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=head1 NAME

DSA_set_default_method, DSA_get_default_method,
DSA_set_method, DSA_new_method, DSA_OpenSSL - select DSA method

=head1 SYNOPSIS

 #include <openssl/dsa.h>

The following functions have been deprecated since OpenSSL 3.0, and can be
hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
see L<openssl_user_macros(7)>:

 void DSA_set_default_method(const DSA_METHOD *meth);

 const DSA_METHOD *DSA_get_default_method(void);

 int DSA_set_method(DSA *dsa, const DSA_METHOD *meth);

 DSA *DSA_new_method(ENGINE *engine);

 const DSA_METHOD *DSA_OpenSSL(void);

=head1 DESCRIPTION

All of the functions described on this page are deprecated.
Applications should providers instead of method overrides.

A B<DSA_METHOD> specifies the functions that OpenSSL uses for DSA
operations. By modifying the method, alternative implementations
such as hardware accelerators may be used.

Initially, the default DSA_METHOD is the OpenSSL internal implementation,
as returned by DSA_OpenSSL().

DSA_set_default_method() makes B<meth> the default method for all DSA
structures created later.
B<NB>: This function is not thread-safe and should not be called at the same time
as other OpenSSL functions.

DSA_get_default_method() returns a pointer to the current default
DSA_METHOD.

DSA_set_method() selects B<meth> to perform all operations using the key
B<dsa>. This will replace the DSA_METHOD used by the DSA key.
It is possible to have DSA keys that only work with certain DSA_METHOD
implementations, and in such cases attempting to change the DSA_METHOD for the
key can have unexpected results. See L<DSA_meth_new(3)> for information on
constructing custom DSA_METHOD objects.

DSA_new_method() allocates and initializes a DSA structure so that the
DSA_METHOD controlled by DSA_set_default_method() is used. I<engine> B<must>
be NULL.

=head1 RETURN VALUES

DSA_OpenSSL() and DSA_get_default_method() return pointers to the respective
B<DSA_METHOD>s.

DSA_set_default_method() returns no value.

DSA_set_method() returns nonzero if the provided B<meth> was successfully set as
the method for B<dsa>.

DSA_new_method() returns NULL and sets an error code that can be
obtained by L<ERR_get_error(3)> if the allocation
fails. Otherwise it returns a pointer to the newly allocated structure.

=head1 SEE ALSO

L<DSA_new(3)>, L<DSA_new(3)>, L<DSA_meth_new(3)>

=head1 HISTORY

All of these functions were deprecated in OpenSSL 3.0.

=head1 COPYRIGHT

Copyright 2000-2025 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

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