コード例 #1
0
ファイル: exptest.c プロジェクト: Castaglia/openssl
/*
 * test_exp_mod_zero tests that x**0 mod 1 == 0. It returns zero on success.
 */
static int test_exp_mod_zero()
{
    BIGNUM *a = NULL, *p = NULL, *m = NULL;
    BIGNUM *r = NULL;
    BN_ULONG one_word = 1;
    BN_CTX *ctx = BN_CTX_new();
    int ret = 1, failed = 0;

    m = BN_new();
    if (!m)
        goto err;
    BN_one(m);

    a = BN_new();
    if (!a)
        goto err;
    BN_one(a);

    p = BN_new();
    if (!p)
        goto err;
    BN_zero(p);

    r = BN_new();
    if (!r)
        goto err;

    if (!BN_rand(a, 1024, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY))
        goto err;

    if (!BN_mod_exp(r, a, p, m, ctx))
        goto err;

    if (!a_is_zero_mod_one("BN_mod_exp", r, a))
        failed = 1;

    if (!BN_mod_exp_recp(r, a, p, m, ctx))
        goto err;

    if (!a_is_zero_mod_one("BN_mod_exp_recp", r, a))
        failed = 1;

    if (!BN_mod_exp_simple(r, a, p, m, ctx))
        goto err;

    if (!a_is_zero_mod_one("BN_mod_exp_simple", r, a))
        failed = 1;

    if (!BN_mod_exp_mont(r, a, p, m, ctx, NULL))
        goto err;

    if (!a_is_zero_mod_one("BN_mod_exp_mont", r, a))
        failed = 1;

    if (!BN_mod_exp_mont_consttime(r, a, p, m, ctx, NULL)) {
        goto err;
    }

    if (!a_is_zero_mod_one("BN_mod_exp_mont_consttime", r, a))
        failed = 1;

    /*
     * A different codepath exists for single word multiplication
     * in non-constant-time only.
     */
    if (!BN_mod_exp_mont_word(r, one_word, p, m, ctx, NULL))
        goto err;

    if (!BN_is_zero(r)) {
        fprintf(stderr, "BN_mod_exp_mont_word failed:\n");
        fprintf(stderr, "1 ** 0 mod 1 = r (should be 0)\n");
        fprintf(stderr, "r = ");
        BN_print_fp(stderr, r);
        fprintf(stderr, "\n");
        return 0;
    }

    ret = failed;

 err:
    BN_free(r);
    BN_free(a);
    BN_free(p);
    BN_free(m);
    BN_CTX_free(ctx);

    return ret;
}
コード例 #2
0
ファイル: exptest.c プロジェクト: 1564143452/kbengine
int main(int argc, char *argv[])
{
    BN_CTX *ctx;
    BIO *out = NULL;
    int i, ret;
    unsigned char c;
    BIGNUM *r_mont, *r_mont_const, *r_recp, *r_simple, *a, *b, *m;

    RAND_seed(rnd_seed, sizeof rnd_seed); /* or BN_rand may fail, and we
                                           * don't even check its return
                                           * value (which we should) */

    ERR_load_BN_strings();

    ctx = BN_CTX_new();
    if (ctx == NULL)
        EXIT(1);
    r_mont = BN_new();
    r_mont_const = BN_new();
    r_recp = BN_new();
    r_simple = BN_new();
    a = BN_new();
    b = BN_new();
    m = BN_new();
    if ((r_mont == NULL) || (r_recp == NULL) || (a == NULL) || (b == NULL))
        goto err;

    out = BIO_new(BIO_s_file());

    if (out == NULL)
        EXIT(1);
    BIO_set_fp(out, stdout, BIO_NOCLOSE);

    for (i = 0; i < 200; i++) {
        RAND_bytes(&c, 1);
        c = (c % BN_BITS) - BN_BITS2;
        BN_rand(a, NUM_BITS + c, 0, 0);

        RAND_bytes(&c, 1);
        c = (c % BN_BITS) - BN_BITS2;
        BN_rand(b, NUM_BITS + c, 0, 0);

        RAND_bytes(&c, 1);
        c = (c % BN_BITS) - BN_BITS2;
        BN_rand(m, NUM_BITS + c, 0, 1);

