EVP_MD-MD5-SHA1(7ossl)

📦
version 15.1 · 3 versions
, in freebsd 15.1

💅 EVP_MD-MD5-SHA1 — the MD5-SHA1 EVP_MD implementation 🎀

okay so bestie, this is a page from the OpenSSL manual set (you know, EVP_MD-MD5-SHA1(7ossl)) and it's about one very specific, very ✨ niche ✨ little digest. buckle up, it's short but it's iconic.

🌸 NAME 🌸

EVP_MD-MD5-SHA1 — literally just the MD5-SHA1 EVP_MD implementation. that's the whole name. periodt.

🦋 DESCRIPTION 🦋

so this is all about support for computing MD5-SHA1 digests through the EVP_MD API. that's the vibe. 🫶

and MD5-SHA1 is, like, a rather special digest — no cap — that's used with SSLv3. it's giving vintage. it's giving legacy-protocol main character energy. 💀

👑 Identity 👑

okay so this implementation? it's only available with the default provider, and it's identified with the name "MD5-SHA1". that's its whole government name, don't try to call it anything else. 💅

🎀 Gettable Parameters 🎀

this implementation supports the common gettable parameters described in EVP_MD-common(7). the standard ones! nothing extra to learn here, go read that page if you want the deets. ✨

🍓 Settable Context Parameters 🍓

okay now this is the juicy part — this implementation supports the following OSSL_PARAM(3) entries, settable for an EVP_MD_CTX with EVP_MD_CTX_set_params(3):

  • "ssl3-ms" (OSSL_DIGEST_PARAM_SSL3_MS) <octet string> — so this parameter gets set by libssl in order to calculate a signature hash for an SSLv3 CertificateVerify message as per RFC6101. and listen, it's only set after all handshake messages have already been digested via OP_digest_update() calls. the parameter provides the master secret value to be added to the digest, and the digest implementation should calculate the complete digest as per RFC6101 section 5.6.8. also — important — the next call after setting this parameter should be OP_digest_final(). so like, don't be weird about it, okay? 🙈
lowkey important: this lil param is part of a very specific SSLv3 flow, so don't just go setting it randomly and expecting cute results. respect the handshake order. 🔥

🌈 SEE ALSO 🌈

go read these next, iykyk 🧚

Copyright 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>.

okay that's the whole page bestie, you ate that 🫶💅 — this was OpenSSL 3.5.6, dated 2026-04-07, and that's the tea ⭐🌸

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