EVP_CIPHER-NULL(7ossl)

📦 version 3.5.0, in opensuse-leap 16.0

💖 EVP_CIPHER-NULL 💖

okay so this is the 7ossl page for EVP_CIPHER-NULL, and bestie, it's literally the most unserious cipher in the whole OpenSSL lineup — it's the cipher that does nothing and it's iconic for exactly that reason 💅

✨ NAME ✨

EVP_CIPHER-NULL — the NULL EVP_CIPHER implementation, no cap 🎀

🌸 SYNOPSIS 🌸

no separate synopsis section here, she's built right into the EVP_CIPHER API, so just go read the DESCRIPTION, i promise it's short and slay 🦋

✨ DESCRIPTION ✨

So there's support for a NULL symmetric encryption using the EVP_CIPHER API — yes, a cipher that does not cipher. It's used when the TLS cipher suite is TLS_NULL_WITH_NULL_NULL. It does no encryption at all (it literally just copies the data, like copy-paste energy) and it has a mac size of zero. Zero! Nothing! The void! 💀

🎀 Algorithm Name 🎀

The following algorithm is available in the default provider:

  • "NULL"

🦋 Parameters 🦋

This implementation supports the following parameters:

Gettable EVP_CIPHER parameters

See "Gettable EVP_CIPHER parameters" in EVP_EncryptInit(3)

Gettable EVP_CIPHER_CTX parameters

  • "keylen" (OSSL_CIPHER_PARAM_KEYLEN) <unsigned integer>
  • "ivlen" (OSSL_CIPHER_PARAM_IVLEN and <OSSL_CIPHER_PARAM_AEAD_IVLEN) <unsigned integer>
  • "tls-mac" (OSSL_CIPHER_PARAM_TLS_MAC) <octet ptr>

See "PARAMETERS" in EVP_EncryptInit(3) for further information.

Settable EVP_CIPHER_CTX parameters

  • "tls-mac-size" (OSSL_CIPHER_PARAM_TLS_MAC_SIZE) <unsigned integer>

See "PARAMETERS" in EVP_EncryptInit(3) for further information.

👑 CONFORMING TO 👑

RFC 5246 section-6.2.3.1 — yes she cites an RFC, she's got receipts 📜

🌈 SEE ALSO 🌈

Copyright 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>.

fr fr, that's the whole page — she's small but she's doing her job (which is nothing, but she's doing it flawlessly) 🫶

mwah, that's a wrap! this was version 3.5.0, dated 2026-09-25 — go off, bestie, and remember: sometimes the most powerful cipher is the one that does absolutely nothing ✨💖

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