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dd8dec69 UM |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
c952780c | 5 | BN_bn2binpad, |
85a4807f DSH |
6 | BN_bn2bin, BN_bin2bn, BN_bn2lebinpad, BN_lebin2bn, BN_bn2hex, BN_bn2dec, |
7 | BN_hex2bn, BN_dec2bn, BN_print, BN_print_fp, BN_bn2mpi, | |
8 | BN_mpi2bn - format conversions | |
dd8dec69 UM |
9 | |
10 | =head1 SYNOPSIS | |
11 | ||
12 | #include <openssl/bn.h> | |
13 | ||
14 | int BN_bn2bin(const BIGNUM *a, unsigned char *to); | |
85a4807f | 15 | int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen); |
dd8dec69 UM |
16 | BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret); |
17 | ||
85a4807f DSH |
18 | int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen); |
19 | BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret); | |
20 | ||
dd8dec69 UM |
21 | char *BN_bn2hex(const BIGNUM *a); |
22 | char *BN_bn2dec(const BIGNUM *a); | |
23 | int BN_hex2bn(BIGNUM **a, const char *str); | |
24 | int BN_dec2bn(BIGNUM **a, const char *str); | |
25 | ||
dd8dec69 | 26 | int BN_print(BIO *fp, const BIGNUM *a); |
e93f9a32 | 27 | int BN_print_fp(FILE *fp, const BIGNUM *a); |
dd8dec69 UM |
28 | |
29 | int BN_bn2mpi(const BIGNUM *a, unsigned char *to); | |
30 | BIGNUM *BN_mpi2bn(unsigned char *s, int len, BIGNUM *ret); | |
31 | ||
32 | =head1 DESCRIPTION | |
33 | ||
34 | BN_bn2bin() converts the absolute value of B<a> into big-endian form | |
35 | and stores it at B<to>. B<to> must point to BN_num_bytes(B<a>) bytes of | |
36 | memory. | |
37 | ||
85a4807f DSH |
38 | BN_bn2binpad() also converts the absolute value of B<a> into big-endian form |
39 | and stores it at B<to>. B<tolen> indicates the length of the output buffer | |
40 | B<to>. The result is padded with zeroes if necessary. If B<tolen> is less than | |
41 | BN_num_bytes(B<a>) an error is returned. | |
42 | ||
dd8dec69 UM |
43 | BN_bin2bn() converts the positive integer in big-endian form of length |
44 | B<len> at B<s> into a B<BIGNUM> and places it in B<ret>. If B<ret> is | |
45 | NULL, a new B<BIGNUM> is created. | |
46 | ||
aeb3e4ab | 47 | BN_bn2lebinpad() and BN_lebin2bn() are identical to BN_bn2binpad() and |
85a4807f DSH |
48 | BN_bin2bn() except the buffer is in little-endian format. |
49 | ||
dd8dec69 UM |
50 | BN_bn2hex() and BN_bn2dec() return printable strings containing the |
51 | hexadecimal and decimal encoding of B<a> respectively. For negative | |
52 | numbers, the string is prefaced with a leading '-'. The string must be | |
18edda0f | 53 | freed later using OPENSSL_free(). |
dd8dec69 | 54 | |
14f46560 | 55 | BN_hex2bn() takes as many characters as possible from the string B<str>, |
5e0dc5c9 | 56 | including the leading character '-' which means negative, to form a valid |
57 | hexadecimal number representation and converts them to a B<BIGNUM> and | |
58 | stores it in **B<bn>. If *B<bn> is NULL, a new B<BIGNUM> is created. If | |
59 | B<bn> is NULL, it only computes the length of valid representation. | |
01c09f9f | 60 | A "negative zero" is converted to zero. |
5e0dc5c9 | 61 | BN_dec2bn() is the same using the decimal system. |
dd8dec69 | 62 | |
223fc865 UM |
63 | BN_print() and BN_print_fp() write the hexadecimal encoding of B<a>, |
64 | with a leading '-' for negative numbers, to the B<BIO> or B<FILE> | |
dd8dec69 UM |
65 | B<fp>. |
66 | ||
67 | BN_bn2mpi() and BN_mpi2bn() convert B<BIGNUM>s from and to a format | |
4e9ef338 | 68 | that consists of the number's length in bytes represented as a 4-byte |
dd8dec69 UM |
69 | big-endian number, and the number itself in big-endian format, where |
70 | the most significant bit signals a negative number (the representation | |
71 | of numbers with the MSB set is prefixed with null byte). | |
72 | ||
73 | BN_bn2mpi() stores the representation of B<a> at B<to>, where B<to> | |
74 | must be large enough to hold the result. The size can be determined by | |
75 | calling BN_bn2mpi(B<a>, NULL). | |
76 | ||
77 | BN_mpi2bn() converts the B<len> bytes long representation at B<s> to | |
e93f9a32 | 78 | a B<BIGNUM> and stores it at B<ret>, or in a newly allocated B<BIGNUM> |
dd8dec69 UM |
79 | if B<ret> is NULL. |
80 | ||
81 | =head1 RETURN VALUES | |
82 | ||
83 | BN_bn2bin() returns the length of the big-endian number placed at B<to>. | |
84 | BN_bin2bn() returns the B<BIGNUM>, NULL on error. | |
85 | ||
85a4807f DSH |
86 | BN_bn2binpad() returns the number of bytes written or -1 if the supplied |
87 | buffer is too small. | |
88 | ||
dd8dec69 | 89 | BN_bn2hex() and BN_bn2dec() return a null-terminated string, or NULL |
a130950d RS |
90 | on error. BN_hex2bn() and BN_dec2bn() return the number of characters |
91 | used in parsing, or 0 on error, in which | |
5e0dc5c9 | 92 | case no new B<BIGNUM> will be created. |
dd8dec69 UM |
93 | |
94 | BN_print_fp() and BN_print() return 1 on success, 0 on write errors. | |
95 | ||
96 | BN_bn2mpi() returns the length of the representation. BN_mpi2bn() | |
97 | returns the B<BIGNUM>, and NULL on error. | |
98 | ||
9b86974e | 99 | The error codes can be obtained by L<ERR_get_error(3)>. |
dd8dec69 UM |
100 | |
101 | =head1 SEE ALSO | |
102 | ||
9e183d22 | 103 | L<ERR_get_error(3)>, L<BN_zero(3)>, |
9b86974e RS |
104 | L<ASN1_INTEGER_to_BN(3)>, |
105 | L<BN_num_bytes(3)> | |
dd8dec69 | 106 | |
e2f92610 RS |
107 | =head1 COPYRIGHT |
108 | ||
9e183d22 | 109 | Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved. |
e2f92610 RS |
110 | |
111 | Licensed under the OpenSSL license (the "License"). You may not use | |
112 | this file except in compliance with the License. You can obtain a copy | |
113 | in the file LICENSE in the source distribution or at | |
114 | L<https://www.openssl.org/source/license.html>. | |
115 | ||
116 | =cut |