man > life_cycle-pkey(7ssl)

LIFE_CYCLE-PKEY(7SSL)                          OpenSSL                         LIFE_CYCLE-PKEY(7SSL)

NAME
       life_cycle-pkey - The PKEY algorithm life-cycle

DESCRIPTION
       All public keys (PKEYs) go through a number of stages in their life-cycle:

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

       newed
           This state represents the PKEY after it has been allocated.

       decapsulate
           This state represents the PKEY when it is ready to perform a  private  key  decapsulation
           operation.

       decrypt
           This state represents the PKEY when it is ready to decrypt some ciphertext.

       derive
           This state represents the PKEY when it is ready to derive a shared secret.

       digest sign
           This  state  represents  the  PKEY  when  it  is ready to perform a private key signature
           operation.

       encapsulate
           This state represents the PKEY when it is ready to perform  a  public  key  encapsulation
           operation.

       encrypt
           This state represents the PKEY when it is ready to encrypt some plaintext.

       key generation
           This state represents the PKEY when it is ready to generate a new public/private key.

       parameter generation
           This state represents the PKEY when it is ready to generate key parameters.

       verify
           This state represents the PKEY when it is ready to verify a public key signature.

       verify recover
           This state represents the PKEY when it is ready to recover a public key signature data.

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

   State Transition Diagram
       The usual life-cycle of a PKEY object is illustrated:
                                                          +-------------+
                                                          |             |
                                                          |    start    |
                                                          |             |
                          EVP_PKEY_derive                 +-------------+
        +-------------+                    EVP_PKEY_derive_set_peer                                |
       +-------------+
        |                              |----------------------------+                              |
       +----------------------------|             |
        |   derive    |                            |              |              |   EVP_PKEY_verify
       |   verify    |
        |                              |<---------------------------+                              |
       +--------------------------->|             |
        +-------------+                                                                            |
       +-------------+
                    ^                                                                              |
       ^
                    |   EVP_PKEY_derive_init                     |              EVP_PKEY_verify_init
       |
                    +---------------------------------------+                                      |
       +---------------------------------------+
                                                            |    |    |
        +-------------+                                              |              |              |
       +-------------+
        |                     |----------------------------+               |           |           |
       +----------------------------|             |
        |   digest   sign   |     EVP_PKEY_sign              |          |      |       |           |
       EVP_PKEY_verify_recover   |   verify    |
        |                     |<---------------------------+               |           |           |
       +--------------------------->|   recover   |
        +-------------+                                              |              |              |
       +-------------+
                    ^                                                 |              |             |
       ^
                    |            EVP_PKEY_sign_init                       |           |            |
       EVP_PKEY_verify_recover_init   |
                    +---------------------------------+               |              |             |
       +---------------------------------+
                                                      |     |    |    |     |
        +-------------+                                   |         |         |         |          |
       +-------------+
        |                 |----------------------------+      |         |        |        |        |
       +----------------------------|             |
        | decapsulate |   EVP_PKEY_decapsulate     |  |     |    |    |     |   |   EVP_PKEY_decrypt
       |   decrypt   |
        |                 |<---------------------------+      |         |        v        |        |
       +--------------------------->|             |
        +-------------+                                      |           +-------------+           |
       +-------------+
                    ^                                             +---|                        |---+
       ^
                    |     EVP_PKEY_decapsulate_init       |             |      EVP_PKEY_decrypt_init
       |
                    +-------------------------------------|                                    newed
       |-------------------------------------+
                                                          |             |
                                                      +---|             |---+
        +-------------+                                       |           +-------------+          |
       +-------------+
        |                 |----------------------------+      |          |              |          |
       +----------------------------|             |
        |  encapsulate  |   EVP_PKEY_encapsulate     |  |     |         |     |  |  EVP_PKEY_encrypt
       |   encrypt   |
        |                 |<---------------------------+      |          |              |          |
       +--------------------------->|             |
        +-------------+                                     |           |               |          |
       +-------------+
                    ^                                      |           |               |           |
       ^
                    |     EVP_PKEY_encapsulate_init   |     |         |     |  EVP_PKEY_encrypt_init
       |
                    +---------------------------------+                    |                       |
       +---------------------------------+
                                                            |         |
                    +---------------------------------------+
       +---------------------------------------+
                    |     EVP_PKEY_paramgen_init                                EVP_PKEY_keygen_init
       |
                    v
       v
        +-------------+
       +-------------+
        |                                                             |----------------------------+
       +----------------------------|             |
        |       parameter       |                                 |                                |
       |     key     |
        |                          generation                         |<---------------------------+
       +--------------------------->|  generation |
        +-------------+    EVP_PKEY_paramgen                                         EVP_PKEY_keygen
       +-------------+
                          EVP_PKEY_gen                                            EVP_PKEY_gen


                                           + - - - - - +                    +-----------+
                                           '           ' EVP_PKEY_CTX_free  |           |
                                           ' any state '------------------->|   freed   |
                                           '           '                    |           |
                                           + - - - - - +                    +-----------+

