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BN_ADD(3)			    OpenSSL			     BN_ADD(3)

NAME
       BN_add, BN_sub, BN_mul, BN_sqr, BN_div, BN_mod, BN_nnmod, BN_mod_add,
       BN_mod_sub, BN_mod_mul, BN_mod_sqr, BN_exp, BN_mod_exp, BN_gcd -
       arithmetic operations on	BIGNUMs

SYNOPSIS
	#include <openssl/bn.h>

	int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);

	int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);

	int BN_mul(BIGNUM *r, BIGNUM *a, BIGNUM	*b, BN_CTX *ctx);

	int BN_sqr(BIGNUM *r, BIGNUM *a, BN_CTX	*ctx);

	int BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *a, const BIGNUM *d,
		   BN_CTX *ctx);

	int BN_mod(BIGNUM *rem,	const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx);

	int BN_nnmod(BIGNUM *r,	const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx);

	int BN_mod_add(BIGNUM *r, BIGNUM *a, BIGNUM *b,	const BIGNUM *m,
		       BN_CTX *ctx);

	int BN_mod_sub(BIGNUM *r, BIGNUM *a, BIGNUM *b,	const BIGNUM *m,
		       BN_CTX *ctx);

	int BN_mod_mul(BIGNUM *r, BIGNUM *a, BIGNUM *b,	const BIGNUM *m,
		       BN_CTX *ctx);

	int BN_mod_sqr(BIGNUM *r, BIGNUM *a, const BIGNUM *m, BN_CTX *ctx);

	int BN_exp(BIGNUM *r, BIGNUM *a, BIGNUM	*p, BN_CTX *ctx);

	int BN_mod_exp(BIGNUM *r, BIGNUM *a, const BIGNUM *p,
		       const BIGNUM *m,	BN_CTX *ctx);

	int BN_gcd(BIGNUM *r, BIGNUM *a, BIGNUM	*b, BN_CTX *ctx);

DESCRIPTION
       BN_add()	adds a and b and places	the result in r	("r=a+b").  r may be
       the same	BIGNUM as a or b.

       BN_sub()	subtracts b from a and places the result in r ("r=a-b").  r
       may be the same BIGNUM as a or b.

       BN_mul()	multiplies a and b and places the result in r ("r=a*b").  r
       may be the same BIGNUM as a or b.  For multiplication by	powers of 2,
       use BN_lshift(3).

       BN_sqr()	takes the square of a and places the result in r ("r=a^2"). r
       and a may be the	same BIGNUM.  This function is faster than
       BN_mul(r,a,a).

       BN_div()	divides	a by d and places the result in	dv and the remainder
       in rem ("dv=a/d,	rem=a%d"). Either of dv	and rem	may be NULL, in	which
       case the	respective value is not	returned.  The result is rounded
       towards zero; thus if a is negative, the	remainder will be zero or
       negative.  For division by powers of 2, use BN_rshift(3).

       BN_mod()	corresponds to BN_div()	with dv	set to NULL.

       BN_nnmod() reduces a modulo m and places	the nonnegative	remainder in
       r.

       BN_mod_add() adds a to b	modulo m and places the	nonnegative result in
       r.

       BN_mod_sub() subtracts b	from a modulo m	and places the nonnegative
       result in r.

       BN_mod_mul() multiplies a by b and finds	the nonnegative	remainder
       respective to modulus m ("r=(a*b) mod m"). r may	be the same BIGNUM as
       a or b. For more	efficient algorithms for repeated computations using
       the same	modulus, see BN_mod_mul_montgomery(3) and
       BN_mod_mul_reciprocal(3).

       BN_mod_sqr() takes the square of	a modulo m and places the result in r.

       BN_exp()	raises a to the	p-th power and places the result in r
       ("r=a^p"). This function	is faster than repeated	applications of
       BN_mul().

       BN_mod_exp() computes a to the p-th power modulo	m ("r=a^p % m"). This
       function	uses less time and space than BN_exp().	Do not call this
       function	when m is even and any of the parameters have the
       BN_FLG_CONSTTIME	flag set.

       BN_gcd()	computes the greatest common divisor of	a and b	and places the
       result in r. r may be the same BIGNUM as	a or b.

       For all functions, ctx is a previously allocated	BN_CTX used for
       temporary variables; see	BN_CTX_new(3).

       Unless noted otherwise, the result BIGNUM must be different from	the
       arguments.

RETURN VALUES
       For all functions, 1 is returned	for success, 0 on error. The return
       value should always be checked (e.g., "if (!BN_add(r,a,b)) goto err;").
       The error codes can be obtained by ERR_get_error(3).

SEE ALSO
       ERR_get_error(3), BN_CTX_new(3),	BN_add_word(3),	BN_set_bit(3)

COPYRIGHT
       Copyright 2000-2020 The OpenSSL Project Authors.	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>.

1.1.1k				  2021-03-25			     BN_ADD(3)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | SEE ALSO | COPYRIGHT

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