LIFE_CYCLE-MAC(7SSL) OpenSSL LIFE_CYCLE-MAC(7SSL)
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.
SEE ALSO
provider-mac(7), EVP_MAC(3).
HISTORY
The provider MAC interface was introduced in OpenSSL 3.0.
COPYRIGHT
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>.
3.5.4 2025-09-30 LIFE_CYCLE-MAC(7SSL)
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