5 BN_bn2bin, BN_bin2bn, BN_bn2lebinpad, BN_lebin2bn, BN_bn2hex, BN_bn2dec,
6 BN_hex2bn, BN_dec2bn, BN_print, BN_print_fp, BN_bn2mpi,
7 BN_mpi2bn - format conversions
11 #include <openssl/bn.h>
13 int BN_bn2bin(const BIGNUM *a, unsigned char *to);
14 int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen);
15 BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret);
17 int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen);
18 BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret);
20 char *BN_bn2hex(const BIGNUM *a);
21 char *BN_bn2dec(const BIGNUM *a);
22 int BN_hex2bn(BIGNUM **a, const char *str);
23 int BN_dec2bn(BIGNUM **a, const char *str);
25 int BN_print(BIO *fp, const BIGNUM *a);
26 int BN_print_fp(FILE *fp, const BIGNUM *a);
28 int BN_bn2mpi(const BIGNUM *a, unsigned char *to);
29 BIGNUM *BN_mpi2bn(unsigned char *s, int len, BIGNUM *ret);
33 BN_bn2bin() converts the absolute value of B<a> into big-endian form
34 and stores it at B<to>. B<to> must point to BN_num_bytes(B<a>) bytes of
37 BN_bn2binpad() also converts the absolute value of B<a> into big-endian form
38 and stores it at B<to>. B<tolen> indicates the length of the output buffer
39 B<to>. The result is padded with zeroes if necessary. If B<tolen> is less than
40 BN_num_bytes(B<a>) an error is returned.
42 BN_bin2bn() converts the positive integer in big-endian form of length
43 B<len> at B<s> into a B<BIGNUM> and places it in B<ret>. If B<ret> is
44 NULL, a new B<BIGNUM> is created.
46 BN_bn2lebinpad() and BN_bin2lbn() are identical to BN_bn2binpad() and
47 BN_bin2bn() except the buffer is in little-endian format.
49 BN_bn2hex() and BN_bn2dec() return printable strings containing the
50 hexadecimal and decimal encoding of B<a> respectively. For negative
51 numbers, the string is prefaced with a leading '-'. The string must be
52 freed later using OPENSSL_free().
54 BN_hex2bn() converts the string B<str> containing a hexadecimal number
55 to a B<BIGNUM> and stores it in **B<bn>. If *B<bn> is NULL, a new
56 B<BIGNUM> is created. If B<bn> is NULL, it only computes the number's
57 length in hexadecimal digits. If the string starts with '-', the
58 number is negative. BN_dec2bn() is the same using the decimal system.
60 BN_print() and BN_print_fp() write the hexadecimal encoding of B<a>,
61 with a leading '-' for negative numbers, to the B<BIO> or B<FILE>
64 BN_bn2mpi() and BN_mpi2bn() convert B<BIGNUM>s from and to a format
65 that consists of the number's length in bytes represented as a 4-byte
66 big-endian number, and the number itself in big-endian format, where
67 the most significant bit signals a negative number (the representation
68 of numbers with the MSB set is prefixed with null byte).
70 BN_bn2mpi() stores the representation of B<a> at B<to>, where B<to>
71 must be large enough to hold the result. The size can be determined by
72 calling BN_bn2mpi(B<a>, NULL).
74 BN_mpi2bn() converts the B<len> bytes long representation at B<s> to
75 a B<BIGNUM> and stores it at B<ret>, or in a newly allocated B<BIGNUM>
80 BN_bn2bin() returns the length of the big-endian number placed at B<to>.
81 BN_bin2bn() returns the B<BIGNUM>, NULL on error.
83 BN_bn2binpad() returns the number of bytes written or -1 if the supplied
86 BN_bn2hex() and BN_bn2dec() return a null-terminated string, or NULL
87 on error. BN_hex2bn() and BN_dec2bn() return the number's length in
88 hexadecimal or decimal digits, and 0 on error.
90 BN_print_fp() and BN_print() return 1 on success, 0 on write errors.
92 BN_bn2mpi() returns the length of the representation. BN_mpi2bn()
93 returns the B<BIGNUM>, and NULL on error.
95 The error codes can be obtained by L<ERR_get_error(3)>.
99 L<bn(3)>, L<ERR_get_error(3)>, L<BN_zero(3)>,
100 L<ASN1_INTEGER_to_BN(3)>,