EVP_KEYEXCH-X25519(7ossl)

📦 version 3.5.0, in opensuse-leap 16.0

💖 EVP_KEYEXCH-X25519(7ossl) — X25519 & X448 Key Exchange, bestie edition ✨

okay so real talk, this is the OpenSSL manual page for the X25519 and X448 key exchange support. It lives in section 7ossl of the manual, and it's short and sweet — like, shockingly short, which honestly? iconic of it. Let's get into it 🎀

🌸 NAME 🌸

EVP_KEYEXCH-X25519, EVP_KEYEXCH-X448 — the X25519 and X448 Key Exchange algorithm support. that's the whole vibe, that's what we're doing here 💅

🦋 SYNOPSIS 🦋

no cap, there's no synopsis block on this one — it's giving "just read the description, babe." moving on 🫶

✨ DESCRIPTION ✨

So this page is all about key exchange support for the X25519 and X448 key types. That's the entire description, bestie. Short king energy 👑

🔥 Key exchange parameters 🔥

These are the params you can poke at, and here's the tea on each one:

  • "pad" (OSSL_EXCHANGE_PARAM_PAD) <unsigned integer> — that's the param name, that's the type, go off 💜 (the page literally gives you the name and the <unsigned integer> type and dips, so that's all we're working with here 🙈)
  • "fips-indicator" (OSSL_EXCHANGE_PARAM_FIPS_APPROVED_INDICATOR) <integer> — okay so this is the FIPS approval getter, and here's the important bit: X25519 and X448 are not FIPS approved in FIPS 140-3. So this getter will return 0. Periodt. No notes. 💀

and if you want the full scoop on the general ones, check out the "Common Key Exchange parameters" section over in provider-keyexch(7) 📖

🌈 EXAMPLES 🌈

okay so first things first: the keys for the host and the peer? you generate those exactly like it shows in the "Examples" section over in EVP_PKEY-X25519(7). cute, easy, slay ✨

and then the code to generate a shared secret? literally identical to the "Examples" section in EVP_KEYEXCH-DH(7). so if you've already read that one, you're basically done here. bestie, you ate 🍓

👀 SEE ALSO 👀

go touch some of these while you're at it, they're all friends:

(and yes, the original page has a stray comma hanging out at the end of that list and we're keeping it, it's part of the family now 💜)

Copyright 2020-2024 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>.

fr fr, read the license before you go copying stuff — that's not me being dramatic, that's the actual license text being the actual license text 💅

🎀 and that's the whole page! 🎀

This one's from OpenSSL 3.5.0, dated 2026-09-25, and it's the EVP_KEYEXCH-X25519(7ossl) page. short, sweet, FIPS-unapproved, and absolutely slaying. mwah 💋💖

📦 where this page comes from