OSSL_PROVIDER-legacy(7ssl)

OSSL_PROVIDER-legacy7ssl

Openssl legacy provider

Overview

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.

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.

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

Releases

3 releases since Debian 12 (Bookworm); the text changed 2 times.

  1. 12
  2. 13
  3. Arch

History

This functionality was added in OpenSSL 3.0.

From openssl 3.6.5-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.