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BN_BN2BIN(3)			    OpenSSL			  BN_BN2BIN(3)

NAME
       BN_bn2binpad, BN_bn2bin,	BN_bin2bn, BN_bn2lebinpad, BN_lebin2bn,
       BN_bn2hex, BN_bn2dec, BN_hex2bn,	BN_dec2bn, BN_print, BN_print_fp,
       BN_bn2mpi, BN_mpi2bn - format conversions

SYNOPSIS
	#include <openssl/bn.h>

	int BN_bn2bin(const BIGNUM *a, unsigned	char *to);
	int BN_bn2binpad(const BIGNUM *a, unsigned char	*to, int tolen);
	BIGNUM *BN_bin2bn(const	unsigned char *s, int len, BIGNUM *ret);

	int BN_bn2lebinpad(const BIGNUM	*a, unsigned char *to, int tolen);
	BIGNUM *BN_lebin2bn(const unsigned char	*s, int	len, BIGNUM *ret);

	char *BN_bn2hex(const BIGNUM *a);
	char *BN_bn2dec(const BIGNUM *a);
	int BN_hex2bn(BIGNUM **a, const	char *str);
	int BN_dec2bn(BIGNUM **a, const	char *str);

	int BN_print(BIO *fp, const BIGNUM *a);
	int BN_print_fp(FILE *fp, const	BIGNUM *a);

	int BN_bn2mpi(const BIGNUM *a, unsigned	char *to);
	BIGNUM *BN_mpi2bn(unsigned char	*s, int	len, BIGNUM *ret);

DESCRIPTION
       BN_bn2bin() converts the	absolute value of a into big-endian form and
       stores it at to.	to must	point to BN_num_bytes(a) bytes of memory.

       BN_bn2binpad() also converts the	absolute value of a into big-endian
       form and	stores it at to. tolen indicates the length of the output
       buffer to. The result is	padded with zeroes if necessary. If tolen is
       less than BN_num_bytes(a) an error is returned.

       BN_bin2bn() converts the	positive integer in big-endian form of length
       len at s	into a BIGNUM and places it in ret. If ret is NULL, a new
       BIGNUM is created.

       BN_bn2lebinpad()	and BN_lebin2bn() are identical	to BN_bn2binpad() and
       BN_bin2bn() except the buffer is	in little-endian format.

       BN_bn2hex() and BN_bn2dec() return printable strings containing the
       hexadecimal and decimal encoding	of a respectively. For negative
       numbers,	the string is prefaced with a leading '-'. The string must be
       freed later using OPENSSL_free().

       BN_hex2bn() takes as many characters as possible	from the string	str,
       including the leading character '-' which means negative, to form a
       valid hexadecimal number	representation and converts them to a BIGNUM
       and stores it in	**a. If	*a is NULL, a new BIGNUM is created. If	a is
       NULL, it	only computes the length of valid representation.  A "negative
       zero" is	converted to zero.  BN_dec2bn()	is the same using the decimal
       system.

       BN_print() and BN_print_fp() write the hexadecimal encoding of a, with
       a leading '-' for negative numbers, to the BIO or FILE fp.

       BN_bn2mpi() and BN_mpi2bn() convert BIGNUMs from	and to a format	that
       consists	of the number's	length in bytes	represented as a 4-byte	big-
       endian number, and the number itself in big-endian format, where	the
       most significant	bit signals a negative number (the representation of
       numbers with the	MSB set	is prefixed with null byte).

       BN_bn2mpi() stores the representation of	a at to, where to must be
       large enough to hold the	result.	The size can be	determined by calling
       BN_bn2mpi(a, NULL).

       BN_mpi2bn() converts the	len bytes long representation at s to a	BIGNUM
       and stores it at	ret, or	in a newly allocated BIGNUM if ret is NULL.

RETURN VALUES
       BN_bn2bin() returns the length of the big-endian	number placed at to.
       BN_bin2bn() returns the BIGNUM, NULL on error.

       BN_bn2binpad() returns the number of bytes written or -1	if the
       supplied	buffer is too small.

       BN_bn2hex() and BN_bn2dec() return a null-terminated string, or NULL on
       error. BN_hex2bn() and BN_dec2bn() return the number of characters used
       in parsing, or 0	on error, in which case	no new BIGNUM will be created.

       BN_print_fp() and BN_print() return 1 on	success, 0 on write errors.

       BN_bn2mpi() returns the length of the representation. BN_mpi2bn()
       returns the BIGNUM, and NULL on error.

       The error codes can be obtained by ERR_get_error(3).

SEE ALSO
       ERR_get_error(3), BN_zero(3), ASN1_INTEGER_to_BN(3), BN_num_bytes(3)

COPYRIGHT
       Copyright 2000-2018 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>.

1.1.1d				  2019-09-10			  BN_BN2BIN(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | SEE ALSO | COPYRIGHT

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