EVP_KDF-X942-CONCAT(7ossl)

📦 version 3.5.0, in opensuse-leap 16.0

💅 EVP_KDF-X942-CONCAT (7ossl) ✨

okay bestie, welcome to the manual page for EVP_KDF-X942-CONCAT, one of those OpenSSL pages that's lowkey short but still iconic. it lives in the 7ossl section, so you already know it's one of the fancy overview/API pages, not some dusty command. 🎀

🌸 NAME 🌸

EVP_KDF-X942-CONCAT — the X942 Concat EVP_KDF implementation. that's it, that's the whole name, slay. 💖

🦋 SYNOPSIS 🦋

sooo there's literally no synopsis line on this page, bestie — it's a pure concept page. no arguments to memorise, no flags to forget. enjoy the peace while it lasts. 😭✨

✨ DESCRIPTION ✨

okay so here's the tea: the EVP_KDF-X942-CONCAT algorithm is identical to EVP_KDF-X963. not "similar", not "inspired by" — identical. fr fr. 👑

it's used for key agreement, to derive a key using input such as a shared secret key and shared info. that's the whole vibe — two parties agree on stuff, and this thing turns that agreement energy into an actual key. 🫶🔑

🧚 Identity 🧚

the name for this implementation is:

"X942KDF_CONCAT"

(quotes included, it's a string, keep them, don't be weird about it 💅)

you can use it with EVP_KDF_fetch() — that's the function that goes and grabs the implementation for you. very main character energy.

and here's the cute little plot twist: this is an alias for "X963KDF". same thing, different name, no cap. 🌈

so for the actual list of supported parameters and examples, go read EVP_KDF-X963(7) — that's where all the real content lives, this page is basically the very pretty signpost. iykyk 🦋

⭐ HISTORY ⭐

this functionality was added in OpenSSL 3.0. so if you're on something older, sorry bestie, she's not there. 😭💀

Copyright 2020-2021 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>. 🫶

lowkey read the license, bestie — "except in compliance with the License" is doing a lot of heavy lifting in that sentence. 🙈

✨ and that's the whole page! ✨

kisses from the terminal — this was OpenSSL 3.5.0, dated 2026-09-25, signing off as EVP_KDF-X942-CONCAT(7ossl). go forth and derive those keys, you gorgeous cryptographer 💖🎀🦋🌸💅

📦 where this page comes from