life_cycle-kdf - The KDF algorithm life-cycle
All key derivation functions (KDFs) and pseudo random functions (PRFs) go through a number of stages in their life-cycle:
This state represents the KDF/PRF before it has been allocated. It is the starting state for any life-cycle transitions.
This state represents the KDF/PRF after it has been allocated.
This state represents the KDF/PRF when it is set up and capable of generating output.
This state is entered when the KDF/PRF is freed. It is the terminal state for all life-cycle transitions.
The usual life-cycle of a KDF/PRF is illustrated: +-------------------+ | start | +-------------------+ | | EVP_KDF_CTX_new v +-------------------+ | newed | <+ +-------------------+ | | | | EVP_KDF_derive | v | EVP_KDF_CTX_reset EVP_KDF_derive +-------------------+ | + - - - - - - - - | | | ' | deriving | | + - - - - - - - -> | | -+ +-------------------+ | | EVP_KDF_CTX_free v +-------------------+ | freed | +-------------------+
This section defines all of the legal state transitions. This is the canonical list. Function Call ------------- Current State ------------- start newed deriving freed EVP_KDF_CTX_new newed EVP_KDF_derive deriving deriving EVP_KDF_CTX_free freed freed freed EVP_KDF_CTX_reset newed newed EVP_KDF_CTX_get_params newed deriving EVP_KDF_CTX_set_params newed deriving EVP_KDF_CTX_gettable_params newed deriving EVP_KDF_CTX_settable_params newed deriving
At some point the EVP layer will begin enforcing the transitions described herein.
provider-kdf (7), EVP_KDF (3).
The provider KDF interface was introduced in OpenSSL 3.0.
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