DSA_DUP_DH(3ossl)

📦
version 3.5.9 · 8 versions
, in fedora 43, fedora 44

💖 DSA_DUP_DH 💖

okay bestie, gather round, we're reading the DSA_dup_DH page from the OpenSSL manual (that's manual section 3ossl, iykyk) and it's... a lot. it's giving deprecated. let's get into it 🫶

✨ NAME ✨

DSA_dup_DH — bestie, it makes a DH structure out of a DSA structure. that's the whole job. one (1) job. 💅

🌈 SYNOPSIS 🌈

#include <openssl/dsa.h>

so here's the tea, and the tea is deprecated 🫠 — these functions have been deprecated since OpenSSL 3.0, and you can hide them entirely by defining OPENSSL_API_COMPAT with a suitable version value. peep openssl_user_macros(7) for the deets on that.

DH *DSA_dup_DH(const DSA *r);

that's it. that's the function. one signature, no cap. ✨

🦋 DESCRIPTION 🦋

first things first: the function on this page is deprecated, periodt. there's no direct replacement — instead, applications should use the EVP_PKEY APIs for Diffie-Hellman operations. that's the glow-up, bestie. go there. 🧚

so what does DSA_dup_DH() actually do? it duplicates DSA parameters/keys as DH parameters/keys. iconic of it. q is lost during that conversion 😭 — like, gone gone — but the resulting DH parameters do contain its length. so not a total loss, just a little ghost of q living rent-free in there. 🎀

💜 RETURN VALUES 💜

DSA_dup_DH() returns the new DH structure, and NULL on error. when it goes wrong (and it might 🫣) you can grab the error codes with ERR_get_error(3). always check your returns, bestie, fr fr.

🎀 NOTE 🎀

⚠️ be careful to avoid small subgroup attacks when using this. that's not a vibe, that's a real warning. protect yourself. 💀

🌸 SEE ALSO 🌸

⭐ HISTORY ⭐

this function was deprecated in OpenSSL 3.0. it had a good run, honestly. 👑

Copyright 2000-2020 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 <https://www.openssl.org/source/license.html>.

and that's the whole page, bestie!! 🎉 written up for OpenSSL 3.5.9, dated 2026-09-29 — catch you in the next manpage, mwah 💅💖✨

📦 where this page comes from