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dd8dec69 UM |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
5 | BN_bn2bin, BN_bin2bn, BN_bn2hex, BN_bn2dec, BN_hex2bn, BN_dec2bn, | |
6 | BN_print_fp, BN_print, BN_bn2mpi, BN_mpi2bn - Format conversions | |
7 | ||
8 | =head1 SYNOPSIS | |
9 | ||
10 | #include <openssl/bn.h> | |
11 | ||
12 | int BN_bn2bin(const BIGNUM *a, unsigned char *to); | |
13 | BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret); | |
14 | ||
15 | char *BN_bn2hex(const BIGNUM *a); | |
16 | char *BN_bn2dec(const BIGNUM *a); | |
17 | int BN_hex2bn(BIGNUM **a, const char *str); | |
18 | int BN_dec2bn(BIGNUM **a, const char *str); | |
19 | ||
20 | int BN_print_fp(FILE *fp, BIGNUM *a); | |
21 | int BN_print(BIO *fp, const BIGNUM *a); | |
22 | ||
23 | int BN_bn2mpi(const BIGNUM *a, unsigned char *to); | |
24 | BIGNUM *BN_mpi2bn(unsigned char *s, int len, BIGNUM *ret); | |
25 | ||
26 | =head1 DESCRIPTION | |
27 | ||
28 | BN_bn2bin() converts the absolute value of B<a> into big-endian form | |
29 | and stores it at B<to>. B<to> must point to BN_num_bytes(B<a>) bytes of | |
30 | memory. | |
31 | ||
32 | BN_bin2bn() converts the positive integer in big-endian form of length | |
33 | B<len> at B<s> into a B<BIGNUM> and places it in B<ret>. If B<ret> is | |
34 | NULL, a new B<BIGNUM> is created. | |
35 | ||
36 | BN_bn2hex() and BN_bn2dec() return printable strings containing the | |
37 | hexadecimal and decimal encoding of B<a> respectively. For negative | |
38 | numbers, the string is prefaced with a leading '-'. The string must be | |
39 | Free()d later. | |
40 | ||
41 | BN_hex2bn() converts the string B<str> containing a hexadecimal number | |
42 | to a B<BIGNUM> and stores it in **B<bn>. If *B<bn> is NULL, a new | |
43 | B<BIGNUM> is created. If B<bn> is NULL, it only computes the number's | |
44 | length in hexadecimal digits. If the string starts with '-', the | |
45 | number is negative. BN_dec2bn() is the same using the decimal system. | |
46 | ||
47 | BN_print_fp() and BN_print() write the hexadecimal encoding of B<a>, | |
48 | with a leading '-' for negative numbers, to the B<FILE> or B<BIO> | |
49 | B<fp>. | |
50 | ||
51 | BN_bn2mpi() and BN_mpi2bn() convert B<BIGNUM>s from and to a format | |
52 | that consists of the number's length in bytes represented as a 3-byte | |
53 | big-endian number, and the number itself in big-endian format, where | |
54 | the most significant bit signals a negative number (the representation | |
55 | of numbers with the MSB set is prefixed with null byte). | |
56 | ||
57 | BN_bn2mpi() stores the representation of B<a> at B<to>, where B<to> | |
58 | must be large enough to hold the result. The size can be determined by | |
59 | calling BN_bn2mpi(B<a>, NULL). | |
60 | ||
61 | BN_mpi2bn() converts the B<len> bytes long representation at B<s> to | |
62 | a B<BIGNUM> and stores it ar B<ret>, or in a newly allocated B<BIGNUM> | |
63 | if B<ret> is NULL. | |
64 | ||
65 | =head1 RETURN VALUES | |
66 | ||
67 | BN_bn2bin() returns the length of the big-endian number placed at B<to>. | |
68 | BN_bin2bn() returns the B<BIGNUM>, NULL on error. | |
69 | ||
70 | BN_bn2hex() and BN_bn2dec() return a null-terminated string, or NULL | |
71 | on error. BN_hex2bn() and BN_dec2bn() return the number's length in | |
72 | hexadecimal or decimal digits, and 0 on error. | |
73 | ||
74 | BN_print_fp() and BN_print() return 1 on success, 0 on write errors. | |
75 | ||
76 | BN_bn2mpi() returns the length of the representation. BN_mpi2bn() | |
77 | returns the B<BIGNUM>, and NULL on error. | |
78 | ||
79 | The error codes can be obtained by ERR_get_error(3). | |
80 | ||
81 | =head1 SEE ALSO | |
82 | ||
83 | bn(3), err(3), BN_zero(3), ASN1_INTEGER_to_BN(3), BN_num_bytes(3) | |
84 | ||
85 | =head1 HISTORY | |
86 | ||
87 | BN_bn2bin(), BN_bin2bn(), BN_print_fp() and BN_print() are available | |
88 | in all versions of SSLeay and OpenSSL. | |
89 | ||
90 | BN_bn2hex(), BN_bn2dec(), BN_hex2bn(), BN_dec2bn(), BN_bn2mpi() and | |
91 | BN_mpi2bn() were added in SSLeay 0.9.0. | |
92 | ||
93 | =cut |