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.IX Title "DSA_DUP_DH 3ossl"
.TH DSA_DUP_DH 3ossl 2026-01-27 3.5.5 OpenSSL
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.SH NAME
DSA_dup_DH \- create a DH structure out of DSA structure
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/dsa.h>
.Ve
.PP
The following functions have been deprecated since OpenSSL 3.0, and can be
hidden entirely by defining \fBOPENSSL_API_COMPAT\fR with a suitable version value,
see \fBopenssl_user_macros\fR\|(7):
.PP
.Vb 1
\& DH *DSA_dup_DH(const DSA *r);
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
The function described on this page is deprecated. There is no direct
replacement, applications should use the EVP_PKEY APIs for Diffie\-Hellman
operations.
.PP
\&\fBDSA_dup_DH()\fR duplicates DSA parameters/keys as DH parameters/keys. q
is lost during that conversion, but the resulting DH parameters
contain its length.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBDSA_dup_DH()\fR returns the new \fBDH\fR structure, and NULL on error. The
error codes can be obtained by \fBERR_get_error\fR\|(3).
.SH NOTE
.IX Header "NOTE"
Be careful to avoid small subgroup attacks when using this.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBDH_new\fR\|(3), \fBDSA_new\fR\|(3), \fBERR_get_error\fR\|(3)
.SH HISTORY
.IX Header "HISTORY"
This function was deprecated in OpenSSL 3.0.
.SH COPYRIGHT
.IX Header "COPYRIGHT"
Copyright 2000\-2020 The OpenSSL Project Authors. All Rights Reserved.
.PP
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
<https://www.openssl.org/source/license.html>.
