EVP_MAC-CMAC(7SSL)

📦
version 4.0.3 · 13 versions
, in ubuntu stonking

💖 EVP_MAC-CMAC 💖

okay so bestie, welcome to EVP_MAC-CMAC(7SSL) — the OpenSSL glow-up of a manpage that's literally all about the CMAC EVP_MAC implementation. she's giving crypto main character energy and honestly? we stan. 💅

✨ NAME ✨

EVP_MAC-CMAC — the CMAC EVP_MAC implementation, periodt.

🦋 DESCRIPTION 🦋

it's support for computing CMAC MACs through the EVP_MAC API. that's the vibe.

this implementation uses EVP_CIPHER functions to get access to the underlying cipher. no cap. 🎀

👑 Identity

this implementation is identified with this name and these properties, to be used with EVP_MAC_fetch():

"CMAC", "provider=default" or "provider=fips"

🌸 Supported parameters

the general description of these parameters can be found in "PARAMETERS" in EVP_MAC(3). go read that if you want the full lore, iykyk.

the following parameter can be set with EVP_MAC_CTX_set_params():

  • "key" (OSSL_MAC_PARAM_KEY) <octet string> — sets the MAC key. setting this parameter is identical to passing a key to EVP_MAC_init(3). literally the same thing, bestie. 🔑
  • "cipher" (OSSL_MAC_PARAM_CIPHER) <UTF8 string> — sets the name of the underlying cipher to be used. the mode of the cipher must be CBC. not optional, not negotiable, she said CBC and she meant it. ⭐
  • "properties" (OSSL_MAC_PARAM_PROPERTIES) <UTF8 string> — sets the properties to be queried when trying to fetch the underlying cipher. this must be given together with the cipher naming parameter to be considered valid. they're a package deal, a duo, a situationship that actually works. 🫶
  • "encrypt-check" (OSSL_CIPHER_PARAM_FIPS_ENCRYPT_CHECK) <integer> — this option is used by the OpenSSL FIPS provider. if required, this parameter should be set before EVP_MAC_init().

the default value of 1 causes an error when an unapproved Triple-DES encryption operation is triggered. setting this to 0 will ignore the error and set the approved "fips-indicator" to 0.

⚠️ heads up bestie: this option breaks FIPS compliance if it causes the approved "fips-indicator" to return 0. like, actually breaks it. not a vibe check she passes. 💀

the following parameters can be retrieved with EVP_MAC_CTX_get_params():

  • "size" (OSSL_MAC_PARAM_SIZE) <unsigned integer> — the "size" parameter can also be retrieved with with EVP_MAC_CTX_get_mac_size(). the length of the "size" parameter is equal to that of an unsigned int. 📏
  • "block-size" (OSSL_MAC_PARAM_BLOCK_SIZE) <unsigned integer> — gets the MAC block size. the "block-size" parameter can also be retrieved with EVP_MAC_CTX_get_block_size(). 🧚
  • "fips-indicator" (OSSL_MAC_PARAM_FIPS_APPROVED_INDICATOR) <integer> — this option is used by the OpenSSL FIPS provider.

a getter that returns 1 if the operation is FIPS approved, or 0 otherwise. this may be used after calling EVP_MAC_final(). it may return 0 if the "encrypt-check" option is set to 0. 🔥

🌈 SEE ALSO 🌈

Copyright 2018-2026 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>.

and that's the whole page, bestie!! 🎀✨ this was version 4.0.3, dated 2026-09-29, and that's EVP_MAC-CMAC(7SSL) signing off — stay FIPS-approved, drink water, and go read the LICENSE file fr fr 💖🦋🌸

📦 where this page comes from