=pod =head1 NAME life_cycle-mac - The MAC algorithm life-cycle =head1 DESCRIPTION All message authentication codes (MACs) go through a number of stages in their life-cycle: =over 4 =item start This state represents the MAC before it has been allocated. It is the starting state for any life-cycle transitions. =item newed This state represents the MAC after it has been allocated. =item initialised This state represents the MAC when it is set up and capable of processing input. =item updated This state represents the MAC when it is set up and capable of processing additional input or generating output. =item finaled This state represents the MAC when it has generated output. =item freed This state is entered when the MAC is freed. It is the terminal state for all life-cycle transitions. =back =head2 State Transition Diagram The usual life-cycle of a MAC is illustrated: =begin man +-------------------+ | 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 | +-------------------+ =end man =for html =head2 Formal State Transitions This section defines all of the legal state transitions. This is the canonical list. =begin man 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 =end man =begin html

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 |  |

=end html =head1 NOTES At some point the EVP layer will begin enforcing the transitions described herein. =head1 SEE ALSO L, L. =head1 HISTORY The provider MAC interface was introduced in OpenSSL 3.0. =head1 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 L. =cut