OSSL_PROVIDER-LEGACY(7ossl)

💜 OSSL_PROVIDER-LEGACY(7ossl) — the OpenSSL legacy provider, explained

okay so bestie, this is the 7ossl manual page for OSSL_PROVIDER-legacy, and honestly? it's giving retirement home for ciphers. let's get into it 🫶

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✨ NAME ✨

OSSL_PROVIDER-legacy — the OpenSSL legacy provider, aka where the old-school algorithms go to live out their golden years.

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🦋 DESCRIPTION 🦋

so the OpenSSL legacy provider supplies OpenSSL implementations of algorithms that have been deemed legacy. and like, what does "legacy" mean here? basically one of three vibes:

• they've commonly fallen out of use,
• the cryptography community has deemed them insecure,
• or "something similar" (their words, not mine 💀).

we can consider this the retirement home of cryptographic algorithms. no cap. they're comfy, they're chilling, they're not getting invited to the new projects. but they still live here and we love them 💅

🌸 Properties 🌸

the implementations in this provider specifically have this property defined:

"provider=legacy"

you may use it in a property query string with fetching functions such as EVP_MD_fetch(3) or EVP_CIPHER_fetch(3), as well as with other functions that take a property query string, such as EVP_PKEY_CTX_new_from_name(3). iykyk 🔥

and no, it isn't mandatory to query for any of these properties — except to make sure you get implementations of this provider and none other. so like, if you want to be certain bestie, say the property out loud. periodt.

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👑 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 enable-md2 config option to enable. (sorry bestie, you gotta opt in 🙈)
• MD4, see EVP_MD-MD4(7)
• MDC2, see EVP_MD-MDC2(7)
• WHIRLPOOL, see EVP_MD-WHIRLPOOL(7)
• RIPEMD160, see EVP_MD-RIPEMD160(7)

🌈 Symmetric Ciphers 🌈

heads up: 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)
• RC2, see EVP_CIPHER-RC2(7)
• RC4, see EVP_CIPHER-RC4(7)
• RC5, see EVP_CIPHER-RC5(7)
  • Disabled by default. Use enable-rc5 config option to enable. (again, opt in or it's not happening 🫶)
• SEED, see EVP_CIPHER-SEED(7)

🧚 Key Derivation Function (KDF) 🧚

• PBKDF1
• PVKKDF

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⭐ SEE ALSO ⭐

go read these next, bestie, they're iconic:

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

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💖 HISTORY 💖

this functionality was added in OpenSSL 3.0. so it's a 3.0 baby 🎀

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🌸 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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💀 real talk though: these algorithms are here because they're legacy — commonly unused, deemed insecure by the crypto community, or "something similar". don't go picking MD2 for your new project and calling it a slay. use them knowingly, okay? 🫶

and that's the page!! this was version 3.5.6, dated 2026-04-07, filed under OSSL_PROVIDER-LEGACY(7ossl) — mwah, go touch some modern crypto 💅✨🍓