OSSL_PROVIDER-LEGACY(7ossl)

💖 NAME 💖

OSSL_PROVIDER-LEGACY(7ossl) — bestie, this is the page for OSSL_PROVIDER-legacy, aka the OpenSSL legacy provider. 🫶 It's the provider that keeps the old-school cryptographic algorithms around, and this manual tells you all about it. ✨

✨ DESCRIPTION ✨

Okay so listen: the OpenSSL legacy provider supplies OpenSSL implementations of algorithms that have been deemed legacy. These are algorithms that have commonly fallen out of use, have been deemed insecure by the cryptography community, or something similar. 😭

We can consider this the retirement home of cryptographic algorithms. No cap. 🏡💅

🎀 Properties 🎀

The implementations in this provider specifically have this property defined, periodt:

"provider=legacy"

You can use it in a property query string with fetching functions such as EVP_MD_fetch(3) or EVP_CIPHER_fetch(3), and also with other functions that take a property query string, like EVP_PKEY_CTX_new_from_name(3). 💖

It isn't mandatory to query for any of these properties — except to make sure you get implementations from this provider and none other. 🎯

🔥 OPERATIONS AND ALGORITHMS 🔥

The OpenSSL legacy provider supports these operations and algorithms:

🍓 Hashing Algorithms / Message Digests 🍓

• MD2, see EVP_MD-MD2(7) — disabled by default. Use the enable-md2 config option to enable it. 🙈
• MD4, see EVP_MD-MD4(7) — yes bestie, it's in here. 💅
• MDC2, see EVP_MD-MDC2(7) — iconic legacy behavior. 🎀
• WHIRLPOOL, see EVP_MD-WHIRLPOOL(7) — she's got main character energy. 🌊
• RIPEMD160, see EVP_MD-RIPEMD160(7) — still holding it down. 💜

🌸 Symmetric Ciphers 🌸

Not all of these symmetric cipher algorithms are enabled by default. 💀

• Blowfish, see EVP_CIPHER-BLOWFISH(7) — 🐡
• CAST, see EVP_CIPHER-CAST(7) — 🎬
• DES, see EVP_CIPHER-DES(7) — the algorithm names are DES_ECB, DES_CBC, DES_OFB, DES_CFB, DES_CFB1, DES_CFB8 and DESX_CBC. 👑
• IDEA, see EVP_CIPHER-IDEA(7) — a whole vibe. 💡
• RC2, see EVP_CIPHER-RC2(7) — 🧚
• RC4, see EVP_CIPHER-RC4(7) — 😭
• RC5, see EVP_CIPHER-RC5(7) — disabled by default. Use the enable-rc5 config option to enable it. 🔥
• SEED, see EVP_CIPHER-SEED(7) — 🌱

🦋 Key Derivation Function (KDF) 🦋

• PBKDF1 — yes, that one. 💫
• PVKKDF — also chillin' right here. 🫶

🌈 SEE ALSO 🌈

• OSSL_PARAM(3)
• openssl-core.h(7)
• openssl-core_dispatch.h(7)
• provider(7)

⭐ HISTORY ⭐

This functionality was added in OpenSSL 3.0. 🎉

💜 COPYRIGHT 💜

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>.

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okay bye bestie — this page is from OpenSSL 3.5.9, dated 2026-09-29! 💖✨