EVP_KEYEXCH_free.pod 4.4 KB

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  1. =pod
  2. =head1 NAME
  3. EVP_KEYEXCH_fetch, EVP_KEYEXCH_free, EVP_KEYEXCH_up_ref,
  4. EVP_KEYEXCH_get0_provider, EVP_KEYEXCH_is_a, EVP_KEYEXCH_do_all_provided,
  5. EVP_KEYEXCH_names_do_all, EVP_KEYEXCH_get0_name, EVP_KEYEXCH_get0_description,
  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(OSSL_LIB_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_get0_provider(const EVP_KEYEXCH *exchange);
  15. int EVP_KEYEXCH_is_a(const EVP_KEYEXCH *exchange, const char *name);
  16. const char *EVP_KEYEXCH_get0_name(const EVP_KEYEXCH *exchange);
  17. void EVP_KEYEXCH_do_all_provided(OSSL_LIB_CTX *libctx,
  18. void (*fn)(EVP_KEYEXCH *exchange, void *arg),
  19. void *arg);
  20. int EVP_KEYEXCH_names_do_all(const EVP_KEYEXCH *exchange,
  21. void (*fn)(const char *name, void *data),
  22. void *data);
  23. const char *EVP_KEYEXCH_get0_description(const EVP_KEYEXCH *keyexch);
  24. const OSSL_PARAM *EVP_KEYEXCH_gettable_ctx_params(const EVP_KEYEXCH *keyexch);
  25. const OSSL_PARAM *EVP_KEYEXCH_settable_ctx_params(const EVP_KEYEXCH *keyexch);
  26. =head1 DESCRIPTION
  27. EVP_KEYEXCH_fetch() fetches the key exchange implementation for the given
  28. I<algorithm> from any provider offering it, within the criteria given
  29. by the I<properties>.
  30. See L<crypto(7)/ALGORITHM FETCHING> for further information.
  31. The returned value must eventually be freed with EVP_KEYEXCH_free().
  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. EVP_KEYEXCH_up_ref() increments the reference count for an B<EVP_KEYEXCH>
  37. structure.
  38. EVP_KEYEXCH_get0_provider() returns the provider that I<exchange> was
  39. fetched from.
  40. EVP_KEYEXCH_is_a() checks if I<exchange> is an implementation of an
  41. algorithm that's identifiable with I<name>.
  42. EVP_KEYEXCH_get0_name() returns the algorithm name from the provided
  43. implementation for the given I<exchange>. Note that the I<exchange> may have
  44. multiple synonyms associated with it. In this case the first name from the
  45. algorithm definition is returned. Ownership of the returned string is retained
  46. by the I<exchange> object and should not be freed by the caller.
  47. EVP_KEYEXCH_names_do_all() traverses all names for the I<exchange>, and
  48. calls I<fn> with each name and I<data>.
  49. EVP_KEYEXCH_get0_description() returns a description of the I<keyexch>, meant
  50. for display and human consumption. The description is at the discretion of
  51. the I<keyexch> implementation.
  52. EVP_KEYEXCH_do_all_provided() traverses all key exchange implementations by
  53. all activated providers in the library context I<libctx>, and for each
  54. of the implementations, calls I<fn> with the implementation method and
  55. I<data> as arguments.
  56. EVP_KEYEXCH_gettable_ctx_params() and EVP_KEYEXCH_settable_ctx_params() return
  57. a constant L<OSSL_PARAM(3)> array that describes the names and types of key
  58. parameters that can be retrieved or set by a key exchange algorithm using
  59. L<EVP_PKEY_CTX_get_params(3)> and L<EVP_PKEY_CTX_set_params(3)>.
  60. =head1 RETURN VALUES
  61. EVP_KEYEXCH_fetch() returns a pointer to a B<EVP_KEYEXCH> for success
  62. or NULL for failure.
  63. EVP_KEYEXCH_up_ref() returns 1 for success or 0 otherwise.
  64. EVP_KEYEXCH_names_do_all() returns 1 if the callback was called for all
  65. names. A return value of 0 means that the callback was not called for any names.
  66. EVP_KEYEXCH_is_a() returns 1 of I<exchange> was identifiable,
  67. otherwise 0.
  68. EVP_KEYEXCH_gettable_ctx_params() and EVP_KEYEXCH_settable_ctx_params() return
  69. a constant L<OSSL_PARAM(3)> array or NULL on error.
  70. =head1 SEE ALSO
  71. L<crypto(7)/ALGORITHM FETCHING>, L<OSSL_PROVIDER(3)>
  72. =head1 HISTORY
  73. The functions described here were added in OpenSSL 3.0.
  74. =head1 COPYRIGHT
  75. Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
  76. Licensed under the Apache License 2.0 (the "License"). You may not use
  77. this file except in compliance with the License. You can obtain a copy
  78. in the file LICENSE in the source distribution or at
  79. L<https://www.openssl.org/source/license.html>.
  80. =cut