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4486d0cd UM |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
aafbe1cc | 5 | DH_generate_parameters_ex, DH_generate_parameters, |
b0004708 PY |
6 | DH_check, DH_check_params, |
7 | DH_check_ex, DH_check_params_ex, DH_check_pub_key_ex | |
8 | - generate and check Diffie-Hellman | |
6f8950a3 | 9 | parameters |
4486d0cd UM |
10 | |
11 | =head1 SYNOPSIS | |
12 | ||
13 | #include <openssl/dh.h> | |
14 | ||
aebb9aac | 15 | int DH_generate_parameters_ex(DH *dh, int prime_len, int generator, BN_GENCB *cb); |
4486d0cd UM |
16 | |
17 | int DH_check(DH *dh, int *codes); | |
6f8950a3 | 18 | int DH_check_params(DH *dh, int *codes); |
4486d0cd | 19 | |
b0004708 PY |
20 | int DH_check_ex(const DH *dh); |
21 | int DH_check_params_ex(const DH *dh); | |
22 | int DH_check_pub_key_ex(const DH *dh, const BIGNUM *pub_key); | |
23 | ||
aafbe1cc MC |
24 | Deprecated: |
25 | ||
98186eb4 | 26 | #if OPENSSL_API_COMPAT < 0x00908000L |
aafbe1cc | 27 | DH *DH_generate_parameters(int prime_len, int generator, |
e9b77246 | 28 | void (*callback)(int, int, void *), void *cb_arg); |
98186eb4 | 29 | #endif |
aafbe1cc | 30 | |
4486d0cd UM |
31 | =head1 DESCRIPTION |
32 | ||
aafbe1cc MC |
33 | DH_generate_parameters_ex() generates Diffie-Hellman parameters that can |
34 | be shared among a group of users, and stores them in the provided B<DH> | |
35 | structure. The pseudo-random number generator must be | |
b3696a55 RS |
36 | seeded before calling it. |
37 | The parameters generated by DH_generate_parameters_ex() should not be used in | |
38 | signature schemes. | |
4486d0cd UM |
39 | |
40 | B<prime_len> is the length in bits of the safe prime to be generated. | |
1bc74519 | 41 | B<generator> is a small number E<gt> 1, typically 2 or 5. |
4486d0cd UM |
42 | |
43 | A callback function may be used to provide feedback about the progress | |
aafbe1cc | 44 | of the key generation. If B<cb> is not B<NULL>, it will be |
9b86974e | 45 | called as described in L<BN_generate_prime(3)> while a random prime |
aafbe1cc | 46 | number is generated, and when a prime has been found, B<BN_GENCB_call(cb, 3, 0)> |
b3696a55 | 47 | is called. See L<BN_generate_prime_ex(3)> for information on |
aafbe1cc | 48 | the BN_GENCB_call() function. |
4486d0cd | 49 | |
b3696a55 RS |
50 | DH_generate_parameters() is similar to DH_generate_prime_ex() but |
51 | expects an old-style callback function; see | |
52 | L<BN_generate_prime(3)> for information on the old-style callback. | |
53 | ||
6f8950a3 RL |
54 | DH_check_params() confirms that the B<p> and B<g> are likely enough to |
55 | be valid. | |
56 | This is a lightweight check, if a more thorough check is needed, use | |
57 | DH_check(). | |
58 | The value of B<*codes> is updated with any problems found. | |
59 | If B<*codes> is zero then no problems were found, otherwise the | |
60 | following bits may be set: | |
61 | ||
62 | =over 4 | |
63 | ||
64 | =item DH_CHECK_P_NOT_PRIME | |
65 | ||
66 | The parameter B<p> has been determined to not being an odd prime. | |
67 | Note that the lack of this bit doesn't guarantee that B<p> is a | |
68 | prime. | |
69 | ||
70 | =item DH_NOT_SUITABLE_GENERATOR | |
71 | ||
72 | The generator B<g> is not suitable. | |
73 | Note that the lack of this bit doesn't guarantee that B<g> is | |
74 | suitable, unless B<p> is known to be a strong prime. | |
75 | ||
76 | =back | |
77 | ||
eeb21772 MC |
78 | DH_check() confirms that the Diffie-Hellman parameters B<dh> are valid. The |
79 | value of B<*codes> is updated with any problems found. If B<*codes> is zero then | |
80 | no problems were found, otherwise the following bits may be set: | |
81 | ||
82 | =over 4 | |
83 | ||
84 | =item DH_CHECK_P_NOT_PRIME | |
85 | ||
86 | The parameter B<p> is not prime. | |
87 | ||
88 | =item DH_CHECK_P_NOT_SAFE_PRIME | |
89 | ||
90 | The parameter B<p> is not a safe prime and no B<q> value is present. | |
91 | ||
92 | =item DH_UNABLE_TO_CHECK_GENERATOR | |
93 | ||
94 | The generator B<g> cannot be checked for suitability. | |
95 | ||
96 | =item DH_NOT_SUITABLE_GENERATOR | |
97 | ||
98 | The generator B<g> is not suitable. | |
99 | ||
100 | =item DH_CHECK_Q_NOT_PRIME | |
101 | ||
102 | The parameter B<q> is not prime. | |
103 | ||
104 | =item DH_CHECK_INVALID_Q_VALUE | |
105 | ||
106 | The parameter B<q> is invalid. | |
107 | ||
108 | =item DH_CHECK_INVALID_J_VALUE | |
109 | ||
110 | The parameter B<j> is invalid. | |
111 | ||
112 | =back | |
4486d0cd | 113 | |
b0004708 PY |
114 | DH_check_ex(), DH_check_params() and DH_check_pub_key_ex() are similiar with |
115 | DH_check() and DH_check_params() respectively, but the error reasons are set | |
116 | to the OpenSSL error handling framework instead of returning by the function | |
117 | parameters. | |
118 | ||
4486d0cd UM |
119 | =head1 RETURN VALUES |
120 | ||
6f8950a3 RL |
121 | DH_generate_parameters_ex(), DH_check() and DH_check_params() return 1 |
122 | if the check could be performed, 0 otherwise. | |
aafbe1cc | 123 | |
b3696a55 RS |
124 | DH_generate_parameters() returns a pointer to the DH structure or NULL if |
125 | the parameter generation fails. | |
4486d0cd | 126 | |
b0004708 PY |
127 | DH_check_ex(), DH_check_params() and DH_check_pub_key_ex() return 1 if the |
128 | check is successful, 0 for failed. | |
129 | ||
9b86974e | 130 | The error codes can be obtained by L<ERR_get_error(3)>. |
4486d0cd | 131 | |
4486d0cd UM |
132 | =head1 SEE ALSO |
133 | ||
b97fdb57 | 134 | L<DH_new(3)>, L<ERR_get_error(3)>, L<RAND_bytes(3)>, |
9b86974e | 135 | L<DH_free(3)> |
4486d0cd | 136 | |
b3696a55 RS |
137 | =head1 HISTORY |
138 | ||
02eca5c6 | 139 | DH_generate_parameters() was deprecated in OpenSSL 0.9.8; use |
b3696a55 RS |
140 | DH_generate_parameters_ex() instead. |
141 | ||
e2f92610 RS |
142 | =head1 COPYRIGHT |
143 | ||
b0004708 | 144 | Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved. |
e2f92610 RS |
145 | |
146 | Licensed under the OpenSSL license (the "License"). You may not use | |
147 | this file except in compliance with the License. You can obtain a copy | |
148 | in the file LICENSE in the source distribution or at | |
149 | L<https://www.openssl.org/source/license.html>. | |
150 | ||
151 | =cut |