.. index:: single: cmac_protocol
.. _cmac_protocol/0:

.. rst-class:: right

**protocol**

``cmac_protocol``
=================

Protocol for one-shot CMAC digest computation using block cipher objects implementing ``block_cipher_prepared_key_protocol``.

| **Availability:** 
|    ``logtalk_load(cmac(loader))``

| **Author:** Paulo Moura
| **Version:** 1:0:0
| **Date:** 2026-08-08

| **Compilation flags:**
|    ``static``


| **Dependencies:**
|   (none)


| **Remarks:**
|    (none)

| **Inherited public predicates:**
|    (none)

.. contents::
   :local:
   :backlinks: top

Public predicates
-----------------

.. index:: digest/4
.. _cmac_protocol/0::digest/4:

``digest/4``
^^^^^^^^^^^^

Computes the full CMAC digest for a block cipher object, key bytes, and message bytes.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``digest(Cipher,KeyBytes,MessageBytes,DigestBytes)``
| **Mode and number of proofs:**
|    ``digest(+object_identifier,+list(byte),+list(byte),--list(byte))`` - ``one_or_error``

| **Exceptions:**
|    ``Cipher`` or ``MessageBytes`` is a variable or a partial list:
|        ``instantiation_error``
|    ``Cipher`` does not implement the required prepared-key block cipher protocol:
|        ``domain_error(cmac_cipher,Cipher)``
|    ``Cipher`` reports a block size other than 8 or 16 bytes:
|        ``domain_error(cmac_block_size,BlockSize)``
|    ``MessageBytes`` is neither a variable nor a list:
|        ``type_error(list(byte),MessageBytes)``
|    ``MessageBytes`` contains a non-integer byte:
|        ``type_error(integer,Byte)``
|    ``MessageBytes`` contains an integer outside the byte range:
|        ``domain_error(byte,Byte)``


------------

.. index:: hex_digest/4
.. _cmac_protocol/0::hex_digest/4:

``hex_digest/4``
^^^^^^^^^^^^^^^^

Computes the full CMAC digest for a block cipher object, key bytes, and message bytes, returning a lowercase hexadecimal atom.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``hex_digest(Cipher,KeyBytes,MessageBytes,HexDigest)``
| **Mode and number of proofs:**
|    ``hex_digest(+object_identifier,+list(byte),+list(byte),--atom)`` - ``one_or_error``

| **Exceptions:**
|    ``Cipher`` or ``MessageBytes`` is a variable or a partial list:
|        ``instantiation_error``
|    ``Cipher`` does not implement the required prepared-key block cipher protocol:
|        ``domain_error(cmac_cipher,Cipher)``
|    ``Cipher`` reports a block size other than 8 or 16 bytes:
|        ``domain_error(cmac_block_size,BlockSize)``
|    ``MessageBytes`` is neither a variable nor a list:
|        ``type_error(list(byte),MessageBytes)``
|    An element ``Byte`` of the `MessageBytes`` list is neither a variable nor an integer:
|        ``type_error(integer,Byte)``
|    An element ``Byte`` of the ``MessageBytes`` list is an integer but not a valid byte:
|        ``domain_error(byte,Byte)``


------------

.. index:: digest/5
.. _cmac_protocol/0::digest/5:

``digest/5``
^^^^^^^^^^^^

Computes a truncated CMAC digest containing the requested number of leftmost bytes.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``digest(Cipher,KeyBytes,MessageBytes,Length,DigestBytes)``
| **Mode and number of proofs:**
|    ``digest(+object_identifier,+list(byte),+list(byte),+integer,--list(byte))`` - ``one_or_error``

| **Exceptions:**
|    ``Length`` is a variable:
|        ``instantiation_error``
|    ``Length`` is neither a variable nor an integer:
|        ``type_error(integer,Length)``
|    ``Length`` is an integer outside the range from one through the cipher block size:
|        ``domain_error(cmac_output_length(1,BlockSize),Length)``


------------

.. index:: hex_digest/5
.. _cmac_protocol/0::hex_digest/5:

``hex_digest/5``
^^^^^^^^^^^^^^^^

Computes a truncated CMAC digest containing the requested number of leftmost bytes and returns it as a lowercase hexadecimal atom.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``hex_digest(Cipher,KeyBytes,MessageBytes,Length,HexDigest)``
| **Mode and number of proofs:**
|    ``hex_digest(+object_identifier,+list(byte),+list(byte),+integer,--atom)`` - ``one_or_error``

| **Exceptions:**
|    ``Cipher``, ``MessageBytes``, or ``Length`` is a variable or a partial list:
|        ``instantiation_error``
|    ``Cipher`` does not implement the required prepared-key block cipher protocol:
|        ``domain_error(cmac_cipher,Cipher)``
|    ``Cipher`` reports a block size other than 8 or 16 bytes:
|        ``domain_error(cmac_block_size,BlockSize)``
|    ``MessageBytes`` is neither a variable nor a list:
|        ``type_error(list(byte),MessageBytes)``
|    An element ``Byte`` of the `MessageBytes`` list is neither a variable nor an integer:
|        ``type_error(integer,Byte)``
|    An element ``Byte`` of the ``MessageBytes`` list is an integer but not a valid byte:
|        ``domain_error(byte,Byte)``
|    ``Length`` is neither a variable nor an integer:
|        ``type_error(integer,Length)``
|    ``Length`` is an integer outside the range from one through the cipher block size:
|        ``domain_error(cmac_output_length(1,BlockSize),Length)``


------------

Protected predicates
--------------------

(none)

Private predicates
------------------

(none)

Operators
---------

(none)

.. seealso::

   :ref:`block_cipher_prepared_key_protocol <block_cipher_prepared_key_protocol/0>`