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life_cycle-mac

NAME

life_cycle-mac - The MAC algorithm life-cycle

DESCRIPTION

All message authentication codes (MACs) go through a number of stages in their life-cycle:

  • start

    This state represents the MAC before it has been allocated. It is the starting state for any life-cycle transitions.

  • newed

    This state represents the MAC after it has been allocated.

  • initialised

    This state represents the MAC when it is set up and capable of processing input.

  • updated

    This state represents the MAC when it is set up and capable of processing additional input or generating output.

  • finaled

    This state represents the MAC when it has generated output.

  • freed

    This state is entered when the MAC is freed. It is the terminal state for all life-cycle transitions.

State Transition Diagram

The usual life-cycle of a MAC is illustrated:

Formal State Transitions

This section defines all of the legal state transitions. This is the canonical list.

Function CallCurrent State
startnewedinitialisedupdatedfinaledfreed
EVP_MAC_CTX_newnewed
EVP_MAC_initinitialisedinitialisedinitialisedinitialised
EVP_MAC_updateupdatedupdated
EVP_MAC_finalfinaled
EVP_MAC_finalXOFfinaled
EVP_MAC_CTX_freefreedfreedfreedfreedfreed
EVP_MAC_CTX_get_paramsnewedinitialisedupdated
EVP_MAC_CTX_set_paramsnewedinitialisedupdated
EVP_MAC_CTX_gettable_paramsnewedinitialisedupdated
EVP_MAC_CTX_settable_paramsnewedinitialisedupdated

NOTES

At some point the EVP layer will begin enforcing the transitions described herein.

SEE ALSO

provider-mac(7), EVP_MAC(3).

HISTORY

The provider MAC interface was introduced in OpenSSL 3.0.

Copyright 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.