BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
{
    bn_check_top(b);
    if (a == b)
        return a;
    if (bn_wexpand(a, b->top) == NULL)
        return NULL;
    if (b->top > 0)
        memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
    a->top = b->top;
    a->neg = b->neg;
    bn_check_top(a);
    return a;
}
['static int srp_Verify_N_and_g(const BIGNUM *N, const BIGNUM *g)\n{\n    BN_CTX *bn_ctx = BN_CTX_new();\n    BIGNUM *p = BN_new();\n    BIGNUM *r = BN_new();\n    int ret =\n        g != NULL && N != NULL && bn_ctx != NULL && BN_is_odd(N) &&\n        BN_is_prime_ex(N, SRP_NUMBER_ITERATIONS_FOR_PRIME, bn_ctx, NULL) == 1 &&\n        p != NULL && BN_rshift1(p, N) &&\n        BN_is_prime_ex(p, SRP_NUMBER_ITERATIONS_FOR_PRIME, bn_ctx, NULL) == 1 &&\n        r != NULL &&\n        BN_mod_exp(r, g, p, N, bn_ctx) &&\n        BN_add_word(r, 1) && BN_cmp(r, N) == 0;\n    BN_free(r);\n    BN_free(p);\n    BN_CTX_free(bn_ctx);\n    return ret;\n}', 'int BN_is_odd(const BIGNUM *a)\n{\n    return (a->top > 0) && (a->d[0] & 1);\n}', 'int BN_is_prime_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,\n                   BN_GENCB *cb)\n{\n    return BN_is_prime_fasttest_ex(a, checks, ctx_passed, 0, cb);\n}', 'int BN_is_prime_fasttest_ex(const BIGNUM *a, int checks, BN_CTX *ctx_passed,\n                            int do_trial_division, BN_GENCB *cb)\n{\n    int i, j, ret = -1;\n    int k;\n    BN_CTX *ctx = NULL;\n    BIGNUM *A1, *A1_odd, *A3, *check;\n    BN_MONT_CTX *mont = NULL;\n    if (BN_is_word(a, 2) || BN_is_word(a, 3))\n        return 1;\n    if (!BN_is_odd(a) || BN_cmp(a, BN_value_one()) <= 0)\n        return 0;\n    if (checks == BN_prime_checks)\n        checks = BN_prime_checks_for_size(BN_num_bits(a));\n    if (do_trial_division) {\n        for (i = 1; i < NUMPRIMES; i++) {\n            BN_ULONG mod = BN_mod_word(a, primes[i]);\n            if (mod == (BN_ULONG)-1)\n                goto err;\n            if (mod == 0)\n                return BN_is_word(a, primes[i]);\n        }\n        if (!BN_GENCB_call(cb, 1, -1))\n            goto err;\n    }\n    if (ctx_passed != NULL)\n        ctx = ctx_passed;\n    else if ((ctx = BN_CTX_new()) == NULL)\n        goto err;\n    BN_CTX_start(ctx);\n    A1 = BN_CTX_get(ctx);\n    A3 = BN_CTX_get(ctx);\n    A1_odd = BN_CTX_get(ctx);\n    check = BN_CTX_get(ctx);\n    if (check == NULL)\n        goto err;\n    if (!BN_copy(A1, a) || !BN_sub_word(A1, 1))\n        goto err;\n    if (!BN_copy(A3, a) || !BN_sub_word(A3, 3))\n        goto err;\n    k = 1;\n    while (!BN_is_bit_set(A1, k))\n        k++;\n    if (!BN_rshift(A1_odd, A1, k))\n        goto err;\n    mont = BN_MONT_CTX_new();\n    if (mont == NULL)\n        goto err;\n    if (!BN_MONT_CTX_set(mont, a, ctx))\n        goto err;\n    for (i = 0; i < checks; i++) {\n        if (!BN_priv_rand_range(check, A3) || !BN_add_word(check, 2))\n            goto err;\n        j = witness(check, a, A1, A1_odd, k, ctx, mont);\n        if (j == -1)\n            goto err;\n        if (j) {\n            ret = 0;\n            goto err;\n        }\n        if (!BN_GENCB_call(cb, 1, i))\n            goto err;\n    }\n    ret = 1;\n err:\n    if (ctx != NULL) {\n        BN_CTX_end(ctx);\n        if (ctx_passed == NULL)\n            BN_CTX_free(ctx);\n    }\n    BN_MONT_CTX_free(mont);\n    return ret;\n}', 'int BN_is_word(const BIGNUM *a, const BN_ULONG w)\n{\n    return BN_abs_is_word(a, w) && (!w || !a->neg);\n}', 'int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w)\n{\n    return ((a->top == 1) && (a->d[0] == w)) || ((w == 0) && (a->top == 0));\n}', 'int BN_rshift1(BIGNUM *r, const BIGNUM *a)\n{\n    BN_ULONG *ap, *rp, t, c;\n    int i, j;\n    bn_check_top(r);\n    bn_check_top(a);\n    if (BN_is_zero(a)) {\n        BN_zero(r);\n        return 1;\n    }\n    i = a->top;\n    ap = a->d;\n    j = i - (ap[i - 1] == 1);\n    if (a != r) {\n        if (bn_wexpand(r, j) == NULL)\n            return 0;\n        r->neg = a->neg;\n    }\n    rp = r->d;\n    t = ap[--i];\n    c = (t & 1) ? BN_TBIT : 0;\n    if (t >>= 1)\n        rp[i] = t;\n    while (i > 0) {\n        t = ap[--i];\n        rp[i] = ((t >> 1) & BN_MASK2) | c;\n        c = (t & 1) ? BN_TBIT : 0;\n    }\n    r->top = j;\n    if (!r->top)\n        r->neg = 0;\n    bn_check_top(r);\n    return 1;\n}', 'int BN_is_zero(const BIGNUM *a)\n{\n    return a->top == 0;\n}', 'int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m,\n               BN_CTX *ctx)\n{\n    int ret;\n    