life_cycle-rand - The RAND algorithm life-cycle
All random number generator (RANDs) go through a number of stages in their
  life-cycle:
  - start
- This state represents the RAND before it has been allocated. It is the
      starting state for any life-cycle transitions.
- newed
- This state represents the RAND after it has been allocated but unable to
      generate any output.
- instantiated
- This state represents the RAND when it is set up and capable of generating
      output.
- uninstantiated
- This state represents the RAND when it has been shutdown and it is no
      longer capable of generating output.
- freed
- This state is entered when the RAND is freed. It is the terminal state for
      all life-cycle transitions.
The usual life-cycle of a RAND is illustrated:
 +-------------------------+
 | start |
 +-------------------------+
 |
 | EVP_RAND_CTX_new
 v
 +-------------------------+
 | newed |
 +-------------------------+
 |
 | EVP_RAND_instantiate
 v
 EVP_RAND_generate +-------------------------+
 +-------------------- | |
 | | instantiated |
 +-------------------> | | <+
 +-------------------------+ '
 | '
 | EVP_RAND_uninstantiate ' EVP_RAND_instantiate
 v '
 +-------------------------+ '
 | uninstantiated | -+
 +-------------------------+
 |
 | EVP_RAND_CTX_free
 v
 +-------------------------+
 | freed |
 +-------------------------+
This section defines all of the legal state transitions. This is the canonical
  list.
 Function Call ------------------ Current State ------------------
 start newed instantiated uninstantiated freed
 EVP_RAND_CTX_new newed
 EVP_RAND_instantiate instantiated
 EVP_RAND_generate instantiated
 EVP_RAND_uninstantiate uninstantiated
 EVP_RAND_CTX_free freed freed freed freed
 EVP_RAND_CTX_get_params newed instantiated uninstantiated freed
 EVP_RAND_CTX_set_params newed instantiated uninstantiated freed
 EVP_RAND_CTX_gettable_params newed instantiated uninstantiated freed
 EVP_RAND_CTX_settable_params newed instantiated uninstantiated freed
At some point the EVP layer will begin enforcing the transitions described
  herein.
provider-rand(7), EVP_RAND(3).
The provider RAND interface was introduced in OpenSSL 3.0.
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