EVP_KEYEXCH_free.pod 3.7 KB

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