bn_check_top(a);\n    bn_check_top(p);\n    bn_check_top(m);\n#define MONT_MUL_MOD\n#define MONT_EXP_WORD\n#define RECP_MUL_MOD\n#ifdef MONT_MUL_MOD\n    if (BN_is_odd(m)) {\n# ifdef MONT_EXP_WORD\n        if (a->top == 1 && !a->neg\n            && (BN_get_flags(p, BN_FLG_CONSTTIME) == 0)\n            && (BN_get_flags(a, BN_FLG_CONSTTIME) == 0)\n            && (BN_get_flags(m, BN_FLG_CONSTTIME) == 0)) {\n            BN_ULONG A = a->d[0];\n            ret = BN_mod_exp_mont_word(r, A, p, m, ctx, NULL);\n        } else\n# endif\n            ret = BN_mod_exp_mont(r, a, p, m, ctx, NULL);\n    } else\n#endif\n#ifdef RECP_MUL_MOD\n    {\n        ret = BN_mod_exp_recp(r, a, p, m, ctx);\n    }\n#else\n    {\n        ret = BN_mod_exp_simple(r, a, p, m, ctx);\n    }\n#endif\n    bn_check_top(r);\n    return ret;\n}', 'int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,\n                    const BIGNUM *m, BN_CTX *ctx)\n{\n    int i, j, bits, ret = 0, wstart, wend, window, wvalue;\n    int start = 1;\n    BIGNUM *aa;\n    BIGNUM *val[TABLE_SIZE];\n    BN_RECP_CTX recp;\n    if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0\n            || BN_get_flags(a, BN_FLG_CONSTTIME) != 0\n            || BN_get_flags(m, BN_FLG_CONSTTIME) != 0) {\n        BNerr(BN_F_BN_MOD_EXP_RECP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);\n        return 0;\n    }\n    bits = BN_num_bits(p);\n    if (bits == 0) {\n        if (BN_abs_is_word(m, 1)) {\n            ret = 1;\n            BN_zero(r);\n        } else {\n            ret = BN_one(r);\n        }\n        return ret;\n    }\n    BN_CTX_start(ctx);\n    aa = BN_CTX_get(ctx);\n    val[0] = BN_CTX_get(ctx);\n    if (val[0] == NULL)\n        goto err;\n    BN_RECP_CTX_init(&recp);\n    if (m->neg) {\n        if (!BN_copy(aa, m))\n            goto err;\n        aa->neg = 0;\n        if (BN_RECP_CTX_set(&recp, aa, ctx) <= 0)\n            goto err;\n    } else {\n        if (BN_RECP_CTX_set(&recp, m, ctx) <= 0)\n            goto err;\n    }\n    if (!BN_nnmod(val[0], a, m, ctx))\n        goto err;\n    if (BN_is_zero(val[0])) {\n        BN_zero(r);\n        ret = 1;\n        goto err;\n    }\n    window = BN_window_bits_for_exponent_size(bits);\n    if (window > 1) {\n        if (!BN_mod_mul_reciprocal(aa, val[0], val[0], &recp, ctx))\n            goto err;\n        j = 1 << (window - 1);\n        for (i = 1; i < j; i++) {\n            if (((val[i] = BN_CTX_get(ctx)) == NULL) ||\n                !BN_mod_mul_reciprocal(val[i], val[i - 1], aa, &recp, ctx))\n                goto err;\n        }\n    }\n    start = 1;\n    wvalue = 0;\n    wstart = bits - 1;\n    wend = 0;\n    if (!BN_one(r))\n        goto err;\n    for (;;) {\n        if (BN_is_bit_set(p, wstart) == 0) {\n            if (!start)\n                if (!BN_mod_mul_reciprocal(r, r, r, &recp, ctx))\n                    goto err;\n            if (wstart == 0)\n                break;\n            wstart--;\n            continue;\n        }\n        j = wstart;\n        wvalue = 1;\n        wend = 0;\n        for (i = 1; i < window; i++) {\n            if (wstart - i < 0)\n                break;\n            if (BN_is_bit_set(p, wstart - i)) {\n                wvalue <<= (i - wend);\n                wvalue |= 1;\n                wend = i;\n            }\n        }\n        j = wend + 1;\n        if (!start)\n            for (i = 0; i < j; i++) {\n                if (!BN_mod_mul_reciprocal(r, r, r, &recp, ctx))\n                    goto err;\n            }\n        if (!BN_mod_mul_reciprocal(r, r, val[wvalue >> 1], &recp, ctx))\n            goto err;\n        wstart -= wend + 1;\n        wvalue = 0;\n        start = 0;\n        if (wstart < 0)\n            break;\n    }\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    BN_RECP_CTX_free(&recp);\n    bn_check_top(r);\n    return ret;\n}', 'int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx)\n{\n    if (!BN_copy(&(recp->N), d))\n        return 0;\n    BN_zero(&(recp->Nr));\n    recp->num_bits = BN_num_bits(d);\n    recp->shift = 0;\n    return 1;\n}', 'BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)\n{\n    bn_check_top(b);\n    if (a == b)\n        return a;\n    if (bn_wexpand(a, b->top) == NULL)\n        return NULL;\n    if (b->top > 0)\n        memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);\n    a->top = b->top;\n    a->neg = b->neg;\n    bn_check_top(a);\n    return a;\n}', 'BIGNUM *bn_wexpand(BIGNUM *a, int words)\n{\n    return (words <= a->dmax) ? a : bn_expand2(a, words);\n}']