.Dd $Mdocdate: November 2 2016 $
.Dt DSA_DUP_DH 3
.Os
.Sh NAME
.Nm DSA_dup_DH
.Nd create a DH structure out of DSA structure
.Sh SYNOPSIS
.In openssl/dsa.h
.Ft DH *
.Fo DSA_dup_DH
.Fa "const DSA *r"
.Fc
.Sh DESCRIPTION
.Fn DSA_dup_DH
duplicates
.Vt DSA
parameters/keys as
.Vt DH
parameters/keys.
.Fa r->q
is lost during that conversion, but the resulting
.Vt DH
parameters contain its length.
.Sh RETURN VALUE
.Fn DSA_dup_DH
returns the new
.Vt DH
structure or
.Dv NULL
on error.
The error codes can be obtained by
.Xr ERR_get_error 3 .
.Sh SEE ALSO
.Xr dh 3 ,
.Xr dsa 3 ,
.Xr ERR_get_error 3
.Sh HISTORY
.Fn DSA_dup_DH
was added in OpenSSL 0.9.4.
.Sh CAVEATS
Be careful to avoid small subgroup attacks when using this.