        BN_mod(a, a, m, ctx);
        BN_mod(b, b, m, ctx);

        ret = BN_mod_exp_mont(r_mont, a, b, m, ctx, NULL);
        if (ret <= 0) {
            printf("BN_mod_exp_mont() problems\n");
            ERR_print_errors(out);
            EXIT(1);
        }

        ret = BN_mod_exp_recp(r_recp, a, b, m, ctx);
        if (ret <= 0) {
            printf("BN_mod_exp_recp() problems\n");
            ERR_print_errors(out);
            EXIT(1);
        }

        ret = BN_mod_exp_simple(r_simple, a, b, m, ctx);
        if (ret <= 0) {
            printf("BN_mod_exp_simple() problems\n");
            ERR_print_errors(out);
            EXIT(1);
        }

        ret = BN_mod_exp_mont_consttime(r_mont_const, a, b, m, ctx, NULL);
        if (ret <= 0) {
            printf("BN_mod_exp_mont_consttime() problems\n");
            ERR_print_errors(out);
            EXIT(1);
        }

        if (BN_cmp(r_simple, r_mont) == 0
            && BN_cmp(r_simple, r_recp) == 0
            && BN_cmp(r_simple, r_mont_const) == 0) {
            printf(".");
            fflush(stdout);
        } else {
            if (BN_cmp(r_simple, r_mont) != 0)
                printf("\nsimple and mont results differ\n");
            if (BN_cmp(r_simple, r_mont_const) != 0)
                printf("\nsimple and mont const time results differ\n");
            if (BN_cmp(r_simple, r_recp) != 0)
                printf("\nsimple and recp results differ\n");

            printf("a (%3d) = ", BN_num_bits(a));
            BN_print(out, a);
            printf("\nb (%3d) = ", BN_num_bits(b));
            BN_print(out, b);
            printf("\nm (%3d) = ", BN_num_bits(m));
            BN_print(out, m);
            printf("\nsimple   =");
            BN_print(out, r_simple);
            printf("\nrecp     =");
            BN_print(out, r_recp);
            printf("\nmont     =");
            BN_print(out, r_mont);
            printf("\nmont_ct  =");
            BN_print(out, r_mont_const);
            printf("\n");
            EXIT(1);
        }
    }
    BN_free(r_mont);
    BN_free(r_mont_const);
    BN_free(r_recp);
    BN_free(r_simple);
    BN_free(a);
    BN_free(b);
    BN_free(m);
    BN_CTX_free(ctx);
    ERR_remove_thread_state(NULL);
    CRYPTO_mem_leaks(out);
    BIO_free(out);
    printf("\n");

    if (test_exp_mod_zero() != 0)
        goto err;

    printf("done\n");

    EXIT(0);
 err:
    ERR_load_crypto_strings();
    ERR_print_errors(out);
#ifdef OPENSSL_SYS_NETWARE
    printf("ERROR\n");
#endif
    EXIT(1);
    return (1);
}
コード例 #3
0
ファイル: bntest.c プロジェクト: froggatt/edimax-br-6528n
int test_kron(BIO *bp, BN_CTX *ctx)
	{
	BIGNUM *a,*b,*r,*t;
	int i;
	int legendre, kronecker;
	int ret = 0;

	a = BN_new();
	b = BN_new();
	r = BN_new();
	t = BN_new();
	if (a == NULL || b == NULL || r == NULL || t == NULL) goto err;
	
	/* We test BN_kronecker(a, b, ctx) just for  b  odd (Jacobi symbol).
	 * In this case we know that if  b  is prime, then BN_kronecker(a, b, ctx)
	 * is congruent to $a^{(b-1)/2}$, modulo $b$ (Legendre symbol).
	 * So we generate a random prime  b  and compare these values
	 * for a number of random  a's.  (That is, we run the Solovay-Strassen
	 * primality test to confirm that  b  is prime, except that we
	 * don't want to test whether  b  is prime but whether BN_kronecker
	 * works.) */

	if (!BN_generate_prime(b, 512, 0, NULL, NULL, genprime_cb, NULL)) goto err;
	b->neg = rand_neg();
	putc('\n', stderr);

	for (i = 0; i < num0; i++)
		{
		if (!BN_bntest_rand(a, 512, 0, 0)) goto err;
		a->neg = rand_neg();

