doc/man3/EVP_KEYEXCH_free.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 EVP_KEYEXCH_fetch, EVP_KEYEXCH_free, EVP_KEYEXCH_up_ref, EVP_KEYEXCH_provider,
   6 EVP_KEYEXCH_is_a, EVP_KEYEXCH_do_all_provided,
   7 EVP_KEYEXCH_number, EVP_KEYEXCH_names_do_all,
   8 EVP_KEYEXCH_gettable_ctx_params, EVP_KEYEXCH_settable_ctx_params
   9 - Functions to manage EVP_KEYEXCH algorithm objects
  10
  11 =head1 SYNOPSIS
  12
  13  #include <openssl/evp.h>
  14
  15  EVP_KEYEXCH *EVP_KEYEXCH_fetch(OSSL_LIB_CTX *ctx, const char *algorithm,
  16                                 const char *properties);
  17  void EVP_KEYEXCH_free(EVP_KEYEXCH *exchange);
  18  int EVP_KEYEXCH_up_ref(EVP_KEYEXCH *exchange);
  19  OSSL_PROVIDER *EVP_KEYEXCH_provider(const EVP_KEYEXCH *exchange);
  20  int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *exchange, const char *name);
  21  int EVP_KEYEXCH_number(const EVP_KEYEXCH *exchange);
  22  void EVP_KEYEXCH_do_all_provided(OSSL_LIB_CTX *libctx,
  23                                   void (*fn)(EVP_KEYEXCH *exchange, void *arg),
  24                                   void *arg);
  25  void EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *exchange,
  26                                void (*fn)(const char *name, void *data),
  27                                void *data);
  28  const OSSL_PARAM *EVP_KEYEXCH_gettable_ctx_params(const EVP_KEYEXCH *keyexch);
  29  const OSSL_PARAM *EVP_KEYEXCH_settable_ctx_params(const EVP_KEYEXCH *keyexch);
  30
  31 =head1 DESCRIPTION
  32
  33 EVP_KEYEXCH_fetch() fetches the key exchange implementation for the given
  34 I<algorithm> from any provider offering it, within the criteria given
  35 by the I<properties>.
  36 See L<provider(7)/Fetching algorithms> for further information.
  37
  38 The returned value must eventually be freed with EVP_KEYEXCH_free().
  39
  40 EVP_KEYEXCH_free() decrements the reference count for the B<EVP_KEYEXCH>
  41 structure. Typically this structure will have been obtained from an earlier call
  42 to EVP_KEYEXCH_fetch(). If the reference count drops to 0 then the
  43 structure is freed.
  44
  45 EVP_KEYEXCH_up_ref() increments the reference count for an B<EVP_KEYEXCH>
  46 structure.
  47
  48 EVP_KEYEXCH_provider() returns the provider that I<exchange> was fetched from.
  49
  50 EVP_KEYEXCH_is_a() checks if I<exchange> is an implementation of an
  51 algorithm that's identifiable with I<name>.
  52
  53 EVP_KEYEXCH_number() returns the internal dynamic number assigned to
  54 the I<exchange>.
  55
  56 EVP_KEYEXCH_names_do_all() traverses all names for the I<exchange>, and
  57 calls I<fn> with each name and I<data>.
  58
  59 EVP_KEYEXCH_do_all_provided() traverses all key exchange implementations by
  60 all activated providers in the library context I<libctx>, and for each
  61 of the implementations, calls I<fn> with the implementation method and
  62 I<data> as arguments.
  63
  64 EVP_KEYEXCH_gettable_ctx_params() and EVP_KEYEXCH_settable_ctx_params() return
  65 a constant B<OSSL_PARAM> array that describes the names and types of key
  66 parameters that can be retrieved or set by a key exchange algorithm using
  67 L<EVP_PKEY_CTX_get_params(3)> and L<EVP_PKEY_CTX_set_params(3)>.
  68
  69 =head1 RETURN VALUES
  70
  71 EVP_KEYEXCH_fetch() returns a pointer to a B<EVP_KEYEXCH> for success
  72 or NULL for failure.
  73
  74 EVP_KEYEXCH_up_ref() returns 1 for success or 0 otherwise.
  75
  76 EVP_KEYEXCH_is_a() returns 1 of I<exchange> was identifiable,
  77 otherwise 0.
  78
  79 EVP_KEYEXCH_number() returns an integer.
  80
  81 EVP_KEYEXCH_gettable_ctx_params() and EVP_KEYEXCH_settable_ctx_params() return
  82 a constant B<OSSL_PARAM> array or NULL on error.
  83
  84 =head1 SEE ALSO
  85
  86 L<provider(7)/Fetching algorithms>, L<OSSL_PROVIDER(3)>
  87
  88 =head1 HISTORY
  89
  90 The functions described here were added in OpenSSL 3.0.
  91
  92 =head1 COPYRIGHT
  93
  94 Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.
  95
  96 Licensed under the Apache License 2.0 (the "License").  You may not use
  97 this file except in compliance with the License.  You can obtain a copy
  98 in the file LICENSE in the source distribution or at
  99 L<https://www.openssl.org/source/license.html>.
 100
 101 =cut