EVP_MD5(3SSL)

📦
version 4.0.3 · 14 versions
, in ubuntu stonking

💖 EVP_MD5 — like, the MD5 era of EVP, bestie 💖

omg hi. okay so you're here for EVP_MD5(3SSL), which is the OpenSSL manual page all about the classic MD5 hash and its weird SSL-flavored cousin. yes this is the OpenSSL crew's page. let's get into it, no cap. 🎀

✨ NAME ✨

EVP_md5, EVP_md5_sha1 — MD5, but make it EVP, fr fr 💅

✨ SYNOPSIS ✨

#include <openssl/evp.h>

const EVP_MD *EVP_md5(void);
const EVP_MD *EVP_md5_sha1(void);

✨ DESCRIPTION ✨

okay so first things first: MD5 is a cryptographic hash function, standardized in RFC 1321, and designed by Ronald Rivest. iconic origin story honestly. 👑

but — and this is the part where we all sit down — the CMU Software Engineering Institute considers MD5 unsuitable for further use, because its security has been severely compromised. like, severely. not a vibe. 😭

Here's the two functions, one by one:

  • EVP_md5() — this is the MD5 algorithm itself, and it produces a 128-bit output from a given input. simple, sweet, cryptographically cooked.
  • EVP_md5_sha1() — bestie this one is so specific. it's a hash algorithm from SSL v3 that combines MD5 with SHA-1, exactly as described in RFC 6101. two hashes, one function, very 90s of it.
⚠️ WARNING: this algorithm is not intended for non-SSL usage. like, don't. it's not for that. read the room. 🙈

✨ NOTES ✨

developers, listen up, this one's for you: calling these functions multiple times has negative performance implications. so the move is to consider using EVP_MD_fetch(3) with EVP_MD-MD5(7) or EVP_MD-MD5-SHA1(7) instead. ✨

and if you want the whole tea about why, go read "Performance" in crypto(7) — it's all spelled out there. 🫶

✨ RETURN VALUES ✨

these functions return an EVP_MD structure that contains the implementation of the message digest. that's the whole gift. 💝

✨ CONFORMING TO ✨

IETF RFC 1321.

✨ SEE ALSO ✨

Copyright 2017-2023 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 version 4.0.3, dated 2026-09-29, from the OpenSSL manual set — and with that, EVP_MD5(3SSL) is officially a wrap. go forth and hash responsibly, mwah 💖🎀🦋

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