LIFE_CYCLE-DIGEST
Section: OpenSSL (7SSL)
Updated: 2024-03-03
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NAME
life_cycle-digest - The digest algorithm life-cycle
DESCRIPTION
All message digests (MDs) go through a number of stages in their life-cycle:
- start
-
This state represents the MD before it has been allocated. It is the
starting state for any life-cycle transitions.
- newed
-
This state represents the MD after it has been allocated.
- initialised
-
This state represents the MD when it is set up and capable of processing
input.
- updated
-
This state represents the MD when it is set up and capable of processing
additional input or generating output.
- finaled
-
This state represents the MD when it has generated output.
- freed
-
This state is entered when the MD is freed. It is the terminal state
for all life-cycle transitions.
State Transition Diagram
The usual life-cycle of a MD is illustrated:
+-------------------+
| start |
+-------------------+
|
| EVP_MD_CTX_new
v
+-------------------+ EVP_MD_CTX_reset
| newed | <------------------------------+
+-------------------+ |
| |
| EVP_DigestInit |
v |
+-------------------+ |
+--> | initialised | <+ EVP_DigestInit |
| +-------------------+ | |
| | | EVP_DigestUpdate |
| | EVP_DigestUpdate | +------------------+ |
| v | v | |
| +------------------------------------------------+ |
EVP_DigestInit | | updated | --+
| +------------------------------------------------+ |
| | | |
| | EVP_DigestFinal | EVP_DigestFinalXOF |
| v v |
| +------------------------------------------------+ |
+--- | finaled | --+
+------------------------------------------------+
|
| EVP_MD_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_MD_CTX_new newed
EVP_DigestInit initialised initialised initialised initialised
EVP_DigestUpdate updated updated
EVP_DigestFinal finaled
EVP_DigestFinalXOF finaled
EVP_MD_CTX_free freed freed freed freed freed
EVP_MD_CTX_reset newed newed newed newed
EVP_MD_CTX_get_params newed initialised updated
EVP_MD_CTX_set_params newed initialised updated
EVP_MD_CTX_gettable_params newed initialised updated
EVP_MD_CTX_settable_params newed initialised updated
NOTES
At some point the EVP layer will begin enforcing the transitions described
herein.
SEE ALSO
provider-digest(7), EVP_DigestInit(3)
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>.
Index
- NAME
-
- DESCRIPTION
-
- State Transition Diagram
-
- Formal State Transitions
-
- NOTES
-
- SEE ALSO
-
- COPYRIGHT
-
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Time: 05:46:29 GMT, April 28, 2024