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✏️ Editing: DSA_set_method.3

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.\" ========================================================================
.\"
.IX Title "DSA_SET_METHOD 3"
.TH DSA_SET_METHOD 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
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.nh
.SH "NAME"
DSA_set_default_method, DSA_get_default_method, DSA_set_method, DSA_new_method, DSA_OpenSSL \- select DSA method
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #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);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
A \fB\s-1DSA_METHOD\s0\fR specifies the functions that OpenSSL uses for \s-1DSA\s0
operations. By modifying the method, alternative implementations
such as hardware accelerators may be used. \s-1IMPORTANT:\s0 See the \s-1NOTES\s0 section for
important information about how these \s-1DSA API\s0 functions are affected by the use
of \fB\s-1ENGINE\s0\fR \s-1API\s0 calls.
.PP
Initially, the default \s-1DSA_METHOD\s0 is the OpenSSL internal implementation,
as returned by \fBDSA_OpenSSL()\fR.
.PP
\&\fBDSA_set_default_method()\fR makes \fBmeth\fR the default method for all \s-1DSA\s0
structures created later.
\&\fB\s-1NB\s0\fR: This is true only whilst no \s-1ENGINE\s0 has
been set as a default for \s-1DSA,\s0 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.
.PP
\&\fBDSA_get_default_method()\fR returns a pointer to the current default
\&\s-1DSA_METHOD.\s0 However, the meaningfulness of this result is dependent on
whether the \s-1ENGINE API\s0 is being used, so this function is no longer
recommended.
.PP
\&\fBDSA_set_method()\fR selects \fBmeth\fR to perform all operations using the key
\&\fBrsa\fR. This will replace the \s-1DSA_METHOD\s0 used by the \s-1DSA\s0 key and if the
previous method was supplied by an \s-1ENGINE,\s0 the handle to that \s-1ENGINE\s0 will
be released during the change. It is possible to have \s-1DSA\s0 keys that only
work with certain \s-1DSA_METHOD\s0 implementations (e.g. from an \s-1ENGINE\s0 module
that supports embedded hardware-protected keys), and in such cases
attempting to change the \s-1DSA_METHOD\s0 for the key can have unexpected
results. See DSA_meth_new for information on constructing custom \s-1DSA_METHOD\s0
objects;
.PP
\&\fBDSA_new_method()\fR allocates and initializes a \s-1DSA\s0 structure so that \fBengine\fR
will be used for the \s-1DSA\s0 operations. If \fBengine\fR is \s-1NULL,\s0 the default engine
for \s-1DSA\s0 operations is used, and if no default \s-1ENGINE\s0 is set, the \s-1DSA_METHOD\s0
controlled by \fBDSA_set_default_method()\fR is used.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBDSA_OpenSSL()\fR and \fBDSA_get_default_method()\fR return pointers to the respective
\&\fB\s-1DSA_METHOD\s0\fRs.
.PP
\&\fBDSA_set_default_method()\fR returns no value.
.PP
\&\fBDSA_set_method()\fR returns nonzero if the provided \fBmeth\fR was successfully set as
the method for \fBdsa\fR (including unloading the \s-1ENGINE\s0 handle if the previous
method was supplied by an \s-1ENGINE\s0).
.PP
\&\fBDSA_new_method()\fR returns \s-1NULL\s0 and sets an error code that can be
obtained by \fBERR_get_error\fR\|(3) if the allocation
fails. Otherwise it returns a pointer to the newly allocated structure.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBDSA_new\fR\|(3), \fBDSA_new\fR\|(3), \fBDSA_meth_new\fR\|(3)
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2000\-2020 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the OpenSSL license (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.

MR SKB