   Formal State Transitions
       This section defines all of the legal state transitions.  This is the canonical list.
        Function                                                                                Call
       ----------------------------------------------------------------------     Current      State
       ----------------------------------------------------------------------
                                      start       newed         digest         verify         verify
       encrypt       decrypt       derive        encapsulate    decapsulate    parameter         key
       freed
                                                            sign                             recover
       generation   generation
        EVP_PKEY_CTX_new              newed
        EVP_PKEY_CTX_new_id           newed
        EVP_PKEY_CTX_new_from_name    newed
        EVP_PKEY_CTX_new_from_pkey    newed
        EVP_PKEY_sign_init                      digest         digest         digest          digest
       digest       digest       digest       digest       digest       digest       digest
                                               sign             sign            sign            sign
       sign         sign         sign         sign         sign         sign         sign
        EVP_PKEY_sign                                      digest
                                                            sign
        EVP_PKEY_verify_init                    verify         verify         verify          verify
       verify       verify       verify       verify       verify       verify       verify
        EVP_PKEY_verify                                                 verify
        EVP_PKEY_verify_recover_init             verify         verify         verify         verify
       verify       verify       verify       verify       verify       verify       verify
                                              recover        recover         recover         recover
       recover      recover      recover      recover      recover      recover      recover
        EVP_PKEY_verify_recover                                                      verify
                                                                                     recover
        EVP_PKEY_encrypt_init                   encrypt        encrypt        encrypt        encrypt
       encrypt      encrypt      encrypt      encrypt      encrypt      encrypt      encrypt
        EVP_PKEY_encrypt
       encrypt
        EVP_PKEY_decrypt_init                   decrypt        decrypt        decrypt        decrypt
       decrypt      decrypt      decrypt      decrypt      decrypt      decrypt      decrypt
        EVP_PKEY_decrypt
       decrypt
        EVP_PKEY_derive_init                     derive         derive         derive         derive
       derive       derive       derive       derive       derive       derive       derive
        EVP_PKEY_derive_set_peer
       derive
        EVP_PKEY_derive
       derive
        EVP_PKEY_encapsulate_init             encapsulate   encapsulate   encapsulate    encapsulate
       encapsulate  encapsulate  encapsulate  encapsulate  encapsulate  encapsulate  encapsulate
        EVP_PKEY_encapsulate
       encapsulate
        EVP_PKEY_decapsulate_init              decapsulate   decapsulate   decapsulate   decapsulate
       decapsulate  decapsulate  decapsulate  decapsulate  decapsulate  decapsulate  decapsulate
        EVP_PKEY_decapsulate
       decapsulate
        EVP_PKEY_paramgen_init                parameter      parameter      parameter      parameter
       parameter    parameter    parameter    parameter    parameter    parameter    parameter
                                             generation     generation     generation     generation
       generation   generation   generation   generation   generation   generation   generation
        EVP_PKEY_paramgen
       parameter
                                                                                                                                                                  generation
        EVP_PKEY_keygen_init                      key            key             key             key
       key          key          key          key          key          key          key
                                             generation     generation     generation     generation
       generation   generation   generation   generation   generation   generation   generation
        EVP_PKEY_keygen
       key
                                                                                                                                                                               generation
        EVP_PKEY_gen
       parameter       key
                                                                                                                                                                  generation
       generation
        EVP_PKEY_CTX_get_params                  newed         digest         verify          verify
       encrypt      decrypt      derive      encapsulate  decapsulate  parameter       key
                                                            sign                             recover
       generation   generation
        EVP_PKEY_CTX_set_params                  newed         digest         verify          verify
       encrypt      decrypt      derive      encapsulate  decapsulate  parameter       key
                                                            sign                             recover
       generation   generation
        EVP_PKEY_CTX_gettable_params             newed         digest         verify          verify
       encrypt      decrypt      derive      encapsulate  decapsulate  parameter       key
                                                            sign                             recover
       generation   generation
        EVP_PKEY_CTX_settable_params             newed         digest         verify          verify
       encrypt      decrypt      derive      encapsulate  decapsulate  parameter       key
                                                            sign                             recover
       generation   generation
        EVP_PKEY_CTX_free              freed      freed          freed          freed          freed
       freed        freed        freed        freed        freed        freed        freed

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

SEE ALSO
       EVP_PKEY_new(3),   EVP_PKEY_decapsulate(3),   EVP_PKEY_decrypt(3),   EVP_PKEY_encapsulate(3),
       EVP_PKEY_encrypt(3),      EVP_PKEY_derive(3),      EVP_PKEY_keygen(3),      EVP_PKEY_sign(3),
       EVP_PKEY_verify(3), EVP_PKEY_verify_recover(3)

HISTORY
       The provider PKEY interface was introduced in OpenSSL 3.0.

COPYRIGHT
       Copyright 2021-2023 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>.

3.0.13                                       2026-07-29                        LIFE_CYCLE-PKEY(7SSL)
life_cycle-pkey(7ssl) □✕
NAME DESCRIPTION
State Transition Diagram Formal State Transitions
NOTES SEE ALSO HISTORY COPYRIGHT

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