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 12 void DSA_set_default_method(const DSA_METHOD *meth); 13 14 const DSA_METHOD *DSA_get_default_method(void); 15 16 int DSA_set_method(DSA *dsa, const DSA_METHOD *meth); 17 18 DSA *DSA_new_method(ENGINE *engine); 19 20 DSA_METHOD *DSA_OpenSSL(void); 21 22=head1 DESCRIPTION 23 24A B<DSA_METHOD> specifies the functions that OpenSSL uses for DSA 25operations. By modifying the method, alternative implementations 26such as hardware accelerators may be used. IMPORTANT: See the NOTES section for 27important information about how these DSA API functions are affected by the use 28of B<ENGINE> API calls. 29 30Initially, the default DSA_METHOD is the OpenSSL internal implementation, 31as returned by DSA_OpenSSL(). 32 33DSA_set_default_method() makes B<meth> the default method for all DSA 34structures created later. 35B<NB>: This is true only whilst no ENGINE has 36been set as a default for DSA, so this function is no longer recommended. 37This function is not thread-safe and should not be called at the same time 38as other OpenSSL functions. 39 40DSA_get_default_method() returns a pointer to the current default 41DSA_METHOD. However, the meaningfulness of this result is dependent on 42whether the ENGINE API is being used, so this function is no longer 43recommended. 44 45DSA_set_method() selects B<meth> to perform all operations using the key 46B<rsa>. This will replace the DSA_METHOD used by the DSA key and if the 47previous method was supplied by an ENGINE, the handle to that ENGINE will 48be released during the change. It is possible to have DSA keys that only 49work with certain DSA_METHOD implementations (e.g. from an ENGINE module 50that supports embedded hardware-protected keys), and in such cases 51attempting to change the DSA_METHOD for the key can have unexpected 52results. See L<DSA_meth_new> for information on constructing custom DSA_METHOD 53objects; 54 55DSA_new_method() allocates and initializes a DSA structure so that B<engine> 56will be used for the DSA operations. If B<engine> is NULL, the default engine 57for DSA operations is used, and if no default ENGINE is set, the DSA_METHOD 58controlled by DSA_set_default_method() is used. 59 60=head1 RETURN VALUES 61 62DSA_OpenSSL() and DSA_get_default_method() return pointers to the respective 63B<DSA_METHOD>s. 64 65DSA_set_default_method() returns no value. 66 67DSA_set_method() returns nonzero if the provided B<meth> was successfully set as 68the method for B<dsa> (including unloading the ENGINE handle if the previous 69method was supplied by an ENGINE). 70 71DSA_new_method() returns NULL and sets an error code that can be 72obtained by L<ERR_get_error(3)> if the allocation 73fails. Otherwise it returns a pointer to the newly allocated structure. 74 75=head1 SEE ALSO 76 77L<DSA_new(3)>, L<DSA_new(3)>, L<DSA_meth_new(3)> 78 79=head1 COPYRIGHT 80 81Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved. 82 83Licensed under the OpenSSL license (the "License"). You may not use 84this file except in compliance with the License. You can obtain a copy 85in the file LICENSE in the source distribution or at 86L<https://www.openssl.org/source/license.html>. 87 88=cut 89