LIFE_CYCLE-MAC

Section: OpenSSL (7SSL)
Updated: 2024-03-03
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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:
                 +-------------------+
                 |       start       |
                 +-------------------+
                   |
                   | EVP_MAC_CTX_new
                   v
                 +-------------------+
                 |       newed       |
                 +-------------------+
                   |
                   | EVP_MAC_init
                   v
                 +-------------------+
              +> |    initialised    | <+
              |  +-------------------+  |
              |    |                    |
              |    | EVP_MAC_update     | EVP_MAC_init
              |    v                    |
EVP_MAC_init |  +-------------------+  |
              |  |      updated      | -+
              |  +-------------------+
              |    |               |
              |    | EVP_MAC_final | EVP_MAC_finalXOF
              |    v               v
              |  +-------------------+
              +- |      finaled      |
                 +-------------------+
                   |
                   | EVP_MAC_CTX_free
                   v
                 +-------------------+
                 |       freed       |
                 +-------------------+

Formal State Transitions

This section defines all of the legal state transitions. This is the canonical list.
Function Call                   --------------------- Current State ----------------------
                                 start   newed    initialised   updated     finaled   freed
EVP_MAC_CTX_new                 newed
EVP_MAC_init                         initialised initialised initialised initialised
EVP_MAC_update                                     updated     updated
EVP_MAC_final                                                  finaled
EVP_MAC_finalXOF                                               finaled
EVP_MAC_CTX_free                freed   freed       freed       freed       freed
EVP_MAC_CTX_get_params                  newed    initialised   updated
EVP_MAC_CTX_set_params                  newed    initialised   updated
EVP_MAC_CTX_gettable_params             newed    initialised   updated
EVP_MAC_CTX_settable_params             newed    initialised   updated

NOTES

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

HISTORY

The provider MAC interface was introduced in OpenSSL 3.0.

COPYRIGHT

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>.

Index

NAME

DESCRIPTION

State Transition Diagram
Formal State Transitions

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Time: 21:28:08 GMT, May 07, 2024