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dd8dec69 UM |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
85a4807f DSH |
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 | |
dd8dec69 UM |
8 | |
9 | =head1 SYNOPSIS | |
10 | ||
11 | #include <openssl/bn.h> | |
12 | ||
13 | int BN_bn2bin(const BIGNUM *a, unsigned char *to); | |
85a4807f | 14 | int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen); |
dd8dec69 UM |
15 | BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret); |
16 | ||
85a4807f DSH |
17 | int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen); |
18 | BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret); | |
19 | ||
dd8dec69 UM |
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); | |
24 | ||
dd8dec69 | 25 | int BN_print(BIO *fp, const BIGNUM *a); |
e93f9a32 | 26 | int BN_print_fp(FILE *fp, const BIGNUM *a); |
dd8dec69 UM |
27 | |
28 | int BN_bn2mpi(const BIGNUM *a, unsigned char *to); | |
29 | BIGNUM *BN_mpi2bn(unsigned char *s, int len, BIGNUM *ret); | |
30 | ||
31 | =head1 DESCRIPTION | |
32 | ||
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 | |
35 | memory. | |
36 | ||
85a4807f DSH |
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. | |
41 | ||
dd8dec69 UM |
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. | |
45 | ||
85a4807f DSH |
46 | BN_bn2lebinpad() and BN_bin2lbn() are identical to BN_bn2binpad() and |
47 | BN_bin2bn() except the buffer is in little-endian format. | |
48 | ||
dd8dec69 UM |
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 | |
18edda0f | 52 | freed later using OPENSSL_free(). |
dd8dec69 UM |
53 | |
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. | |
59 | ||
223fc865 UM |
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> | |
dd8dec69 UM |
62 | B<fp>. |
63 | ||
64 | BN_bn2mpi() and BN_mpi2bn() convert B<BIGNUM>s from and to a format | |
4e9ef338 | 65 | that consists of the number's length in bytes represented as a 4-byte |
dd8dec69 UM |
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). | |
69 | ||
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). | |
73 | ||
74 | BN_mpi2bn() converts the B<len> bytes long representation at B<s> to | |
e93f9a32 | 75 | a B<BIGNUM> and stores it at B<ret>, or in a newly allocated B<BIGNUM> |
dd8dec69 UM |
76 | if B<ret> is NULL. |
77 | ||
78 | =head1 RETURN VALUES | |
79 | ||
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. | |
82 | ||
85a4807f DSH |
83 | BN_bn2binpad() returns the number of bytes written or -1 if the supplied |
84 | buffer is too small. | |
85 | ||
dd8dec69 UM |
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. | |
89 | ||
90 | BN_print_fp() and BN_print() return 1 on success, 0 on write errors. | |
91 | ||
92 | BN_bn2mpi() returns the length of the representation. BN_mpi2bn() | |
93 | returns the B<BIGNUM>, and NULL on error. | |
94 | ||
9b86974e | 95 | The error codes can be obtained by L<ERR_get_error(3)>. |
dd8dec69 UM |
96 | |
97 | =head1 SEE ALSO | |
98 | ||
9b86974e RS |
99 | L<bn(3)>, L<ERR_get_error(3)>, L<BN_zero(3)>, |
100 | L<ASN1_INTEGER_to_BN(3)>, | |
101 | L<BN_num_bytes(3)> | |
dd8dec69 | 102 | |
dd8dec69 | 103 | =cut |
e2f92610 RS |
104 | |
105 | =head1 COPYRIGHT | |
106 | ||
107 | Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. | |
108 | ||
109 | Licensed under the OpenSSL license (the "License"). You may not use | |
110 | this file except in compliance with the License. You can obtain a copy | |
111 | in the file LICENSE in the source distribution or at | |
112 | L<https://www.openssl.org/source/license.html>. | |
113 | ||
114 | =cut |