BN_bn2bin
Section: OpenSSL (3)
Updated: 2017-05-25
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NAME
BN_bn2bin, BN_bin2bn, 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);
BIGNUM *BN_bin2bn(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_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_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() converts the string str containing a hexadecimal number
to a BIGNUM and stores it in **bn. If *bn is NULL, a new
BIGNUM is created. If bn is NULL, it only computes the number's
length in hexadecimal digits. If the string starts with '-', the
number is negative.
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_bn2hex() and BN_bn2dec() return a null-terminated string, or NULL
on error. BN_hex2bn() and BN_dec2bn() return the number's length in
hexadecimal or decimal digits, and 0 on error.
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
bn(3),
ERR_get_error(3),
BN_zero(3),
ASN1_INTEGER_to_BN(3),
BN_num_bytes(3)
HISTORY
BN_bn2bin(),
BN_bin2bn(),
BN_print_fp() and
BN_print() are available
in all versions of SSLeay and OpenSSL.
BN_bn2hex(), BN_bn2dec(), BN_hex2bn(), BN_dec2bn(), BN_bn2mpi() and
BN_mpi2bn() were added in SSLeay 0.9.0.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUES
-
- SEE ALSO
-
- HISTORY
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