1 =pod 2 3 =head1 NAME 4 5 DSA_set_default_method, DSA_get_default_method, 6 DSA_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 24 A B<DSA_METHOD> specifies the functions that OpenSSL uses for DSA 25 operations. By modifying the method, alternative implementations 26 such as hardware accelerators may be used. IMPORTANT: See the NOTES section for 27 important information about how these DSA API functions are affected by the use 28 of B<ENGINE> API calls. 29 30 Initially, the default DSA_METHOD is the OpenSSL internal implementation, 31 as returned by DSA_OpenSSL(). 32 33 DSA_set_default_method() makes B<meth> the default method for all DSA 34 structures created later. 35 B<NB>: This is true only whilst no ENGINE has 36 been set as a default for DSA, so this function is no longer recommended. 37 This function is not thread-safe and should not be called at the same time 38 as other OpenSSL functions. 39 40 DSA_get_default_method() returns a pointer to the current default 41 DSA_METHOD. However, the meaningfulness of this result is dependent on 42 whether the ENGINE API is being used, so this function is no longer 43 recommended. 44 45 DSA_set_method() selects B<meth> to perform all operations using the key 46 B<rsa>. This will replace the DSA_METHOD used by the DSA key and if the 47 previous method was supplied by an ENGINE, the handle to that ENGINE will 48 be released during the change. It is possible to have DSA keys that only 49 work with certain DSA_METHOD implementations (e.g. from an ENGINE module 50 that supports embedded hardware-protected keys), and in such cases 51 attempting to change the DSA_METHOD for the key can have unexpected 52 results. See L<DSA_meth_new> for information on constructing custom DSA_METHOD 53 objects; 54 55 DSA_new_method() allocates and initializes a DSA structure so that B<engine> 56 will be used for the DSA operations. If B<engine> is NULL, the default engine 57 for DSA operations is used, and if no default ENGINE is set, the DSA_METHOD 58 controlled by DSA_set_default_method() is used. 59 60 =head1 RETURN VALUES 61 62 DSA_OpenSSL() and DSA_get_default_method() return pointers to the respective 63 B<DSA_METHOD>s. 64 65 DSA_set_default_method() returns no value. 66 67 DSA_set_method() returns nonzero if the provided B<meth> was successfully set as 68 the method for B<dsa> (including unloading the ENGINE handle if the previous 69 method was supplied by an ENGINE). 70 71 DSA_new_method() returns NULL and sets an error code that can be 72 obtained by L<ERR_get_error(3)> if the allocation 73 fails. Otherwise it returns a pointer to the newly allocated structure. 74 75 =head1 SEE ALSO 76 77 L<DSA_new(3)>, L<DSA_new(3)>, L<DSA_meth_new(3)> 78 79 =head1 COPYRIGHT 80 81 Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved. 82 83 Licensed under the OpenSSL license (the "License"). You may not use 84 this file except in compliance with the License. You can obtain a copy 85 in the file LICENSE in the source distribution or at 86 L<https://www.openssl.org/source/license.html>. 87 88 =cut 89