BN_bn2bin(3)

     BN_bn2bin(3)           0.9.6h (2002-09-25)           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

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     BN_bn2bin(3)           0.9.6h (2002-09-25)           BN_bn2bin(3)

          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.

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