doc/man3/EVP_KEM_free.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 EVP_KEM_fetch, EVP_KEM_free, EVP_KEM_up_ref,
   6 EVP_KEM_number, EVP_KEM_is_a, EVP_KEM_provider,
   7 EVP_KEM_do_all_provided, EVP_KEM_names_do_all,
   8 EVP_KEM_gettable_ctx_params, EVP_KEM_settable_ctx_params
   9 - Functions to manage EVP_KEM algorithm objects
  10
  11 =head1 SYNOPSIS
  12
  13  #include <openssl/evp.h>
  14
  15  EVP_KEM *EVP_KEM_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
  16                         const char *properties);
  17  void EVP_KEM_free(EVP_KEM *kem);
  18  int EVP_KEM_up_ref(EVP_KEM *kem);
  19  int EVP_KEM_number(const EVP_KEM *kem);
  20  int EVP_KEM_is_a(const EVP_KEM *kem, const char *name);
  21  OSSL_PROVIDER *EVP_KEM_provider(const EVP_KEM *kem);
  22  void EVP_KEM_do_all_provided(OSSL_LIB_CTX *libctx,
  23                               void (*fn)(EVP_KEM *kem, void *arg), void *arg);
  24  int EVP_KEM_names_do_all(const EVP_KEM *kem,
  25                           void (*fn)(const char *name, void *data), void *data);
  26  const OSSL_PARAM *EVP_KEM_gettable_ctx_params(const EVP_KEM *kem);
  27  const OSSL_PARAM *EVP_KEM_settable_ctx_params(const EVP_KEM *kem);
  28
  29 =head1 DESCRIPTION
  30
  31 EVP_KEM_fetch() fetches the implementation for the given B<algorithm> from any
  32 provider offering it, within the criteria given by the B<properties> and in the
  33 scope of the given library context B<ctx> (see L<OSSL_LIB_CTX(3)>). The algorithm
  34 will be one offering functions for performing asymmetric kem related tasks such
  35 as key encapsulation and decapsulation.
  36 See L<provider(7)/Fetching algorithms> for further information.
  37
  38 The returned value must eventually be freed with EVP_KEM_free().
  39
  40 EVP_KEM_free() decrements the reference count for the B<EVP_KEM> structure.
  41 Typically this structure will have been obtained from an earlier call to
  42 EVP_KEM_fetch(). If the reference count drops to 0 then the structure is freed.
  43
  44 EVP_KEM_up_ref() increments the reference count for an B<EVP_KEM> structure.
  45
  46 EVP_KEM_is_a() returns 1 if I<kem> is an implementation of an
  47 algorithm that's identifiable with I<name>, otherwise 0.
  48
  49 EVP_KEM_provider() returns the provider that I<kem> was fetched from.
  50
  51 EVP_KEM_do_all_provided() traverses all EVP_KEMs implemented by all activated
  52 providers in the given library context I<libctx>, and for each of the
  53 implementations, calls the given function I<fn> with the implementation method
  54 and the given I<arg> as argument.
  55
  56 EVP_KEM_number() returns the internal dynamic number assigned to I<kem>.
  57
  58 EVP_KEM_names_do_all() traverses all names for I<kem>, and calls I<fn> with
  59 each name and I<data>.
  60
  61 EVP_KEM_gettable_ctx_params() and EVP_KEM_settable_ctx_params() return
  62 a constant B<OSSL_PARAM> array that describes the names and types of key
  63 parameters that can be retrieved or set by a key encapsulation algorithm using
  64 L<EVP_PKEY_CTX_get_params(3)> and L<EVP_PKEY_CTX_set_params(3)>.
  65
  66 =head1 RETURN VALUES
  67
  68 EVP_KEM_fetch() returns a pointer to an B<EVP_KEM> for success or B<NULL> for
  69 failure.
  70
  71 EVP_KEM_up_ref() returns 1 for success or 0 otherwise.
  72
  73 EVP_KEM_names_do_all() returns 1 if the callback was called for all names. A
  74 return value of 0 means that the callback was not called for any names.
  75
  76 EVP_KEM_gettable_ctx_params() and EVP_KEM_settable_ctx_params() return
  77 a constant B<OSSL_PARAM> array or NULL on error.
  78
  79 =head1 SEE ALSO
  80
  81 L<provider(7)/Fetching algorithms>, L<OSSL_PROVIDER(3)>
  82
  83 =head1 HISTORY
  84
  85 The functions described here were added in OpenSSL 3.0.
  86
  87 =head1 COPYRIGHT
  88
  89 Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
  90
  91 Licensed under the Apache License 2.0 (the "License").  You may not use
  92 this file except in compliance with the License.  You can obtain a copy
  93 in the file LICENSE in the source distribution or at
  94 L<https://www.openssl.org/source/license.html>.
  95
  96 =cut