NAME

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

SYNOPSIS

        #include <openssl/dsa.h>

        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);

        DSA_METHOD *DSA_OpenSSL(void);

DESCRIPTION

       A DSA_METHOD specifies the functions that OpenSSL uses for DSA operations. By modifying
       the method, alternative implementations such as hardware accelerators may be used.
       IMPORTANT: See the NOTES section for important information about how these DSA API
       functions are affected by the use of ENGINE API calls.

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

       DSA_set_default_method() makes meth the default method for all DSA structures created
       later.  NB: This is true only whilst no ENGINE has been set as a default for DSA, so this
       function is no longer recommended.  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. However, the
       meaningfulness of this result is dependent on whether the ENGINE API is being used, so
       this function is no longer recommended.

       DSA_set_method() selects meth to perform all operations using the key rsa. This will
       replace the DSA_METHOD used by the DSA key and if the previous method was supplied by an
       ENGINE, the handle to that ENGINE will be released during the change. It is possible to
       have DSA keys that only work with certain DSA_METHOD implementations (eg. from an ENGINE
       module that supports embedded hardware-protected keys), and in such cases attempting to
       change the DSA_METHOD for the key can have unexpected results. See DSA_meth_new for
       information on constructing custom DSA_METHOD objects;

       DSA_new_method() allocates and initializes a DSA structure so that engine will be used for
       the DSA operations. If engine is NULL, the default engine for DSA operations is used, and
       if no default ENGINE is set, the DSA_METHOD controlled by DSA_set_default_method() is
       used.

RETURN VALUES

       DSA_OpenSSL() and DSA_get_default_method() return pointers to the respective DSA_METHODs.

       DSA_set_default_method() returns no value.

       DSA_set_method() returns non-zero if the provided meth was successfully set as the method
       for dsa (including unloading the ENGINE handle if the previous method was supplied by an
       ENGINE).

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

SEE ALSO

       DSA_new(3), DSA_new(3), DSA_meth_new(3)

COPYRIGHT

       Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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 <https://www.openssl.org/source/license.html>.