xref: /openssl/doc/man3/DSA_set_method.pod (revision 3dbf8243)
1=pod
2
3=head1 NAME
4
5DSA_set_default_method, DSA_get_default_method,
6DSA_set_method, DSA_new_method, DSA_OpenSSL - select DSA method
7
8=head1 SYNOPSIS
9
10 #include <openssl/dsa.h>
11
12The following functions have been deprecated since OpenSSL 3.0, and can be
13hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
14see L<openssl_user_macros(7)>:
15
16 void DSA_set_default_method(const DSA_METHOD *meth);
17
18 const DSA_METHOD *DSA_get_default_method(void);
19
20 int DSA_set_method(DSA *dsa, const DSA_METHOD *meth);
21
22 DSA *DSA_new_method(ENGINE *engine);
23
24 const DSA_METHOD *DSA_OpenSSL(void);
25
26=head1 DESCRIPTION
27
28All of the functions described on this page are deprecated.
29Applications should providers instead of method overrides.
30
31A B<DSA_METHOD> specifies the functions that OpenSSL uses for DSA
32operations. By modifying the method, alternative implementations
33such as hardware accelerators may be used. IMPORTANT: See the NOTES section for
34important information about how these DSA API functions are affected by the use
35of B<ENGINE> API calls.
36
37Initially, the default DSA_METHOD is the OpenSSL internal implementation,
38as returned by DSA_OpenSSL().
39
40DSA_set_default_method() makes B<meth> the default method for all DSA
41structures created later.
42B<NB>: This is true only whilst no ENGINE has
43been set as a default for DSA, so this function is no longer recommended.
44This function is not thread-safe and should not be called at the same time
45as other OpenSSL functions.
46
47DSA_get_default_method() returns a pointer to the current default
48DSA_METHOD. However, the meaningfulness of this result is dependent on
49whether the ENGINE API is being used, so this function is no longer
50recommended.
51
52DSA_set_method() selects B<meth> to perform all operations using the key
53B<rsa>. This will replace the DSA_METHOD used by the DSA key and if the
54previous method was supplied by an ENGINE, the handle to that ENGINE will
55be released during the change. It is possible to have DSA keys that only
56work with certain DSA_METHOD implementations (e.g. from an ENGINE module
57that supports embedded hardware-protected keys), and in such cases
58attempting to change the DSA_METHOD for the key can have unexpected
59results. See L<DSA_meth_new(3)> for information on constructing custom DSA_METHOD
60objects;
61
62DSA_new_method() allocates and initializes a DSA structure so that B<engine>
63will be used for the DSA operations. If B<engine> is NULL, the default engine
64for DSA operations is used, and if no default ENGINE is set, the DSA_METHOD
65controlled by DSA_set_default_method() is used.
66
67=head1 RETURN VALUES
68
69DSA_OpenSSL() and DSA_get_default_method() return pointers to the respective
70B<DSA_METHOD>s.
71
72DSA_set_default_method() returns no value.
73
74DSA_set_method() returns nonzero if the provided B<meth> was successfully set as
75the method for B<dsa> (including unloading the ENGINE handle if the previous
76method was supplied by an ENGINE).
77
78DSA_new_method() returns NULL and sets an error code that can be
79obtained by L<ERR_get_error(3)> if the allocation
80fails. Otherwise it returns a pointer to the newly allocated structure.
81
82=head1 SEE ALSO
83
84L<DSA_new(3)>, L<DSA_new(3)>, L<DSA_meth_new(3)>
85
86=head1 HISTORY
87
88All of these functions were deprecated in OpenSSL 3.0.
89
90=head1 COPYRIGHT
91
92Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
93
94Licensed under the Apache License 2.0 (the "License").  You may not use
95this file except in compliance with the License.  You can obtain a copy
96in the file LICENSE in the source distribution or at
97L<https://www.openssl.org/source/license.html>.
98
99=cut
100