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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, | |
4d524e10 | 6 | BN_print, BN_print_fp, BN_bn2mpi, BN_mpi2bn - format conversions |
dd8dec69 UM |
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 | ||
dd8dec69 | 20 | int BN_print(BIO *fp, const BIGNUM *a); |
e93f9a32 | 21 | int BN_print_fp(FILE *fp, const BIGNUM *a); |
dd8dec69 UM |
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 | |
18edda0f | 39 | freed later using OPENSSL_free(). |
dd8dec69 UM |
40 | |
41 | BN_hex2bn() converts the string B<str> containing a hexadecimal number | |
3d5d123d AP |
42 | to a B<BIGNUM> and stores it in **B<a>. If *B<a> is NULL, a new |
43 | B<BIGNUM> is created. If B<a> is NULL, it only computes the number's | |
dd8dec69 | 44 | length in hexadecimal digits. If the string starts with '-', the |
3f101496 RS |
45 | number is negative. |
46 | A "negative zero" is converted to zero. | |
47 | BN_dec2bn() is the same using the decimal system. | |
dd8dec69 | 48 | |
223fc865 UM |
49 | BN_print() and BN_print_fp() write the hexadecimal encoding of B<a>, |
50 | with a leading '-' for negative numbers, to the B<BIO> or B<FILE> | |
dd8dec69 UM |
51 | B<fp>. |
52 | ||
53 | BN_bn2mpi() and BN_mpi2bn() convert B<BIGNUM>s from and to a format | |
4e9ef338 | 54 | that consists of the number's length in bytes represented as a 4-byte |
dd8dec69 UM |
55 | big-endian number, and the number itself in big-endian format, where |
56 | the most significant bit signals a negative number (the representation | |
57 | of numbers with the MSB set is prefixed with null byte). | |
58 | ||
59 | BN_bn2mpi() stores the representation of B<a> at B<to>, where B<to> | |
60 | must be large enough to hold the result. The size can be determined by | |
61 | calling BN_bn2mpi(B<a>, NULL). | |
62 | ||
63 | BN_mpi2bn() converts the B<len> bytes long representation at B<s> to | |
e93f9a32 | 64 | a B<BIGNUM> and stores it at B<ret>, or in a newly allocated B<BIGNUM> |
dd8dec69 UM |
65 | if B<ret> is NULL. |
66 | ||
67 | =head1 RETURN VALUES | |
68 | ||
69 | BN_bn2bin() returns the length of the big-endian number placed at B<to>. | |
70 | BN_bin2bn() returns the B<BIGNUM>, NULL on error. | |
71 | ||
72 | BN_bn2hex() and BN_bn2dec() return a null-terminated string, or NULL | |
c0f4a556 RS |
73 | on error. BN_hex2bn() and BN_dec2bn() return the number of characters |
74 | used in parsing, or 0 on error, in which | |
75 | case no new B<BIGNUM> will be created. | |
dd8dec69 UM |
76 | |
77 | BN_print_fp() and BN_print() return 1 on success, 0 on write errors. | |
78 | ||
79 | BN_bn2mpi() returns the length of the representation. BN_mpi2bn() | |
80 | returns the B<BIGNUM>, and NULL on error. | |
81 | ||
bb075f88 | 82 | The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>. |
dd8dec69 UM |
83 | |
84 | =head1 SEE ALSO | |
85 | ||
6859cf74 | 86 | L<bn(3)|bn(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<BN_zero(3)|BN_zero(3)>, |
bb075f88 RL |
87 | L<ASN1_INTEGER_to_BN(3)|ASN1_INTEGER_to_BN(3)>, |
88 | L<BN_num_bytes(3)|BN_num_bytes(3)> | |
dd8dec69 UM |
89 | |
90 | =head1 HISTORY | |
91 | ||
92 | BN_bn2bin(), BN_bin2bn(), BN_print_fp() and BN_print() are available | |
93 | in all versions of SSLeay and OpenSSL. | |
94 | ||
95 | BN_bn2hex(), BN_bn2dec(), BN_hex2bn(), BN_dec2bn(), BN_bn2mpi() and | |
96 | BN_mpi2bn() were added in SSLeay 0.9.0. | |
97 | ||
98 | =cut |