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.
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.