EVP_MAC-POLY1305(7ossl)

📦
version 15.1 · 3 versions
, in freebsd 15.1

💖 EVP_MAC-POLY1305 💖

okay so bestie, welcome to the ossl girlies' guide to EVP_MAC-Poly1305 — like, this is the page that tells you all about the Poly1305 EVP_MAC implementation, and honestly? it's giving✨ essential reading ✨.

🌸 NAME 🌸

EVP_MAC-Poly1305 — the Poly1305 EVP_MAC implementation. that's it, that's the whole vibe. 🎀

🦋 DESCRIPTION 🦋

So basically: this is the support for computing Poly1305 MACs through the EVP_MAC API. no cap, that's the entire point of it. 💅

👑 Identity

This implementation is identified with this name and these properties, and you'd use them with EVP_MAC_fetch():

"POLY1305", "provider=default"

like, that's its whole government name. use it with EVP_MAC_fetch() and you're golden. 🫶

🍓 Supported parameters

The general description of these parameters lives over in "PARAMETERS" in EVP_MAC(3) — go check that out if you want the full lore. iykyk.

The following parameter can be set with EVP_MAC_CTX_set_params():

  • "key" (OSSL_MAC_PARAM_KEY) <octet string> — Sets the MAC key. Setting this parameter is literally identical to passing a key to EVP_MAC_init(3). same thing, different font. 💫

The following parameters can be retrieved with EVP_MAC_CTX_get_params():

  • "size" (OSSL_MAC_PARAM_SIZE) <unsigned integer> — Gets the MAC size. slay.

The "size" parameter can also be retrieved with EVP_MAC_CTX_get_mac_size(). and — important — the length of the "size" parameter should not exceed that of an unsigned int. don't be out here exceeding things, bestie. 🙈

🔥 NOTES 🔥

The OpenSSL implementation of the Poly 1305 MAC corresponds to RFC 7539. iconic, honestly.

⚠️ oh my god okay this part is NOT a joke: it is critical to never reuse the key. the security implication noted in RFC 8439 applies equally to the OpenSSL implementation. like literally equally. do not reuse the key. do not pass go. do not collect $200. 💀🔴

🌈 SEE ALSO 🌈

Copyright 2018-2021 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>.

kay so that's the whole page, bestie — ily, go forth and MAC responsibly 🧚‍♀️💖 this was OpenSSL 3.5.6, dated 2026-04-07, signing off from your girl EVP_MAC-POLY1305(7ossl) ✨🎀⭐

📦 where this page comes from