NAME    [Toc]    [Back]

       BN_bn2bin, BN_bin2bn, BN_bn2hex, BN_bn2dec, BN_hex2bn,
       BN_dec2bn, BN_print, BN_print_fp, BN_bn2mpi, BN_mpi2bn -
       format conversions

SYNOPSIS    [Toc]    [Back]

        #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    [Toc]    [Back]

       BN_bn2bin() converts the absolute value of a into bigendian
 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    [Toc]    [Back]

       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    [Toc]    [Back]

       bn(3), ERR_get_error(3), BN_zero(3),
       ASN1_INTEGER_to_BN(3), BN_num_bytes(3)

HISTORY    [Toc]    [Back]

       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.


OpenBSD 3.6                 2002-05-14                          2