		/* t := (|b|-1)/2  (note that b is odd) */
		if (!BN_copy(t, b)) goto err;
		t->neg = 0;
		if (!BN_sub_word(t, 1)) goto err;
		if (!BN_rshift1(t, t)) goto err;
		/* r := a^t mod b */
		b->neg=0;
		
		if (!BN_mod_exp_recp(r, a, t, b, ctx)) goto err;
		b->neg=1;

		if (BN_is_word(r, 1))
			legendre = 1;
		else if (BN_is_zero(r))
			legendre = 0;
		else
			{
			if (!BN_add_word(r, 1)) goto err;
			if (0 != BN_ucmp(r, b))
				{
				fprintf(stderr, "Legendre symbol computation failed\n");
				goto err;
				}
			legendre = -1;
			}
		
		kronecker = BN_kronecker(a, b, ctx);
		if (kronecker < -1) goto err;
		/* we actually need BN_kronecker(a, |b|) */
		if (a->neg && b->neg)
			kronecker = -kronecker;
		
		if (legendre != kronecker)
			{
			fprintf(stderr, "legendre != kronecker; a = ");
			BN_print_fp(stderr, a);
			fprintf(stderr, ", b = ");
			BN_print_fp(stderr, b);
			fprintf(stderr, "\n");
			goto err;
			}

		putc('.', stderr);
		fflush(stderr);
		}

	putc('\n', stderr);
	fflush(stderr);
	ret = 1;
 err:
	if (a != NULL) BN_free(a);
	if (b != NULL) BN_free(b);
	if (r != NULL) BN_free(r);
	if (t != NULL) BN_free(t);
	return ret;
	}
コード例 #4
0
ファイル: exptest.c プロジェクト: Ana06/openssl
/*
 * test_mod_exp_zero tests that x**0 mod 1 == 0. It returns zero on success.
 */
static int test_mod_exp_zero(void)
{
    BIGNUM *a = NULL, *p = NULL, *m = NULL;
    BIGNUM *r = NULL;
    BN_ULONG one_word = 1;
    BN_CTX *ctx = BN_CTX_new();
    int ret = 1, failed = 0;

    if (!TEST_ptr(m = BN_new())
        || !TEST_ptr(a = BN_new())
        || !TEST_ptr(p = BN_new())
        || !TEST_ptr(r = BN_new()))
        goto err;

    BN_one(m);
    BN_one(a);
    BN_zero(p);

    if (!TEST_true(BN_rand(a, 1024, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY)))
        goto err;

    if (!TEST_true(BN_mod_exp(r, a, p, m, ctx)))
        goto err;

    if (!TEST_true(a_is_zero_mod_one("BN_mod_exp", r, a)))
        failed = 1;

    if (!TEST_true(BN_mod_exp_recp(r, a, p, m, ctx)))
        goto err;

    if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_recp", r, a)))
        failed = 1;

    if (!TEST_true(BN_mod_exp_simple(r, a, p, m, ctx)))
        goto err;

    if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_simple", r, a)))
        failed = 1;

    if (!TEST_true(BN_mod_exp_mont(r, a, p, m, ctx, NULL)))
        goto err;

    if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_mont", r, a)))
        failed = 1;

    if (!TEST_true(BN_mod_exp_mont_consttime(r, a, p, m, ctx, NULL)))
        goto err;

    if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_mont_consttime", r, a)))
        failed = 1;

    /*
     * A different codepath exists for single word multiplication
     * in non-constant-time only.
     */
    if (!TEST_true(BN_mod_exp_mont_word(r, one_word, p, m, ctx, NULL)))
        goto err;

    if (!TEST_BN_eq_zero(r)) {
        TEST_error("BN_mod_exp_mont_word failed: "
                   "1 ** 0 mod 1 = r (should be 0)");
        BN_print_var(r);
        goto err;
    }

    ret = !failed;
 err:
    BN_free(r);
    BN_free(a);
    BN_free(p);
    BN_free(m);
    BN_CTX_free(ctx);

