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1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
4d524e10 | 5 | DH_generate_key, DH_compute_key - perform Diffie-Hellman key exchange |
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6 | |
7 | =head1 SYNOPSIS | |
8 | ||
9 | #include <openssl/dh.h> | |
10 | ||
11 | int DH_generate_key(DH *dh); | |
12 | ||
13 | int DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh); | |
14 | ||
15 | =head1 DESCRIPTION | |
16 | ||
17 | DH_generate_key() performs the first step of a Diffie-Hellman key | |
18 | exchange by generating private and public DH values. By calling | |
19 | DH_compute_key(), these are combined with the other party's public | |
20 | value to compute the shared key. | |
21 | ||
22 | DH_generate_key() expects B<dh> to contain the shared parameters | |
23 | B<dh-E<gt>p> and B<dh-E<gt>g>. It generates a random private DH value | |
924875e5 BM |
24 | unless B<dh-E<gt>priv_key> is already set, and computes the |
25 | corresponding public value B<dh-E<gt>pub_key>, which can then be | |
26 | published. | |
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27 | |
28 | DH_compute_key() computes the shared secret from the private DH value | |
29 | in B<dh> and the other party's public value in B<pub_key> and stores | |
30 | it in B<key>. B<key> must point to B<DH_size(dh)> bytes of memory. | |
31 | ||
32 | =head1 RETURN VALUES | |
33 | ||
34 | DH_generate_key() returns 1 on success, 0 otherwise. | |
35 | ||
36 | DH_compute_key() returns the size of the shared secret on success, -1 | |
37 | on error. | |
38 | ||
bb075f88 | 39 | The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>. |
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40 | |
41 | =head1 SEE ALSO | |
42 | ||
6859cf74 | 43 | L<dh(3)|dh(3)>, L<ERR_get_error(3)|ERR_get_error(3)>, L<rand(3)|rand(3)>, L<DH_size(3)|DH_size(3)> |
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44 | |
45 | =head1 HISTORY | |
46 | ||
47 | DH_generate_key() and DH_compute_key() are available in all versions | |
48 | of SSLeay and OpenSSL. | |
49 | ||
50 | =cut |