BN_bn2bin(3) OpenSSL BN_bn2bin(3)
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.
0.9.7l 2002-09-25 BN_bn2bin(3)
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