    return ret;
}
コード例 #5
0
ファイル: exptest.c プロジェクト: Ana06/openssl
static int test_mod_exp(int round)
{
    BN_CTX *ctx;
    unsigned char c;
    int ret = 0;
    BIGNUM *r_mont = NULL;
    BIGNUM *r_mont_const = NULL;
    BIGNUM *r_recp = NULL;
    BIGNUM *r_simple = NULL;
    BIGNUM *a = NULL;
    BIGNUM *b = NULL;
    BIGNUM *m = NULL;

    if (!TEST_ptr(ctx = BN_CTX_new()))
        goto err;

    if (!TEST_ptr(r_mont = BN_new())
        || !TEST_ptr(r_mont_const = BN_new())
        || !TEST_ptr(r_recp = BN_new())
        || !TEST_ptr(r_simple = BN_new())
        || !TEST_ptr(a = BN_new())
        || !TEST_ptr(b = BN_new())
        || !TEST_ptr(m = BN_new()))
        goto err;

    RAND_bytes(&c, 1);
    c = (c % BN_BITS) - BN_BITS2;
    BN_rand(a, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);

    RAND_bytes(&c, 1);
    c = (c % BN_BITS) - BN_BITS2;
    BN_rand(b, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);

    RAND_bytes(&c, 1);
    c = (c % BN_BITS) - BN_BITS2;
    BN_rand(m, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD);

    if (!TEST_true(BN_mod(a, a, m, ctx))
        || !TEST_true(BN_mod(b, b, m, ctx))
        || !TEST_true(BN_mod_exp_mont(r_mont, a, b, m, ctx, NULL))
        || !TEST_true(BN_mod_exp_recp(r_recp, a, b, m, ctx))
        || !TEST_true(BN_mod_exp_simple(r_simple, a, b, m, ctx))
        || !TEST_true(BN_mod_exp_mont_consttime(r_mont_const, a, b, m, ctx, NULL)))
        goto err;

    if (!TEST_BN_eq(r_simple, r_mont)
        || !TEST_BN_eq(r_simple, r_recp)
        || !TEST_BN_eq(r_simple, r_mont_const)) {
        if (BN_cmp(r_simple, r_mont) != 0)
            TEST_info("simple and mont results differ");
        if (BN_cmp(r_simple, r_mont_const) != 0)
            TEST_info("simple and mont const time results differ");
        if (BN_cmp(r_simple, r_recp) != 0)
            TEST_info("simple and recp results differ");

        BN_print_var(a);
        BN_print_var(b);
        BN_print_var(m);
        BN_print_var(r_simple);
        BN_print_var(r_recp);
        BN_print_var(r_mont);
        BN_print_var(r_mont_const);
        goto err;
    }

    ret = 1;
 err:
    BN_free(r_mont);
    BN_free(r_mont_const);
    BN_free(r_recp);
    BN_free(r_simple);
    BN_free(a);
    BN_free(b);
    BN_free(m);
    BN_CTX_free(ctx);

    return ret;
}
コード例 #6
0
ファイル: exptest.c プロジェクト: kuailexs/symbiandump-os2
int exp_main(int argc, char *argv[])
#endif
{
    BN_CTX *ctx;
    BIO *out=NULL;
    int i,ret;
    unsigned char c;
    BIGNUM *r_mont,*r_mont_const,*r_recp,*r_simple,*a,*b,*m;
    //	FILE* temp;


    RAND_seed(rnd_seed, sizeof rnd_seed); /* or BN_rand may fail, and we don't
	                                       * even check its return value
	                                       * (which we should) */
    if(errno==ENOMEM)
    {
        return 1;
    }

    ERR_load_BN_strings();
    if(errno==ENOMEM)
    {
        return 1;
    }

    ctx=BN_CTX_new();
    if (ctx == NULL)
    {
        if(errno==ENOMEM)
        {
            return 1;
        }
        return 1;
    }
    r_mont=BN_new();
    if(r_mont==NULL&&errno==ENOMEM)
    {
        return 1;
    }
    r_mont_const=BN_new();
    if(r_mont_const==NULL&&errno==ENOMEM)
    {
        return 1;
    }

    r_recp=BN_new();
    if(r_recp==NULL&&errno==ENOMEM)
    {
        return 1;
    }

