1;\n err:\n    bn_check_top(rr);\n    bn_check_top(tmp);\n    BN_CTX_end(ctx);\n    return ret;\n}', 'void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp)\n{\n    int i, j, max;\n    const BN_ULONG *ap;\n    BN_ULONG *rp;\n    max = n * 2;\n    ap = a;\n    rp = r;\n    rp[0] = rp[max - 1] = 0;\n    rp++;\n    j = n;\n    if (--j > 0) {\n        ap++;\n        rp[j] = bn_mul_words(rp, ap, j, ap[-1]);\n        rp += 2;\n    }\n    for (i = n - 2; i > 0; i--) {\n        j--;\n        ap++;\n        rp[j] = bn_mul_add_words(rp, ap, j, ap[-1]);\n        rp += 2;\n    }\n    bn_add_words(r, r, r, max);\n    bn_sqr_words(tmp, a, n);\n    bn_add_words(r, r, tmp, max);\n}']