=pod =head1 NAME BN_bn2bin, BN_bin2bn, BN_bn2hex, BN_bn2dec, BN_hex2bn, BN_dec2bn, BN_print, BN_print_fp, BN_bn2mpi, BN_mpi2bn - format conversions =head1 SYNOPSIS #include 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); =head1 DESCRIPTION BN_bn2bin() converts the absolute value of B into big-endian form and stores it at B. B must point to BN_num_bytes(B) bytes of memory. BN_bin2bn() converts the positive integer in big-endian form of length B at B into a B and places it in B. If B is NULL, a new B is created. BN_bn2hex() and BN_bn2dec() return printable strings containing the hexadecimal and decimal encoding of B 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 B containing a hexadecimal number to a B and stores it in **B. If *B is NULL, a new B is created. If B 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 B, with a leading '-' for negative numbers, to the B or B B. BN_bn2mpi() and BN_mpi2bn() convert Bs 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 B at B, where B must be large enough to hold the result. The size can be determined by calling BN_bn2mpi(B, NULL). BN_mpi2bn() converts the B bytes long representation at B to a B and stores it at B, or in a newly allocated B if B is NULL. =head1 RETURN VALUES BN_bn2bin() returns the length of the big-endian number placed at B. BN_bin2bn() returns the B, 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 B, and NULL on error. The error codes can be obtained by L. =head1 SEE ALSO L, L, L, L, L =head1 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. =cut