    r_simple=BN_new();
    if(r_simple==NULL&&errno==ENOMEM)
    {
        return 1;
    }

    a=BN_new();
    if(a==NULL&&errno==ENOMEM)
    {
        return 1;
    }

    b=BN_new();
    if(b==NULL&&errno==ENOMEM)
    {
        return 1;
    }

    m=BN_new();
    if(m==NULL&&errno==ENOMEM)
    {
        return 1;
    }

    if (	(r_mont == NULL) || (r_recp == NULL) ||
            (a == NULL) || (b == NULL))
        goto err;

    out=BIO_new(BIO_s_file());
    if(out==NULL&&errno==ENOMEM)
    {
        return 1;
    }
    if (out == NULL)
        return 1;
    BIO_set_fp(out,stdout,BIO_NOCLOSE);
    if(errno==ENOMEM)
    {
        return 1;
    }

// temp = fopen("sanjeev.txt", "w");

    for (i=0; i<200; i++)
    {
        //	fputc(i,temp);
        RAND_bytes(&c,1);
        if(errno==ENOMEM)
        {
            return 1;
        }

        c=(c%BN_BITS)-BN_BITS2;
        BN_rand(a,NUM_BITS+c,0,0);
        if(errno==ENOMEM)
        {
            return 1;
        }
        RAND_bytes(&c,1);
        if(errno==ENOMEM)
        {
            return 1;
        }
        c=(c%BN_BITS)-BN_BITS2;
        BN_rand(b,NUM_BITS+c,0,0);
        if(errno==ENOMEM)
        {
            return 1;
        }
        RAND_bytes(&c,1);
        if(errno==ENOMEM)
        {
            return 1;
        }

        c=(c%BN_BITS)-BN_BITS2;
        BN_rand(m,NUM_BITS+c,0,1);
        if(errno==ENOMEM)
        {
            return 1;
        }

        BN_mod(a,a,m,ctx);
        if(errno==ENOMEM)
        {
            return 1;
        }

        BN_mod(b,b,m,ctx);
        if(errno==ENOMEM)
        {
            return 1;
        }

        ret=BN_mod_exp_mont(r_mont,a,b,m,ctx,NULL);
        if (ret <= 0)
        {
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"BN_mod_exp_mont() problems\n");
            ERR_print_errors(out);
            if(errno==ENOMEM)
            {
                return 1;
            }
            return 1;
        }

        ret=BN_mod_exp_recp(r_recp,a,b,m,ctx);
        if (ret <= 0)
        {
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"BN_mod_exp_recp() problems\n");
            ERR_print_errors(out);
            if(errno==ENOMEM)
            {
                return 1;
            }
            return 1;
        }

        ret=BN_mod_exp_simple(r_simple,a,b,m,ctx);
        if (ret <= 0)
        {
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"BN_mod_exp_simple() problems\n");
            ERR_print_errors(out);
            if(errno==ENOMEM)
            {
                return 1;
            }
            return 1;
        }

        ret=BN_mod_exp_mont_consttime(r_mont_const,a,b,m,ctx,NULL);
        if (ret <= 0)
        {
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"BN_mod_exp_mont_consttime() problems\n");
            ERR_print_errors(out);
            if(errno==ENOMEM)
            {
                return 1;
            }
            return 1;
        }

