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