BN_BN2BIN(3) BSD Library Functions Manual 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);
DESCRIPTIONBN_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 hexa‐
decimal and decimal encoding of a respectively. For negative numbers,
the string is prefaced with a leading minus sign. The string must be
freed later using free(3).
BN_hex2bn() converts the string str containing a hexadecimal number 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 number's length in hexadecimal digits.
If the string starts with a minus sign, 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 minus sign 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 a NUL 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 VALUESBN_bn2bin() returns the length of the big-endian number placed at to.
BN_bin2bn() returns the BIGNUM, or NULL on error.
BN_bn2hex() and BN_bn2dec() return a NUL-terminated string, or NULL on
error. BN_hex2bn() and BN_dec2bn() return the number's length in hexa‐
decimal 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, or NULL on error.
The error codes can be obtained by ERR_get_error(3).
SEE ALSOASN1_INTEGER_to_BN(3), bn(3), BN_num_bytes(3), BN_zero(3),
ERR_get_error(3)HISTORYBN_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.
BSD April 20, 2024 BSD