        if (BN_cmp(r_simple, r_mont) == 0
                && BN_cmp(r_simple,r_recp) == 0
                && BN_cmp(r_simple,r_mont_const) == 0)
        {
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,".");
            fflush(stdout);
        }
        else
        {
            if (BN_cmp(r_simple,r_mont) != 0)
            {
                if(errno==ENOMEM)
                {
                    return 1;
                }
                fprintf(stdout,"\nsimple and mont results differ\n");
            }
            if (BN_cmp(r_simple,r_mont) != 0)
            {
                if(errno==ENOMEM)
                {
                    return 1;
                }
                fprintf(stdout,"\nsimple and mont const time results differ\n");
            }
            if (BN_cmp(r_simple,r_recp) != 0)
            {
                if(errno==ENOMEM)
                {
                    return 1;
                }
                fprintf(stdout,"\nsimple and recp results differ\n");
            }
            fprintf(stdout,"a (%3d) = ",BN_num_bits(a));
            BN_print(out,a);
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"\nb (%3d) = ",BN_num_bits(b));
            BN_print(out,b);
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"\nm (%3d) = ",BN_num_bits(m));
            BN_print(out,m);
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"\nsimple   =");
            BN_print(out,r_simple);
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"\nrecp     =");
            BN_print(out,r_recp);
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"\nmont     =");
            BN_print(out,r_mont);
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"\nmont_ct  =");
            BN_print(out,r_mont_const);
            if(errno==ENOMEM)
            {
                return 1;
            }
            fprintf(stdout,"\n");
            return 1;
        }
    }
    BN_free(r_mont);
    BN_free(r_mont_const);
    BN_free(r_recp);
    BN_free(r_simple);
    BN_free(a);
    BN_free(b);
    BN_free(m);
    BN_CTX_free(ctx);
    ERR_remove_state(0);
    if(errno==ENOMEM)
    {
        return 1;
    }
    CRYPTO_mem_leaks(out);
    if(errno==ENOMEM)
    {
        return 1;
    }
    BIO_free(out);
    if(errno==ENOMEM)
    {
        return 1;
    }

    CRYPTO_cleanup_all_ex_data();
    if(errno==ENOMEM)
    {
        return 1;
    }

    fprintf(stdout," done\n");
    fprintf(stdout," Test case passed\n");
    return 0;
err:
    ERR_load_crypto_strings();
    if(errno==ENOMEM)
    {
        return 1;
    }

    ERR_print_errors(out);
    if(errno==ENOMEM)
    {
        return 1;
    }


#ifdef OPENSSL_SYS_NETWARE
    fprintf(stdout,"ERROR\n");
#endif
    return(1);
}
コード例 #7
0
ファイル: exptest.c プロジェクト: IIJ-NetBSD/netbsd-src
/*
 * test_exp_mod_zero tests that x**0 mod 1 == 0. It returns zero on success.
 */
static int test_exp_mod_zero(void)
{
    BIGNUM a, p, m;
    BIGNUM r;
    BN_ULONG one_word = 1;
    BN_CTX *ctx = BN_CTX_new();
    int ret = 1, failed = 0;

    BN_init(&m);
    BN_one(&m);

    BN_init(&a);
    BN_one(&a);

    BN_init(&p);
    BN_zero(&p);

    BN_init(&r);

    if (!BN_rand(&a, 1024, 0, 0))
        goto err;

    if (!BN_mod_exp(&r, &a, &p, &m, ctx))
        goto err;

    if (!a_is_zero_mod_one("BN_mod_exp", &r, &a))
        failed = 1;

    if (!BN_mod_exp_recp(&r, &a, &p, &m, ctx))
        goto err;

    if (!a_is_zero_mod_one("BN_mod_exp_recp", &r, &a))
        failed = 1;

    if (!BN_mod_exp_simple(&r, &a, &p, &m, ctx))
        goto err;

    if (!a_is_zero_mod_one("BN_mod_exp_simple", &r, &a))
        failed = 1;

    if (!BN_mod_exp_mont(&r, &a, &p, &m, ctx, NULL))
        goto err;

    if (!a_is_zero_mod_one("BN_mod_exp_mont", &r, &a))
        failed = 1;

    if (!BN_mod_exp_mont_consttime(&r, &a, &p, &m, ctx, NULL)) {
        goto err;
    }

    if (!a_is_zero_mod_one("BN_mod_exp_mont_consttime", &r, &a))
        failed = 1;

    /*
     * A different codepath exists for single word multiplication
     * in non-constant-time only.
     */
    if (!BN_mod_exp_mont_word(&r, one_word, &p, &m, ctx, NULL))
        goto err;

    if (!BN_is_zero(&r)) {
        fprintf(stderr, "BN_mod_exp_mont_word failed:\n");
        fprintf(stderr, "1 ** 0 mod 1 = r (should be 0)\n");
        fprintf(stderr, "r = ");
        BN_print_fp(stderr, &r);
        fprintf(stderr, "\n");
        return 0;
    }

    ret = failed;

 err:
    BN_free(&r);
    BN_free(&a);
    BN_free(&p);
    BN_free(&m);
    BN_CTX_free(ctx);

    return ret;
}