OSSL_PROVIDER-LEGACY(7ossl)

hey bestie 💖 this page is OSSL_PROVIDER-LEGACY(7ossl), the manual for the OpenSSL legacy provider — and it’s giving “retirement home for cryptographic algorithms” in the most iconic way. 🎀

💖 NAME 💖

OSSL_PROVIDER-legacy — OpenSSL legacy provider

✨ DESCRIPTION ✨

okay so the OpenSSL legacy provider supplies OpenSSL implementations of algorithms that have been deemed legacy. Such algorithms 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. periodt. 💅

💅 Properties

The implementations in this provider specifically has this property defined:

"provider=legacy"

It may be used 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). ✨

It isn’t mandatory to query for any of these properties, except to make sure to get implementations of this provider and none other. lowkey important, ngl.

🌈 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.
• 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 🦋

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.
• SEED, see EVP_CIPHER-SEED(7)

🍓 Key Derivation Function (KDF) 🍓

• PBKDF1
• PVKKDF

👑 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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and that’s the cute little footer, bestie: OpenSSL 3.5.0, dated 2026-09-25 — mwah 💋💖🦋