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